How tectonics, sediment, and water created one of the most productive landscapes on Earth.
Aerial view of Californiaโs Central Valley, where Interstate 5 slices through a vast patchwork of irrigated fields, some of the most productive farmland on Earth, shaped by deep alluvial soils and Sierra Nevada snowmelt. (Photo: Erik Olsen)
I love Californiaโs bizarre, complicated geology. For many years, I had a wonderful raised-relief map of the state on my wall made by Hubbard Scientific (it hangs on my sonโs bedroom wall today). On the map, color and molded plastic contours reveal the stateโs diverse and often startling geological formations. I loved staring at it, touching it, imagining how those landscapes came to be over geologic time.
There is so much going on here geologically compared to almost any other state that geologists often describe California as one of the best natural laboratories on Earth, a place so rich and varied that entire careers have been built trying to understand how all its pieces fit together. As the U.S. Geological Survey (USGS) puts it, nearly every major force that shapes the Earthโs crust is visible here, from plate collision and volcanism to basin formation and mountain uplift. Some of my favorite writers, like John McPhee, have described California as a collage of geological fragments, assembled piece by piece over deep time, in a way that more closely resembles an entire continent than a single region.
But when we think about Californiaโs geology, most of us probably imagine the Sierra Nevadaโs towering granite peaks, the pent-up force of the San Andreas Fault, or the fact that Lassen Peak is still an active volcano. Those places grab our attention. Yet when it comes to a geological feature that has quietly shaped daily life in California more than almost any other, we should consider the Central Valley, arguably the stateโs most important geological masterpiece.
Topographical and irrigation map of the Great Central Valley of California: embracing the Sacramento, San Joaquin, Tulare and Kern Valleys and the bordering foothills (Source: NYPL Digital Collection)
Sure, the valley is flat as a tabletop, stretching out for mile after mile as you drive Interstate 5 or Highway 99 (one of my favorites), but once you consider how it formed and what lies beneath the surface, the Central Valley reveals itself as a truly remarkable place on the planet, another superlative in our state, which, of course, is already full of them.
The Central Valley was formed when tectonic forces lowered a broad swath of Californiaโs crust between the rising Sierra Nevada to the east and the Coast Ranges to the west, creating a long, subsiding basin that slowly filled with sediment eroded from those mountains over millions of years. For thousands of years, the southern end of the valley was dominated by Lake Tulare, a mega-freshwater lake that was once the largest freshwater lake west of the Mississippi. You might remember that just a few years ago, Lake Tulare briefly reappeared after a series of powerful atmospheric river storms. I went up there and flew my drone because I was working on a story about the construction of Californiaโs long-troubled high-speed rail, which had halted construction because of the new old lake.
Lake Tulare reemerges in the southern San Joaquin Valley after powerful winter storms, flooding roads and farmland and briefly restoring the historic inland lake that once dominated this basin. (Photo: Erik Olsen)
On the other side in the west, the Coast Ranges rise up, hemming in the valley and basically holding it in place, forming something like a gigantic, hundreds-of-miles-long bathtub. One popular Instagrammer commented that it looks as if someone used a huge ice cream scoop to dig out the valley. As the surrounding mountains continued to rise, rain, snowmelt, and wind carried untold tons of silt and sediment downslope, steadily depositing them into this enormous basin over millions of years.
This process created what geologists call the Great Valley Sequence, a staggering accumulation of sedimentary material that, in some western portions of the basin, reaches a depth of 20,000 meters, or approximately 66,000 feet. Ten MILES.
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This long, slow process produced what geologists call the Great Valley Sequence, an immense stack of sedimentary rock built up over tens of millions of years as the basin steadily subsided and filled. In some western portions of the valley, that accumulated package reaches a depth of 20,000 meters in thickness, about 66,000 feet, or close to ten miles of layered geological history lying beneath the surface. Thatโs kind of mind-blowing.
Endless rows of pistachio orchards stretch across the Central Valley at dusk, a geometric testament to the deep soils and engineered water systems that have turned this ancient basin into one of the worldโs great agricultural landscapes. (Photo: Erik Olsen)
Itโs not just โdirtโ; itโs a ridiculously deep, nutrient-rich record of Californiaโs geologic history. There are the remains of trillions of diatoms, or microscopic plankton, whose organic remains were crushed into oil shales that are home to significant petroleum deposits. During the late Pleistocene and into the Holocene, the southern end of the valley was dominated by Lake Tulare, mentioned above, a vast freshwater lake that in wet periods spread across 600 to 800 square miles, making it the largest freshwater lake west of the Mississippi. As the water evaporated and drained, the valley floor became exceptionally flat, similar to what we see today.
Most valleys are narrow corridors carved by a single river, but the Central Valley is a vast, enclosed catchment shaped by many rivers, trapping minerals and sediments from surrounding mountains rather than letting them wash quickly out to sea. This mix created near-ideal conditions for agriculture. For the uninitiated, the Central Valley is typically divided into two major sections: the northern third, known as the Sacramento Valley, and the southern two-thirds, known as the San Joaquin Valley. That lower region can be further broken down into the San Joaquin Basin to the north and the Tulare Basin to the south.
Relief map of California showing the Central Valley standing out as a wide, uninterrupted green swath between the rugged Sierra Nevada and the Coast Ranges, its flat, low-lying basin sharply contrasting with the surrounding mountains that frame and define it.
Today, because of all that fertility, the Central Valley is one of the worldโs most productive agricultural regions, growing over 230 different crops. It produces roughly a quarter of the nationโs food by value, supplies about 40 percent of U.S. fruits, nuts, and vegetables, and dominates global markets for crops like almonds, pistachios, strawberries, tomatoes, and table grapes. Truly a global breadbasket.
Of course, none of this would have been possible without water. The real turning point in Californiaโs story was learning how to capture it, move it, and store it. From mountain snowpack to canals and reservoirs, controlling water has been the quiet engine behind much of the stateโs success. When human engineering intervened in the 20th century through the Central Valley Project and the State Water Project, it essentially redirected a geological process that was already in place, replacing seasonal floods and ancient lakes with a controlled system of dams and canals.
Roadside cutout farmer holding bright green heads of lettuce at the edge of a Central Valley field, a playful nod to the regionโs identity as one of the most productive agricultural landscapes in the world. (Photo: Erik Olsen)
Alas, this productivity is not without geological limits, and weโve done a pretty good job over-exploiting the valleyโs resources, particularly groundwater, to achieve these things. The same porous sediments that store our life-giving groundwater are susceptible to compaction. In parts of the San Joaquin Valley, excessive pumping has caused the land to subside, sinking by as much as 28 feet in some locations, causing the soil to crack and the landscape to physically lower as the water is withdrawn. How we deal with that is a whole other story. Recent storms have helped Californiaโs water supply tremendously, but the state seems destined to remain in a permanently precarious state of drought.
But when you talk geology, you talk deep time. You talk about eons and erosion, mountain ranges that rise and are slowly worn down, sometimes leaving behind something as breathtaking as the granite domes of Yosemite.Against that scale, the Central Valley can seem almost plain, but as I hope Iโve made the case here, when you look a little closer at even the most mundane things, you realize there is magnificence there, and few places on this planet are as magnificent as the state of California.
We all know California is known for earthquakes. AND most people probably know there’s a reason for that: California lies along the Pacific Ring of Fire, and it also sits at the boundary between the Pacific and North American tectonic plates, creating the San Andreas Fault and making it especially prone to seismic shaking. Even if you’ve lived here for just a short while, the chances are you’ve felt a tremble or two.
