Stuck Between a Volcano and a Hard Place (part 2): Politics and Geology Square Off in a Small Town with a Big Problem

I've been more and more concerned about the public damage being done to the scientific community and larger society as politics has swirled like a tornado around global warming, climate change, and pandemics. Trust is eroding in some quarters, and I only see this leading to worse disasters in the years to come (and really, nearly a million Americans dead is a huge disaster, even though it unfolded slowly over two years; just imagine the impact if those people had died all on one day). This damaged social compact between those who do science and the society at large reminded me that it isn't the first time this kind of issue has affected the public, and a few years ago I wrote about it in a two-part series. Here, with some modifications and updates, is part two.

Twin Lakes, above the town of Mammoth Lakes on the edge of the Long Valley Caldera

So what happened in Mammoth Lakes?

In the last post we talked about the titanic explosion at the Long Valley Caldera 760,000 years and tried to comprehend the scale of an event where 150 cubic miles of ash was blown into the atmosphere, covering much of the country. We then fast-forwarded to the near-present day of Mammoth Lakes in the 1980s. When we left the story, geologists were trying to decide what to do at the ski resort town in the face of astounding earthquake swarms, ground level changes, and increased geothermal activity.

It could probably be called a (tragi)comedy of errors. The USGS volcanologists carefully prepared a report to accompany a NOTICE OF POTENTIAL VOLCANIC HAZARD, the lowest level warning in their guidelines. A reporter from the Los Angeles Times figured out what was going on and published a story about the potential volcanic activity the day before the USGS released their report. The geologists got scooped, in other words, and the story became a runaway train in the national media. The government and emergency services personnel who were supposed to get the report and develop a response plan were blindsided by reporters asking them how it felt to be living in a doomed town.

The carefully worded statement from the USGS noted that "available evidence is insufficient to suggest that a hazardous event is imminent", but it was their description of the hazards that caught the attention of reporters and news hosts: rocks falling out of the sky miles from the eruptive vents, hot ash flows melting thick snowpacks and producing dangerous mudflows, and dangerous gases suffocating people. The very manna of the most desired headline: if it bleeds, it leads.

Hot Creek, a geothermal site in the Long Valley Caldera

By some accounts, the damage to the economy of Mammoth Lakes from the media circus may have been worse than an actual volcanic eruption (though no one died). Tourists stayed away in droves, businesses went belly up, and condo projects were abandoned. The business leaders of the town were livid at the geologists for stirring things up and scaring people (although by my reading, their notices were very conservative and carefully worded). They demanded that the geologists stop their campaign of terror/error, accusing them of bad science or something darker. There were even bomb threats (I had forgotten that detail; see the reference at the end of this post).

Warning sign at Horseshoe Lake, one of the carbon dioxide tree-kill sites on Mammoth Mountain.

The geologists could only respond in disbelief. I feel like I would have said something along the lines of "You are sitting on top of an active body of magma that is a few thousand feet from the surface! It would be irresponsible to keep such a thing secret". The geologists stuck to their guns, and the threat level remained at level one, the lowest level of concern, but concern nonetheless.

The business owners and local politicians went up the chain of command. They appealed to the head of the USGS, and his boss, the Secretary of the Interior, a man named James Watt. They may have communicated with then-president Reagan. As far as I can tell, there was intense political pressure from above, and eventually the director of the USGS unilaterally scrapped the warning system. Poof! It was gone. No discussion. It its place would be an informal warning system of quiet communications between geologists and civic leaders.

If this were a Hollywood movie, what happens next would be preordained. Everyone would come back. The skiers would be happily sliding down the slopes, businesses would be taking in money hand over fist, and suddenly out of nowhere there would be a resounding explosion and all hell would break loose as the caldera gives way to a catastrophic eruption that kills the "evil" business leaders because they had been greedy, and a gritty, yet handsome geologist would lead a beautiful woman and her plucky children to safety. Heck, I could see casting someone like, oh, say, Pierce Brosnan as the geologist and Linda Hamilton as the lady. Maybe call it "Dante's Peak" and move the setting to Idaho for some reason.

Yeah, I'd say that casting choice for the geologist was about right. Either one of them....