Of course, the biggest earthquake most people are aware of in California was the 1906 earthquake in San Francisco, which shook the city hard and led to a massive, all-consuming fire that together destroyed more than 28,000 buildings, killed an estimated 3,000 people, left roughly a quarter million residents homeless, and reshaped the cityโs development and building practices for decades afterward. (Here’s a story about one particularly important building). One of my favorite books on the subject is Simon Winchesterโs Crack at the Edge of the World, which is filled with wonderful facts and stories about Californiaโs precarious geology and what happened that day in San Francisco.
More recent events continue to underscore the ever-present threat of significant temblors. In December 2024, a 7.0-magnitude earthquake struck off the coast near Eureka, prompting tsunami warnings and evacuations. More recently, in March 2025, the Bay Area experienced a series of minor tremors along the Hayward Fault. While these quakes caused minimal damage, there is always the looming threat of ‘The Big One’, a potentially catastrophic earthquake expected along the San Andreas Fault, well, any day now . Scientists warn that the southern section, overdue for a major rupture, could trigger widespread destruction, with estimates suggesting a magnitude 7.8 event could result in “significant casualties and economic losses”.
Damage to Interstate 880 in Oakland, CA, after it collapsed during the Loma Prieta earthquake In October 1989. (Photo: Paul Sakuma/AP)
But what about that number, 7.8? Where does it actually come from, and what does it mean?
When we talk about measuring earthquakes: their size, their energy, their destructive potential, most of us still instinctively think of the Richter scale. Itโs now shorthand for seismic strength, although, ironically, scientists today rely on other, more modern magnitude systems. We’ll get to that shortly. But the Richter scale remains one of the most influential ideas in the history of earthquake science.
The story of how it came to exist starts in a lab at a world-renowned scientific institution in Pasadena: the California Institute of Technology (CalTech). It begins with a physicist named Charles Richter.
In 1935, working with German-born seismologist Beno Gutenberg, Richter laid the groundwork for modern earthquake study and quantification. Their breakthrough work helped transform vague and subjective observations into precise, quantifiable data. Scientists could now better assess seismic risk and ultimately help protect lives and infrastructure. So the effort not only changed how we understand earthquakes, it laid the foundation for future advances in seismic prediction and preparedness.
Charles Richter studies a seismograph log that records the earth’s movements. (Credit: Wikipedia and Gil Cooper, Los Angeles Times)
At the time, existing intensity-based earthquake measurements relied on subjective observations and the so-called the Mercalli Intensity Scale. That means that an earthquakeโs severity was determined by visible damage and how people felt them. So, for example, a small earthquake near a city might appear โstrongerโ than a larger earthquake in a remote area simply because it was felt by more people and caused more visible damage. For example, the 1857 Fort Tejon earthquake, estimated around magnitude 7.9, ruptured hundreds of miles of the San Andreas Fault, but because it struck a sparsely populated stretch of desert and ranch land, it caused relatively little recorded damage and few deaths.
Like any good scientist, Richter wanted to create a precise, instrumental method to measure earthquake magnitude. He and Gutenberg designed the Richter scale by studying seismic wave amplitudes recorded on Wood-Anderson torsion seismometers, an instrument developed in the 1920s to detect horizontal ground movement. Using a base-10 logarithmic function, they developed a system where each whole number increase represented a tenfold increase in amplitude and roughly 31 times more energy release. This allowed them to compress a wide range of earthquake sizes into a manageable, readable scale. So, for example, a magnitude 6 quake shakes the ground 10ร more than a magnitude 5. Also, a magnitude 7 quake releases about 1,000ร more energy than a magnitude 5 (i.e. 31.6 ร 31.6 โ 1,000).
How the Richter Magnitude Scale of Earthquakes is determined from a seismograph. (Credit: Benjamin J. Burger)
The innovation allowed scientists to compare earthquakes across different locations and time periods, significantly improving seismic measurement and research.
Once the Richter scale came into being, it not only changed how scientists described earthquakes, it changed how we all thought about them. Earthquakes were no longer defined only by damage or casualties, but by a single, authoritative number. And so by the 1960s and 1970s, โthe Richter scaleโ had become standard language in news reports and scientific writing. Even today, long after researchers have moved to newer magnitude systems, you still occasionally see it in news reports.
The Richter Scale, and Richter himself, became so well known on campus, that one of Caltechโs great comic writers and performers, J. Kent Clark, actually wrote a song about them:
โWhen the first shock hit the seismo, everything worked fine. It measured:
One, two, on the Richter scale, a shabby little shiver.
One, two, on the Richter scale, a queasy little quiver.
Waves brushed the seismograph as if a fly had flicked her.
One, two, on the Richter scale, it hardly woke up Richter.โ
Alas, Richter, according to Clark, was so โmorbidly shyโ that he never showed up to any of the performances. At first, he didnโt like the song, reportedly calling it an “insult to science”, but later in life he came to appreciate its good humor. There’s a YouTube reading of the song here.
Unfortunately for Richter, over time it became clear that the Richter scale had a fundamental flaw: it couldn’t measure the largest earthquakes accurately. Because it relies on seismic wave amplitude, very powerful quakes tend to โsaturateโ on the scale, making different events appear similar in size.
Since the 70s scientists have come up with another way to measure earthquakes called the Moment Magnitude Scale. Developed by Hiroo Kanamori and Thomas Hanks the Moment Magnitude Scale calculates how much energy an earthquake actually releases by examining the size of the fault that slipped, how far it moved, and the physical properties of the surrounding rock. The method works reliably for both small tremors and the planetโs largest earthquakes, which the original Richter scale struggled to do.
A striking view of the Palmdale roadcut, showcasing layers of exposed rock that tell the geological story of Southern California. Located just a short distance from the San Andreas Fault, this site provides a vivid snapshot of tectonic activity, where Earth’s shifting plates have shaped the landscape dramatically over millions of years. (Credit: Erik Olsen)
Of course, neither the Richter scale nor the Moment Magnitude Scale have done much to help us actually predict earthquakes. That remains an elusive dream. That said, ShakeAlert, the stateโs early-warning system, doesnโt predict quakes, but it can detect them as they begin and send alerts before the worst shaking arrives. Those seconds can be enough to drop to the ground, slow trains, or shut down sensitive systems. The system has also had misfires and missed alerts, so we’re not there yet.
Dr. Lucy Jones, who helped champion early earthquake warning in California, has said that ShakeAlert usually works exactly as intended. It is โtunedโ to avoid sending alerts for minor shaking, because otherwise people would be getting notifications all the time, creating a kind of Chicken Little problem where warnings start to lose their impact.
According to experts involved with the system, ShakeAlert is designed to send alerts for earthquakes in L.A. County with a magnitude of at least 5.0, or for quakes anywhere that are strong enough to produce โlightโ shaking in the Los Angeles area. But according to news reports, that sometimes leaves people feeling disappointed or confused. During the 2019 Ridgecrest quakes, for example, Los Angeles didnโt receive a public alert because the shaking there was below the warning threshold, although many people felt it. Jones has said the real challenge isnโt just the technology, but making sure alerts are communicated in a way people understand and trust.
If there is ever a โBig One,โ and scientists say itโs a matter of time, we can only hope weโll get even a small amount of early notice.