But that isn't what happened, of course. The molten magma was almost certainly there, but it cooled and solidified instead of continuing to the surface. The earthquake swarms ebbed, but other swarms have taken place over the years, though most have been tectonic in origin (related to faulting rather than magma). Gases from the magma chamber, especially carbon dioxide, have continued to seep from the ground, killing trees and other vegetation in several areas, including Horseshoe Lake (below). The gases actually killed three people a few years ago.  After some years, the USGS established a volcano observatory that monitors Long Valley, and came up with a new warning system, one with four stages, and specific actions to be taken with each. It's based on colors, just like our former Bush-era terrorism warning system. The town's economy slowly recovered. They started building condos again.

Tree kill area at Horseshoe Lake. Carbon dioxide in the soil suffocates the roots and microorganisms necessary for the tree's survival

Some of the political leaders took a bit of action. One of the main concerns was that an eruption would have destroyed the only paved road out of town. No evacuation would have been possible if the highway was blocked off. A few years after the brouhaha, a road appeared at the upper end of town called the Mammoth Lakes Scenic Route. I have to say that as a geologist that I didn't see a whole lot of scenery as I drove this nice paved highway, but I couldn't help but notice that it was exactly where I would have chosen to put an evacuation route (according to Dick Thompson in Volcano Cowboys, the county supervisors responsible were recalled from office for arranging this bit of road-building; it was like an admission that volcanism was actually possible).

Hot Creek, one of the centers of geothermal activity within the Long Valley Caldera.

In the end, one can only say mistakes were made. Some of those mistakes involved a sort of public relations tone deafness, like releasing a volcano warning on the eve of a holiday weekend, but other mistakes were more nefarious.

There were people willing to deny the possibility of a natural catastrophe in order to protect their profit margins. I see too many parallels in today's political (but not scientific) debates over global warming and climate change, and in the willful denial of the Covid pandemic. The geologists had clear evidence of a volcanic threat and the civic response was to deny the evidence and to attack the reputation of the geologists who were trying to do the right thing. There was a threat to the economy of Mammoth Lakes, but the threat was from a geologic process, not those who discovered and analyzed the volcanic hazard. And threatening the lives of the geologists was criminal. And apparently unpunished.

And the media. What to do about the media? Isn't it amazing how media outlets were willing to blow a story way out of proportion in order to gain ratings? Isn't it nice to know that they don't do that sort of thing anymore? And that the internet (which didn't exist as such in 1983) has turned out to be the very model of accurate and measured analysis of stories like this one, despite the possible instant dissemination of incorrect and potentially dangerous information? I'm so glad we live in an age of logic and reason and respect of scientific research.

Oh, I'm sorry. I briefly stepped into "Opposite-world". I'm back now. Science education and science literacy have never been more important in a world where the internet and media are so irresponsible with their analysis of geological hazards. Every time there is another major earthquake or volcanic eruption, I feel like throwing a shoe through the television screen or computer monitor as the talking heads begin babbling. Instead, I do what I can by throwing words out into the internet trying to offer up a more measured explanation of things. But the mostly ignorant talking heads always seem to win people's attention.

Just imagine the outcome if the geologists at Mammoth Lakes were effectively squelched, no warnings were ever given, and a volcanic eruption had actually occurred. Beyond the devastation, just imagine the scapegoating that would have happened in the aftermath. In Italy such a situation led to prison terms for half a dozen geologists who failed to predict a deadly earthquake (they have since been released).

We can do better than this. Especially those in the news business who are responsible in times of emergency for providing us with reasoned assessments, not sensationalist drabble. When the crisis is over, they can go back to their manic headlines about the personal lives of the stars.

You can read the original post from 2015 here: https://geotripper.blogspot.com/2015/02/the-sierra-beyond-yosemite-politics-and.html

----------------------------
Although aspects of this story of the events at Mammoth Lakes and the Long Valley Caldera are drawn from my memory, I reviewed and confirmed many of the details in the excellent book called "The Volcano Cowboys: the Rocky Evolution of a Dangerous Science" by Dick Thompson (St. Martin's Press, 2002). Check it out, it's a fascinating account of the lives and activities of volcanologists.