A few months ago, I took a fishing trip out to the western side of San Clemente Island. I woke at two in the morning to the rattle of the anchor chain dropping and stepped out onto the deck, expecting darkness all around us. Instead the night was alive with a strange glow. Dozens of squid boats floated offshore, their powerful lights illuminating the water with a bluish, Avatar-like brightness. The lights draw squid toward the surface before the crews scoop them up in nets.
As I knew from earlier research, and from being a long-time California resident, squid are one of Californiaโs top commercial fisheries, a multimillion-dollar industry built around what is known as market squid. They thrive in enormous numbers in the deep waters around the Channel Islands and up toward Santa Barbara, even though the average beachgoer rarely thinks about them. From the rail of the fishing boat I was I could see vast swarms just below the surface.
Squid boat off shore San Clemente Island (Photo: Erik Olsen)
When dawn broke, San Clemente Island emerged ahead of us, and I was struck by how stark and empty it looked. In both directions stretched the same raw, rugged coastline, with almost no sign of human presence (there were what appeared to be radio towers on the top of a peak, but no people).
It felt desolate and otherworldly. But the reality is more complicated.
The island is part of the Channel Islands, a chain that trends east to west rather than the usual northโsouth pattern of most California ranges. The Channel Islands are often called North Americaโs Galรกpagos because they support an extraordinary number of species found nowhere else, shaped by the deep isolation that defines island biogeography (we wrote about this earlier).
San Clemente Island (photo: U.S. Navy)
San Clemente is no exception. The island is abundant in wildlife, with its own collection of rare plants and animals. But what makes it stand apart from the other islands is the scale of the military activity just beyond the barren cliffs. The U.S. Navy conducts constant training here, including missile tests, amphibious landings, and live-fire exercises. The island is considered one of the most important training grounds for the United States military, operating around the clock even as endangered species cling to survival in the canyons and plateaus nearby.
San Clemente Island looks like a long volcanic ridge from offshore, but it has been one of the most important and least visible military landscapes in California for almost a century. It is the southernmost of the Channel Islands and has been owned entirely by the U.S. Navy since the late 1930s. Over time it became a central part of Naval Base Coronado, and today its main airfield supports helicopters, jets, drones, and special operations teams that rotate through the island throughout the year.
It all seemed really interesting. I desperately wanted to go ashore, but if Iโd tried, I almost certainly would have been arrested.
Live fire training exercises with mortars on San Clemente Island Photo: (Spc. William Franco Espinosa / U.S. Army National Guard)
The island began shaping military history just before World War II. In 1939, naval engineers brought early versions of the Higgins boat to San Clemente Island to test how they handled surf, wind, and timing with naval gunfire. These flat-bottomed landing craft became essential to Allied victories in places like Normandy and Guadalcanal. The islandโs rugged shoreline helped the US military refine the tactics behind the amphibious assaults that defined twentieth century warfare.
During the Cold War, San Clemente Island evolved into one of the Navyโs busiest live fire training sites. The waters around Pyramid Cove hosted decommissioned ships used as targets. Carrier air wings practiced bombing runs across the southern plateau. Marine units rehearsed ship-to-shore landings on isolated beaches, while submarines conducted simulated missions under restricted airspace. We did a short video you can watch here.
Few places on the West Coast allowed sea, air, and land forces to operate together with real weapons, and the islandโs remoteness made it ideal for rehearsing missions that couldn’t take place near populated coastlines. Yet all of this is happening just about 60 miles offshore from Los Angeles. (It took us about five hours to get back).
Higgins Boat (Photo: US Navy)
Civilian access has always been extremely limited, which is why the island only reaches the news when something unusual happens. One widely reported event occurred in 2023, when a private pilot illegally landed a small plane on the islandโs runway and then stole a Navy truck before being detained. He tried again in 2025. This kind of thing underscores how isolated and tightly controlled the installation is. For the most part, the only people who ever set foot on the island are service members using it as a sophisticated, real world training environment.
Oh, and scientists, too.
That’s because the islandโs natural history has been studied intensively. Decades ago, ranching introduced goats, sheep, and invasive plants that stripped vegetation from entire hillsides. Feral cats and rats preyed greedily on ground nesting birds, and live fire exercises fragmented habitat. By the 1970s and 1980s, San Clemente Island held one of the highest concentrations of endangered species in California, but everything was under threat.
San Clemente Island looks otherworldly and barren from a fishing boat (Photo: Erik Olsen)
Enter the U.S. Fish and Wildlife Service, which worked with the military to balance military readiness with the legal requirements of the Endangered Species Act. And it’s been, by many measures, a pretty major success.
No species became more symbolic of the struggle to protect the island than the San Clemente loggerhead shrike, a lovely, black masked songbird that lives nowhere else on Earth. By the late 1990s its wild population had fallen to as few as fourteen individuals. The Navy funded a comprehensive recovery effort that included captive breeding, predator removal, and habitat reconstruction, all with the expertise help of the San Diego Zoo Wildlife Alliance. By restoring vegetation and extensive breeding, scientists released shrikes which eventually began to hunt, build territories, and raise their young. The species is now considered one of the most successful island bird recoveries in North America.
The San Clemente Island fox, once threatened by habitat loss and predation, has rebounded significantly thanks to intensive conservation efforts that stabilized its population and restored its native ecosystem. (Photo: USFWS)
And that wasn’t the only success. Once goats and sheep were removed, native shrubs and herbs began returning to the island. Endemic plants such as the San Clemente Island lotus and San Clemente Island paintbrush, responded quickly once the pressure from grazing disappeared. In 2023, after decades of habitat recovery, the Fish and Wildlife Service announced that five island species were healthy enough to be removed from the endangered species list, a pretty cool milestone that suggested a major ecological turnaround for San Clemente and the Channel Islands as a whole.
San Clemente Island lotus (Photo: USFWS)
Today, San Clemente Island remains one of the most unusual places in California. It is a live fire training range where carrier groups, SEAL teams, and Marines rehearse some of the most complex operations in the Navy. It is also a refuge where rare birds and plants have recovered after hovering near extinction. Conservation biologists and military planners now coordinate schedules, field surveys, and habitat protections to keep both missions intact. There’s an excellent documentary on this recovery effort made by SoCal PBS.
California has become a national leader in restoring damaged ecosystems. And while the state has lost much of its original wildness over the centuries, it also offers some of the most compelling examples of species and habitats recovered from the brink. San Clemente Island is more ecologically stable today than at any point in the past century, and it continues to serve as one of the Navyโs most valuable training grounds.
You can scroll endlessly through TikTok and Instagram for quick bursts of Californiaโs beauty, but to truly sink into a subject, and to savor the craft of a great writer, you need a book. Iโm an avid reader, and over the past decade Iโve dedicated a large section of my bookshelf to books about California: its wild side, its nature, and its scientific wonders.
There are surely many other books that could be included in this top ten list, but these are the finest Iโve come across in the years since returning to live in the state.They capture the extraordinary diversity of Californiaโs landscapes and wildlife, found nowhere else on Earth, and many also explore issues and themes that hold deep importance for the state and its people. Although Iโve read some of these titles digitally, I love having many of them in print, because there are few things more satisfying than settling into a beach, a forest campsite, or a favorite chair at home with a beautifully made book in hand.
I first discovered Rosanna Xiaโs work through her stunning exposรฉ on the thousands of DDT barrels found dumped on the seafloor near Catalina Island. It remains one of the most shocking, and yet not technically illegal, environmental scandals in Californiaโs history.
Her recent book, California Against the Sea: Visions for Our Vanishing Coastline, is a beautifully written and deeply reported look at how Californiaโs coastal communities are confronting the realities of climate change and rising seas. Xia travels the length of the state, from Imperial Beach to Pacifica, weaving together science, policy, and personal stories to show how erosion, flooding, and climate change are already reshaping lives. What makes the book stand out is its relative balance; itโs not a screed, nor naรฏvely hopeful. It nicely captures the tension between human settlement — our love and need to be near the ocean — and the coastโs natural (and unnatural, depending on how you look at it) cycles of change.
Xia is at her best when exploring adaptation and equity. She reminds us that even if emissions stopped today, the ocean will keep rising, and that not all communities have equal means to respond. The stories of engineers, Indigenous leaders, and ordinary residents highlight how resilience and adaptation must be rooted in local realities. I was especially drawn to Xiaโs account of the California Coastal Commission, a wildly controversial agency that wields immense power over the future of the shoreline. Yet it was the commission and its early champions, such as Peter Douglas, who ensured that Californiaโs coast remained open and accessible to all, a decision I consider one of the greatest legislative achievements in modern conservation history.
Thoughtful, accessible, and rooted in the coast we all care about, California Against the Sea challenges us to ask a pressing question: how can we live wisely, and with perspective, at the edge of a changing world?
Kim Stanley Robinsonโs The High Sierra: A Love Story is an expansive, heartfelt tribute to Californiaโs most iconic mountain range. Because of the Sierraโs vast internal basins, which are missing from many of the worldโs other great mountain ranges, Robinson argues they are among the best mountains on Earth. His point is hard to refute. He makes a convincing case that the Sierra Nevada may be the greatest range in the world, formed from the planetโs largest single block of exposed granite and lifted over millions of years into its dramatic present shape.
Blending memoir, geology (my favorite part of the book), and adventure writing, Robinson chronicles his own decades of exploration in the Sierra Nevada while tracing the forces — glacial, tectonic, and emotional, that shaped both the landscape and his own life.
Considered one of our greatest living science fiction writers (Iโve read Red Mars — long, but superb — and am currently reading The Ministry for the Future — the opening chapter is gripping and terrifying), Robinson might seem an unlikely guide to the granite heights of California. Yet reading The High Sierra: A Love Story reveals how naturally his fascination with imagined worlds extends into this very real one. The drama of the range, with its light, vastness, and sculpted peaks and basins, feels like raw material for his other universes.
The Dreamt Land is a portrait of Californiaโs Central Valley, where the control of water has defined everything from landscape to power (power in the form of hydroelectric energy and human control over who gets to shape and profit from the valleyโs vast resources). Blending investigative journalism, history, and memoir, Arax explores how the stateโs rivers, dams, and aqueducts turned desert into farmland and how that transformation came at immense ecological and social cost.
Iโve read several Arax books, but this one is my favorite. Heโs one of the finest writers California has produced. He writes with passion and clarity, grounding his ideas in decades of firsthand experience with Californiaโs land and water. His focus on the fertile Central Valley, where he grew up as a reporter and farmerโs son, gives the book both intimacy and authority, revealing how decisions about water shape not just the landscape but the people who depend on it. There are heroes and villains, plenty of the latter, and all of them unmistakably real. Yet Araxโs prose is so fluid and eloquent that youโll keep reading not only for the story, but for the sheer pleasure of his writing.
If youโre at all fascinated by Californiaโs wild geology — and it truly is wild, just ask any geologist — this classic from one of the finest nonfiction writers alive is a must-read. McPhee takes readers on a geological road-trip through California, from the uplifted peaks of the Sierra Nevada to the fault-riven terrain of the San Andreas zone. He teams up with UC Davis geologist Eldridge Moores to explain how oceanic plates, island arcs, and continental blocks collided over millions of years to โassembleโ the landmass we now call California. His prose is classic McPhee: clean, vivid, perhaps sometimes overly technical, as he turns terms like โophioliteโ and โbatholithโ into aspects of a landscape you can picture and feel.
What makes the book especially rewarding, especially for someone interested in earth systems, mapping, and the deep time, is how McPhee seamlessly links everyday places with deep-time events. Youโll read about gold-rush mining camps and vineyard soils, but all of it is rooted in tectonics, uplift, erosion, and transformation. Iโve gotten some of my favorite stories here on California Curated from the pages of this book. It can be ponderous at times, but youโll not regret giving it a try.
Obi Kaufmanโs California Lands Trilogy is one of the most visually stunning and ambitious projects in California natural history publishing. Beginning with The Forests of California, the first of three volumes that reimagine the state not through its highways or cities but through its living systems, Kaufman invites readers to see California as a vast and interconnected organism, a place defined by its natural rhythms rather than human boundaries. Each book is filled with delicate watercolor maps and diagrams by the author himself. The result is part art book and part ecological manifesto, a celebration of the interconnectedness of Californiaโs natural world. Kaufmanโs talents as an artist are breathtaking. If he ever offered his original watercolors for sale, Iโd be among the first in line to buy them. Taken together, the series forms a panoramic vision of the stateโs natural environments.
That said, Kaufmanโs books can be dense, filled with data, maps, and cross-references that reward slow reading more than quick browsing. If Iโm honest, I tend to dip in and out of them, picking them up when Iโm bored or need a break from the latest political bombshell. Every page offers something to linger over, whether itโs a river system painted like a circulatory map or a meditation on the idea of rewilding. For anyone fascinated by Californiaโs natural systems, all Kaufmanโs Field Atlases are invaluable companions endlessly worth revisiting.
My first job out of college was with the Department of the Interior in Washington, D.C., by far by the nation’s largest land management agency. A big part of that work involved traveling to sites managed by Interior across the country. I came to understand just how vast Americaโs public lands are and how much of that expanse, measured in millions of acres, is under the care of the Bureau of Land Management (BLM).
Josh Jackson takes readers on a road trip across Californiaโs often overlooked public wilderness, focusing on the lands managed by the BLM, an agency once jokingly referred to as the Bureau of Livestock and Mining. He shows how these so-called โleftover landsโ hold stories of geology, Indigenous presence, extraction, and conservation.
His prose and photography (he has a wonderful eye for landscapes) together invite the reader to slow down, look closely at the subtleties of desert mesas, sagebrush plains, and coastal bluffs, and reckon with what it means to protect places many people have never heard of. His use of the environmental psychology concept of โplace attachmentโ struck a chord with me. The theory suggests that people form deep emotional and psychological bonds with natural places, connections that shape identity, memory, and a sense of belonging. As a frequent visitor to the Eastern Sierra, especially around Mammoth Lakes and Mono Lake, I was particularly drawn to Jacksonโs chapter on that region. His account of the lingering impacts of the Mining Act of 1872, and how its provisions still allow for questionable practices today, driven by high gold prices, was eye-opening. I came away with new insights, which is always something I value in a book.
I should mention that I got my copy of the book directly from Josh, who lives not far from me in Southern California. We spent a few hours at a cafe in Highland Park talking about the value and beauty of public lands, and as I sat there flipping through the book, I couldnโt help but acknowledge how striking it is. Part of that comes from Heyday Booksโ exceptional attention to design and production. Heyday also publishes Obi Kaufmanโs work and they remain one of Californiaโs great independent publishers. But much my appreciation for the book also comes from from Jackson himself, whose photographs are simply outstanding.
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What makes this book especially compelling is its blend of adventure and stewardship. Jackson doesnโt simply celebrate wildness; he also lays out the human and institutional connections that shape (and threaten) these public lands, from grazing rights to mining to climate-change impacts. Some readers may find the breadth of landscapes and stories a little ambitious for a first book, yet the richness of the journey and the accessibility of the writing make it a strong addition for anyone interested in Californiaโs endless conflict over land use: what should be used for extraction and what should be preserved? While I donโt fully agree with Jackson on the extent to which certain lands should be preserved, I still found the book a wonderful exploration of that question.
Amy Tanโs The Backyard Bird Chronicles is a charming and unexpectedly personal journal of bird-watching, set in the yard of Tanโs Bay Area home. Tan is an excellent writer, as one would expect from a wildly successful novelist (The Joy Luck Club, among others). But she also brings a curiosity and wonder to the simple act of looking across oneโs backyard. I loved it. Who among us in California doesnโt marvel at the sheer diversity of birds we see every day? And who hasnโt wondered about the secret lives they lead? A skilled illustrator as well as a writer, she studies the birds she observes by sketching them, using art as a way to closely connect with the natural world around her.
What begins as a peaceful retreat during the Covid catastrophe becomes an immersive odyssey of observation and drawing. Tan captures the comings and goings of more than sixty bird species, sketches their lively antics, as she reflects on how these small winged neighbors helped calm her inner world when the larger world felt unsteady.
My only quibble is that I was hoping for more scientific depth; the book is more of a meditation than a field study. Still, for anyone who loves birds, sketching, or the quiet beauty of everyday nature, it feels like a gentle invitation to slow down and truly look.
California is the most botanically diverse state in the U.S. (by a long shot), home to more than 6,500 native plant species, about a third of which exist nowhere else on Earth. Jared Farmerโs Trees in Paradise: A California History follows four key tree species in California: the redwood, eucalyptus, orange, and palm. Through these examples, Farmer reveals how Californians have reshaped the stateโs landscape and its identity. Itโs rich in scientific and historical detail. I have discovered several story ideas in the book for California Curated and learned a great deal about the four trees that we still see everywhere in the California landscape.
In telling the story of these four trees (remember, both the eucalyptus and the palm were largely brought here from other places), Farmer avoids easy sentimentality or harsh judgment, instead exploring how the creation of a โparadiseโ in California came with ecological costs and profoundly shaped the stateโs identity. While the book concentrates on those four tree categories, its detailed research and insight make it a compelling read for anyone interested in the stateโs environment, history, and the ways people shape and are shaped by land.
Southern Californiaโs beaches are a miracle. More than just landscapes, theyโre cultural treasures. In movies, ads, and music, the coastline often feels like its own character. To many of us who live here, the coastline is not just a place to swim or sunbathe but a symbol of freedom, fun, and the stateโs enduring connection to the Pacific Ocean.
And let’s face it, the beach would not be the beach without sand.
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I didnโt realize how essential sand is until I read Vince Beiserโs The World in a Grain. It quickly became one of my favorite nonfiction books in recent years … and I read a lot of nonfiction. Think about it: without sand, there would be no roads, no skyscrapers, no glass. That means no windows, no windshields, no microscopes or telescopes. No fiber-optic cables. No computer chips, since silicon, the foundation of modern technology, is essentially refined sand. The list is endless. I get that it’s not all beach sand per se, but that’s a quibble.
However, that’s not what I want to focus on here. What struck me, as I was walking along the beach the other day, was a simpler question: where does all the sand on Southern Californiaโs beaches actually come from?
San Gabriel Mountains (Photo: Erik Olsen)
Well, put yourself for a moment on the beach in Southern California. No shoes. It turns out most of the grains between your toes actually began their journey high in the mountains above LA, on craggy slopes far from the shore. Mostly, we are talking about the San Gabriel Mountains and other peaks in the Transverse Ranges that run east-west across Southern California. The rugged, crumbling peaks are made of granite and other crystalline rocks rich in quartz, feldspar, and mica. Through the relentless process of erosion, wind and rain loosen these minerals, which tumble into streams and rivers, such as the San Gabriel and Santa Ana and are carried out to sea. During storms, torrents of sediment rush downhill toward the coast, and that’s where ocean currents take over.
This region where wave action dominates is called the littoral zone (no, not the literal zone), and it is where sand gets pushed around through a process known as longshore drift. Waves arriving at an angle push sediment along the shore, creating a conveyor belt that can carry grains for miles.
Lifeguard tower in Southern California (Photo: Erik Olsen)
In Southern California, this natural process has been reshaping the shoreline for thousands of years, constantly adding sand to some beaches while stripping it away from others. A lot has changed recently though (I mean “recent” in geologic terms). Humans, as we often do, have f*cked things up a bit, changing the nature of our beaches since the late 1800s. The piece I wrote recently about the Wedge in Newport is a good example. Breakwaters and other “shoreline armoring” built along our coast have altered the movement of sand, sending much of it into deep water where it is lost.
Dams have also cut off a huge portion of sediment that would once have reached the coast, reducing Southern Californiaโs natural sand supply by nearly half. To make up the difference, beach managers spend millions each year dredging sand from offshore deposits or harbor entrances and pumping it onto the shore. We’ve been doing this for nearly a century. Between 1930 and 1993, more than 130 million cubic yards of sand were placed on Southern California beaches, creating wide stretches like Santa Monica and the Silver Strand that are much larger today than they would have been naturally. And if you think this is a temporary thing, forget it. With climate change driving stronger storms and rising seas, the need to keep replenishing sand is only going to grow.
Big Tujunga Dam in Southern California (Photo: Erik Olsen)
For decades, geologists believed that rivers supplied as much as 90 percent of Californiaโs beach sand. That view has shifted. Research from Scripps Institution of Oceanography shows that coastal cliffs also play a huge role on some beaches. Along the stretch from Dana Point to La Jolla, cliff erosion has been shown to contribute about half of the beach-sized sediment, and in some places up to 68 percent. This is especially true in dry years, when rivers deliver less. Still, on a statewide scale, rivers remain the main suppliers of sand. Studies from the California Coastal Sediment Management Workgroup show that, under present conditions, rivers account for about 90 percent of sand reaching Southern California beaches, with bluff erosion contributing roughly 10 percent.
Littoral cells in Southern California (Source: California Coastal Commission)
The sandโs story does not end at the shoreline. Californiaโs coast is divided into littoral cells, essentially self-contained systems with their own sand sources, transport pathways, and sinks. Most sand in Southern California moves north to south, carried by waves arriving from the northwest. Eventually, much of it is lost into submarine canyons like Mugu, Newport, and Redondo, where it drops into deep water and exits the system.
Beach sand can also come from more subtle sources. Shell fragments from marine life, volcanic ash from distant eruptions, and even windblown desert dust can mix into the sediment. Perhaps not surprisingly, in recent decades, scientists have discovered another ingredient in our sand: plastic. Studies at Point Reyes and Golden Gate National Parks found an average of about 140 microplastic particles per kilogram of beach sand, which works out to roughly 50 pieces in a single measuring cup. Even beaches farther south, like Cabrillo, average nearly 40 pieces per kilogram.
Staff collect sand samples at Cabrillo National Monument. Testing revealed that Cabrillo sand had the lowest average concentration of microplastics of all of the West Coast parks studied. Point Reyes and Golden Gate had the highest. (Photo: National Park Service)
Offshore sediment cores show that microplastic deposition has doubled every 15 years since the 1940s, with most fragments being synthetic fibers shed from clothing. These findings show that Californiaโs sand is no longer entirely natural; it now carries the pernicious imprint of modern consumer life, with fragments of plastic woven into its mix of minerals and shells. Interestingly, the concentration of microplastics off the coast of California, where researchers carried out their studies, appears to be lower than in many other parts of the world. โIf they were doing the same thing in the Yellow Sea in China, right outside some of the big rivers like the Yangtze and Yellow River, the concentrations would probably be huge and cause adverse effects,โ University of Michigan eco-toxicologist Allen Burton told Wired Magazine.
But look, the chance to walk or run on the beach is one of the real gifts of living in California. The sand that sticks to your towel, finds its way into your shoes, or gets stuck into your hair has traveled a long, remarkable journey to reach the shore. Itโs true that some of it now includes plastic, which is unfortunate, but that doesnโt diminish the joy of being at the beach. In a world where so much feels fast, fleeting, and digital, thereโs something really cool and satisfying about putting your toes in the sand, a remarkable substance that is totally crucial to modern civilization, yet which is also timeless and ancient and part of the natural world around us.
Having spent much of my youth in Newport Beach, my life was shaped by the ocean. I spent countless days in the surf, bodyboarding, bodysurfing, or playing volleyball on the sand with friends. When a southern storm rolled through, weโd rush to Big Corona and throw ourselves into the heavy swells, often getting slammed hard and learning deep respect for the ocean, a respect that I still harbor today. Sometimes the waves were so large they were genuinely terrifying, the kind of surf that would have made my mother gasp, had this not been an era when parents rarely knew what their kids were doing from dawn to dusk. That freedom, especially in Southern California, made the ocean feel like both a playground and a proving ground.
Across the channel at the Newport jetty was where the action was most intense. The surf was bigger, louder. We sat on the sand and held back, watching the brave and sometimes the foolish throw themselves into the water. That place, then and now, is called the Wedge.
The Wedge in Newport Beach, California (Photo: Alex Verharst 2016)
There is something unforgettable about the Wedge and the way its waves crash with such raw force. Sometimes they detonate just offshore, sending water skyrocketing into the air; other times they slam thunderously against the sand, eliciting groans and whoops from bystanders. The waves behave strangely at the Wedge, smashing into one another, often combining their force, and creating moments of exquisite chaos.
These colliding waves are what make the place both spectacular and dangerous, the result of a unique mix of physics and geology that exists almost nowhere else on earth. That combination has made it, to this day, one of the worldโs most famous surf and bodysurfing spots. If you want a glimpse of what I mean, just search YouTube, where the insanity speaks for itself. This compilation is from earlier this year.
The Wedgeโs origin story begins in the 1930s, when the U.S. Army Corps of Engineers extended Newport Harborโs West Jetty to protect the harbor mouth from sand buildup and currents. What no one anticipated was that this angled wall of rock would create a perfect mirror for waves arriving from the south and southwest. Instead of dispersing, these waves slam into the jetty and reflect diagonally back toward the shore. The reflected energy doesnโt dissipate, it collides with the next incoming wave. When the two wave crests line up in phase, their energies combine, and the result is a much steeper, taller, and more powerful wave. In physics this is known as constructive interference: two sets of energy stacking into a single, towering peak.
This wave-doubling effect only works under specific conditions. Long-period south swells, often generated by hurricanes off Mexico or storms deep in the South Pacific, line up nearly parallel to the jetty. Their orientation means maximum contact and reflection. Surfers and bodysurfers describe the result as a pyramid-shaped breaker, or wedge, rising steeply before collapsing with extraordinary force. On the biggest days, these waves can reach 20 to 30 feet, twice the size of surrounding surf.
Crowds gather to watch the carnage at The Wedge in Newport Beach (Photo by D Ramey Logan)
Geology and geography make the situation even more dramatic. The seafloor near The Wedge slopes upward very steeply into a narrow strip of beach. Instead of allowing waves to break gradually, the bathymetry forces them to jack up suddenly, creating a thick lip that pitches forward into shallow water. It’s called a shorebreak, and man, they can be dangerous. More on that in a moment.
Unlike classic point breaks such as Malibu, where waves peel cleanly along a gradual reef, The Wedge produces brutal closeouts: vertical walls of water that crash all at once, leaving no escape route.
It actually can get worse. After each wave explodes on the beach, the backwash races seaward, colliding with the next incoming swell and adding more turbulence. Surfers call it chaos; lifeguards call it dangerous, even life-threatening. Spinal injuries, broken bones, and concussions are common at The Wedge. By 2013, the Encyclopedia of Surfing estimated that the Wedge had claimed eight lives, left 35 people paralyzed, and sent thousands more to the hospital with broken bones, dislocations, and other traumaโmaking it the most injury-prone wave break in the world. A 2020 epidemiological survey places The Wedge among the most lethal surf breaks globally (alongside Pipeline and Teahupoโo), largely due to head-first “over the falls” impacts on the shallow sea floor.
The Wedge in Google Maps
Interesting fact: Long before the Wedge was built, the waves pounding that corner of the Newport Beach jetty were already fierce. In 1926, Hollywood icon John Wayne (then still Marion Morrison) tried bodysurfing there while he was a USC football player. He was slammed into the sand, shattering his shoulder and ending his athletic scholarship. The accident closed the door on his football career but opened the one that led him to Hollywood stardom.
Oceanographers have studied the physics behind the Wedgeโs unique surfbreak in broader terms. Research into wave reflection and interference confirms what locals have known for decades: man-made structures like jetties can redirect swell energy in ways that amplify, rather than reduce, wave height. Studies on steep nearshore bathymetry show how sudden shoaling increases the violence of breaking waves. The Wedge combines both effects in one location, making it a rare and extreme case study in coastal dynamics. In other words, yes, it’s gnarly.
Of course, with all that danger comes spectacle, and when the Wedge is firing, itโs not unusual for hundreds of spectators to line the sand and jetty to watch. In August 2025, the California Coastal Commission approved plans for a 200-foot ADA-compliant concrete pathway and a 10-foot-wide viewing pad along the northern jetty, designed to make the experience safer and more inclusive. The project will provide better access for people using wheelchairs, walkers, and strollers, while also giving life guards and first responders improved vantage points when the surf turns chaotic.
I still get to the Wedge on occasion to watch the carnage. And while in my younger years, I might have ventured out to catch a wave or two if the conditions were relatively mellow, today, I prefer the view from shore, leaving the powerful surf to the younger bodysurfers hungry for a rush.
Itโs time for California to put people back in the deep. A human-occupied submersible belongs in California waters, and weโve waited long enough.
For decades, the state had a strong human-occupied submersible presence, from Navy test craft in San Diego to long-serving civilian science HOVs like the Delta. Those vehicles have been retired or relocated, leaving the West Coast without a single home-based, active human-occupied research submersible (I am not counting OceanGate’s Titan sub for numerous reasons, like the fact it was based in Seattle, but foremost is it was not “classed,” nor was it created for scientific use). Restoring that capability would not only honor Californiaโs legacy of ocean exploration but also put the state back at the forefront of direct human observation in the deep sea. The time has come.
Side note: Iโve had the rare privilege of diving beneath the waves in a submersible three times in three different subs, including one descent to more than 2,000 feet with scientists from the Woods Hole Oceanographic Institution. Without exaggeration, it stands among the greatest experiences of my life.
The United States once had a small fleet of working research HOVs. Today it has essentially one deep-diving scientific HOV in regular service: Alvin, operated by Woods Hole Oceanographic Institution (WHOI) for the National Deep Submergence Facility. Alvin is magnificent, now upgraded to reach 6,500 meters, but it is based on the Atlantic (in Massachusetts) and scheduled years in advance at immense cost.
The human-occupied submersible Alvin surfaces during the 2004 โMountains in the Seaโ Expedition, returning from a dive to explore deep seamount habitats teeming with corals, sponges, and other rarely seen marine life. (Photo: NOAA, Public Domain)
It helps to remember how we got here. The Navy placed Alvin in service in 1964, a Cold War investment that later became a pillar of basic research, investigating hydrothermal vents, shipwrecks and underwater volcanoes, among many, many other accomplishments. Over six decades of safe operations, Alvin has logged thousands of dives and undergone multiple retrofits, each expanding its depth range. Now rated to 6,500 meters, it can reach 98 percent of the ocean floor. WHOI’s partnership model with the Navy and universities shows exactly how public investment and science can reinforce each other. But Alvin is based on the East Coast: all that capability, history, and expertise is thousands of miles away. California needs its own Alvin. Or something even better…and perhaps cheaper. Though by cheaper I do not mean less safe.
For a time, California actually had multiple HOVs. The Navy fielded sister craft to Alvin, including Turtle and Sea Cliff. Both Turtle and Sea Cliff spent their careers with Submarine Development Group ONE in San Diego. Turtle was retired in the late 1990s, and Sea Cliff, launched in 1968 and later upgraded for greater depths, also left service by the end of that decade, ending the Navyโs home-ported HOV presence on the West Coast.
On the Atlantic side, Harbor Branchโs two Johnson Sea Link HOVs supported science and search-and-recovery work for decades before the program ended in 2011 due to funding constraints and shifting research priorities. Iโve interviewed renowned marine biologist Edith Widder several times, and she often speaks about how pivotal her dives in the Johnson Sea Link submersibles were to her career studying animal bioluminescence.
“Submersibles are essential for exploring the planetโs largest and least understood habitat, ” Widder told me. “A human-occupied, untethered submersible offers an unmatched window into ocean life, far surpassing what remotely operated vehicles can provide. ROVs, with their noisy thrusters and blazing lights, often scare away marine animals, and even the most advanced cameras still canโt match the sensitivity of the fully dark-adapted human eye for observing bioluminescence.”
In the central Pacific, the University of Hawaiสปiโs HURL operated Pisces IV and V for much of the 2000s and 2010s, then suspended operations amid funding and ship transitions. Through attrition and budget choices, the working U.S. fleet shrank from a handful to essentially one deep-diving research HOV today.
Manned submersibles are costly to build and operate, and they demand specialized crews, maintenance, and support ships or platforms. Itโs easy to list reasons why California shouldnโt invest in a new generation of human-occupied subs. But that mindset has kept us out of the deep for far too long. Itโs time to turn the conversation around and recognize why having one here would be a transformative asset for science, education, and exploration.
The Seacliff and Turtle submersibles (Photo: U.S. Naval History and Heritage Command photo. Public Domain)
Californiaโs own human-occupied sub legacy is short, but notable. In addition to the Navy submersibles noted above, the Delta submersible, a compact, ABS-class HOV rated to about 1,200 feet, operated from Ventura and later Moss Landing, supporting dozens of fishery and habitat studies from the Southern California Bight to central California. Built by Delta Oceanographics in Torrance, Delta dives in the mid-1990s produced baseline data that still underpin rockfish management, MPA assessments, and predictive habitat maps. The subโs ability to place scientists directly on the seafloor allowed for nuanced observations of species behavior, habitat complexity, and human impacts that remote tools often miss. Many of these datasets remain among the most detailed visual records of Californiaโs deeper reef ecosystems.
The Monterey Bay Aquarium Research Institute (MBARI) operates a world-class research fleet with a robust remotely operated vehicle (ROV) program, but no human-occupied vehicleโa strategic decision the institute made years ago in favor of robotics over direct human dives. (Photo: Erik Olsen)
In the late 1990s, the program shifted north to Moss Landing, where it was operated in partnership with the Monterey Bay Aquarium Research Institute (MBARI) and other institutions. At the time, MBARI was still in the early years of exploring human-occupied vehicles, like Bruce Robisonโs experience piloting the Deep Rover HOV in Monterey Canyon in 1985. To many at MBARI, human occupancy in submersibles began to seem more like a luxury than a necessity. If the goal was to maximize scientific output and engineering innovation, remotely operated vehicles offered longer bottom times, greater payload capacity, and fewer safety constraints. That realization drove MBARI to invest heavily in ROV technology, setting the stage for a long-term move away from human-occupied systems.
Which leads us to the present moment: Californiaโs spectacular coast faces mounting environmental threats, just as public interest in ocean science wanes. And yet, we have no human-occupied research submersible, no way for scientists or the public to directly experience the deep ocean that shapes our stateโs future.
The Delta submersible, once a workhorse of Californiaโs deep-sea research with over 5,800 dives, operated from Ventura and later Moss Landing between the 1980s and 2000s. Sold in 2011 in a non-functional state, it remains out of serviceโsymbolizing the end of the stateโs home-ported human-occupied submersible era.
Look, robots are incredible. MBARIโs ROVs and AUVs set global standards, and they should continue to be funded and expanded. But if you talk to veteran deep-sea biologists and geologists, they will tell you that being inside the environment changes the science.
Dr. Adam Soule, chief scientist for Deep Submergence at the Woods Hole Oceanographic Institution (WHOI) agrees, โHaving a human presence in the deep sea is irreplaceable. The ability for humans to quickly and efficiently process the inherently 3D world around them allows for really efficient operations and excellent sampling potential. Besides, there is no better experience for inspiring young scientists and for ensuring that any scientist can get the most out of unmanned systems than immersing themselves in the environment.โ
Some of our most prominent voices are also speaking out about the need to explore the ocean. I recently produced an hour-long episode of the PBS science program NOVA and one episode was about the new generation of submersibles being built right now by companies like Florida-based Triton Submarines. I had the privilege of talking to filmmaker and ocean explorer James Cameron, who was adamant that human participation in ocean exploration is critical to sustaining public interest and political will.
“The more you understand the ocean, the more you love the ocean, the more you’re fascinated by it, and the more you’ll fight to protect it,” Cameron told me.
The author with James Cameron in front of his submersible the Deepsea Challenger. (Erik Olsen)
Human eyes and brains pick up weak bioluminescence out of the corner of vision, pivot to follow a squid that just appeared at the edge of a light cone, or decide in the moment to pause and watch a behavior a diving team has never seen before. NOAAโs own materials explain the basic value of HOVs this way: you put scientists directly into the natural deep-ocean environment, which can improve environmental evaluation and sensory surveillance. Presence is a measurement instrument.
California is exactly where that presence would pay off. Think about Davidson Seamount, an underwater mountain larger than many national parks, added to the Monterey Bay National Marine Sanctuary because of its ancient coral gardens and extraordinary biodiversity. We know this place mostly through ROVs, and we should keep using them, but a California HOV could carry sanctuary scientists, MBARI biologists, and students from Hopkins Marine Station or Scripps into those coral forests to make fine-scale observations, sample with delicacy, and come home with stories that move the public. Put a student in that viewport and you create a career. Put a donor there and you create a program.
A time-lapse camera designed by MBARI engineers allowed researchers to observe activity at the Octopus Garden between research expeditions. (Photo: MBARI)
Cold seeps and methane ecology are another natural fit. Off Southern California and along the borderlands there are active methane seep fields with complex microbial and animal communities. Recent work near seeps has even turned up newly described sea spiders associated with methane-oxidizing bacteria, a striking reminder that the deep Pacific still surprises us. An HOV complements ROV sampling by letting observers linger, follow odor plumes by sight and instrument, and make rapid, in-situ decisions about fragile communities that are easy to miss on video. That kind of fine-grained exploration connects directly to Californiaโs climate priorities, since methane processes in the ocean intersect with carbon budgets.
There are practical use cases all over the coast. A California HOV could support geohazard work on active faults and slope failures that threaten seafloor cables and coastal infrastructure. It could conduct pre- and post-event surveys at oil-and-gas seep sites in the Santa Barbara Channel to ground-truth airborne methane measurements. It could document deep-water MPA effectiveness where visual census by divers is impossible. It could make repeated visits to whale falls, oxygen minimum zone interfaces, or sponge grounds to study change across seasons.
An autonomous underwater craft used to map DDT barrels on the seafloor off California. (Photo: Scripps Institution of Oceanography at U.C. San Diego)
It could also play a crucial role in high-profile discoveries like the recent ROV surveys that revealed thousands of corroding barrels linked to mid-20th-century DDT dumping off Southern California. Those missions produced stark imagery of the problem, but a human-occupied dive would have allowed scientists to make on-the-spot decisions about barrel sampling, trace-chemical measurements, and sediment core collection, as well as to inspect surrounding habitats for contamination impacts in real time. The immediacy of human observation could help shape quicker, more targeted responses to environmental threats of this scale.
And itโs not just the seafloor that matters. Some of the most biologically important parts of the ocean lie well above the bottom. The oceanโs twilight zone, roughly 200 to 1,000 meters deep, is a vast, dimly lit layer that contains one of the planetโs largest reservoirs of life by biomass. (My dive with WHOI was done to study the ocean’s twilight zone). Every day, trillions of organisms participate in the planetโs largest migration, the diel vertical migration, moving up toward the surface at night to feed and returning to depth by day. This zone drives global carbon cycling, supports commercial fish stocks, and is home to remarkable gelatinous animals, squid, and deepwater fishes that are rarely seen in situ.
Launching the Triton 3300/3 (Photo: Erik Olsen)
The Triton 3300/3โs 1,000-meter depth rating (I’ve been in one twice) puts the entire twilight zone within reach, enabling direct observation of these daily movements, predator-prey interactions, and delicate species that often disintegrate into goo in nets. Human presence here allows scientists to make real-time decisions to follow unusual aggregations, sample with precision, and record high-quality imagery that captures how this midwater world works, something uncrewed systems alone rarely match.
It could even serve as a classroom at depth for carefully designed outreach dives, giving educators footage and first-person accounts that no livestream can quite match. Each of these missions is stronger with people on site, conferring, pointing, deciding, and noticing.
While Monterey Bay would be a natural fit because of MBARI, Hopkins, and the sanctuaryโs deepwater treasures, Southern California could be just as compelling. Catalina Island, with its proximity to submarine canyons, coral gardens, and cold seeps of the Southern California Bight, offers rich science targets and the existing facilities of USCโs Wrigley Marine Science Center. Los Angeles or Long Beach would add the advantage of major port infrastructure and a vast urban audience, making it easier to combine high-impact research with public tours, donor events, and media outreach. And San Diego with its deep naval history, active maritime industry, Scripps Institution of Oceanography, and proximity to both U.S. and Mexican waters, could serve as a southern hub for exploration and rapid response to discoveries or environmental events. These regions could even share the vehicle seasonally: Monterey in summer for sanctuary work, Catalina/LA or San Diego in winter for Southern California Bight missions, spreading both benefits and funding responsibility.
The author in front of the Triton 3300/3 in the Bahamas (Photo: Erik Olsen)
For budgeting, a proven benchmark is the Triton 3300/3, a three-person, 1,000-meter (3,300-foot) human-occupied vehicle used widely in science and filming. New units are quoted in the four to five million dollar range, with recent builds coming in around $4โ4.75 million depending on specifications. Beyond the vehicle, launch and recovery systems such as a 25โ30-ton A-frame or LARS and the deck integration required for a suitable support ship can run into the high six to low seven figures. Modern acrylic-sphere subs like the Triton are designed for predictable, minimized scheduled maintenance, but budgets still need to account for annual surveys, battery service, insurance, and ongoing crew training. Taken together, a California-based HOV program could be launched for an initial capital investment of roughly $6โ7 million, with operating budgets scaled to the number of missions each year. So, not cheap. But doable for someone of means and purpose and curiosity. See below.
Who would benefit if California restored this capability? Everyone who already works here. MBARI operates a world-class fleet of ROVs and AUVs but has no resident HOV. Scripps Institution of Oceanography, Hopkins Marine Station, and USCโs Wrigley Marine Science Center train generations of ocean scientists who rarely get the option to do HOV work without flying across the country and waiting for a slot. NOAA and the sanctuaries need efficient ways to inspect resources and respond to events. A west-coast human-occupied research submersible based in Monterey Bay, Catalina, Los Angeles, or San Diego would plug into ship time on vessels already here, coordinate with ROV teams for hybrid dives, and cut mobilization costs for Pacific missions.
A new Triton 660 AVA submersible slips into the turquoise waters of the Bahamas, beginning its first voyage. Built for dives to 660 feet (200 meters), it offers passengers a front-row seat to reefs, shipwrecks, and marine life far beyond normal scuba limits, making it an ideal draw for high-end tourism. (Photo: Erik Olsen)
What would it take? A benefactor and a compact partnership. California has the donors (hello, curious billionaires!), companies, and public-private institutions to do this right. A philanthropic lead gift could underwrite acquisition of a proven, classed HOV and its support systems, while MBARI, Scripps, or USC could provide engineering, pilots, and safety culture within the UNOLS standards that govern HOV operations. No OceanGates. Alvinโs long record shows the model. Add a state match for workforce and student access, and a sanctuary partnership to guarantee annual science priorities, and you have a durable program that serves research, stewardship, and public engagement.
Skeptics will say that robots already do the job. They do a lot of it. They do not do all of it. If the U.S. is content to have only one deep research HOV based on the opposite coast, we will forego the unique perspectives and serendipity that only people bring, and we will keep telling California students to wait their turn or watch the ROV feed from their laptops or phones. California can do better. We did, for years, when the Delta sub spent long seasons quietly counting fish and mapping habitats off Ventura and the Channel Islands. Then that capability faded. If we rebuild it here, we restore a missing rung on the ladder from tidepools to trenches, and we align the stateโs science, climate, and education missions with a tool that is both a laboratory and a conversion experience.
The author at more than 2000 feet beneath the surface of the ocean. (Photo: Erik Olsen)
Start with a compact, 1,000-meter-class HOV that can work daily in most of Californiaโs shelf and slope habitats. Pair it with our ROVs for tandem missions and cinematography of the sub and its occupants in action. Commit a share of dives to student and educator participation, recorded and repackaged for museums and broadcast. Reserve another share for rapid-response science at seeps, landslides, unusual biological events, or contamination crises like the DDT dumpsite. Build a donor program around named expeditions to Davidson Seamount, Catalinaโs coral gardens, and the Channel Islands. Then, if the community wants to go deeper, plan toward a second vehicle or an upgrade path. The science is waiting. The coast is ready. And the case is clear. California should restore its human-occupied submersible fleet.