A Landscape as Bizarre as They Come: The Volcanic Tableland of the Eastern Sierra Nevada

The Volcanic Tableland, with the White Mountains beyond.

There is a bizarre landscape on the far side of the Sierra Nevada between Bishop and Mammoth Lakes. It's not one of stark beauty exactly, it's barren and covered by little more than sagebrush. It's got few roads or trails, primarily because very little of this landscape is of much use to anybody. From above, the surface is riddled with scarps and grabens from numerous faults. This is a broken-up land. It's not...normal.

Source: US Geological Survey

The surface of this landscape isn't "right" either. There are no dark rich soils here. The underlying rock is pink or white, and so is the weathered soil and debris that covers it. Although the surface has an area of several hundred square miles or more, the underlying rock is remarkably uniform. It is a volcanic rock called rhyolite tuff. And with that name, the explanation for this landscape is revealed: it is the remnant of an ancient disaster beyond imagining.

767,000 years ago, an explosion took about 125 cubic miles of pasty magma from the crust and blew it into the atmosphere. The huge void collapsed inwards, forming an oval-shaped depression 20 miles long, 10 miles wide, and a mile or more in depth. The resulting ash spread far and wide, blanketing the western United States. Measureable deposits can be found in Kansas and Nebraska. But most of the ash came straight down. Some of it refilled the caldera, but much of the remainder buried the regional landscape hundreds of feet deep in hot ash. All life would have been extinguished for miles in every direction.

It is difficult to understand the magnitude of such events. From a human perspective, we have nothing to compare it to. An eruption at Tambora in Indonesia in 1815 produced less than a tenth of the ash as Long Valley, and that was enough to cause global cooling with related summer snowfall, crop failures, and famine across the northern hemisphere. The effects of an eruption the size of Long Valley on modern civilization would be appalling. I've heard it said that modern agricultural production has a month-long lead on consumption demand (No, I can't cite a source. It's a factoid I'm sure I heard or read somewhere). Try to imagine a disruption of agricultural production lasting several years. Governmental and societal structures would collapse, and the death toll would be unimaginable. Humans would no doubt survive, but it would be a dystopian landscape as bad as any sci-fi action movie, and maybe worse.

The only good thing that I can think of to say on this possibility is that studies of calderas like Long Valley or Yellowstone suggest that the eruptions will be predictable on a scale of decades or centuries. There would be time to prepare the eruption, or, however unlikely, geo-engineer the caldera to lessen the intensity and effect of the cataclysm.

What happens when a singular event completely reshapes a landscape? The eruption of Long Valley completely disrupted the drainage patterns of the eastern Sierra Nevada and Owens Valley. The land had to start over. Where there had once been river valleys and canyons, there was now a gaping pit miles wide and long. The evidence suggests that for 600,000 years the caldera depression contained a huge lake similar in plan if not in scale to Crater Lake. Crater Lake has no outlet, with the lake level determined by evaporation and seepage. The Long Valley Lake would have been similar, as no evidence exists for an outlet, at least until around 150,000 years ago.

Source: U.S. Geological Survey

For 600,000 years sediment washed into the basin, slowly filling it. Finally, along the south rim of the caldera near the present day site of Crowley Lake, the basin spilled over. In just 150,000-160,000 years, the Owens River carved a 400-500 foot deep gorge down the surface of the Volcanic Tableland, laying bare the full extent and history of the climactic eruption of the caldera. The rate averages out to about a foot every 400 years, but the rate was probably higher at the beginning. The small creek that flows through the gorge today is a mere shadow of its former self. The Los Angeles Department of Water and Power has co-opted most of the water, but a court order several years ago mandated that a minimum flow must be maintained.

Because the LADWP has utilized the water from the Mono Lake Basin to the north, they have constructed penstocks and pipelines that allow them to produce energy as they transport water down the long slope of the Tablelands. That means access roads, and it is thus easy to visit the gorge, and it is fascinating.

The mounds seen occasionally along the rim are the eroded remnants of fumaroles, where steam would have emanated from the interior of the ashflow, leaving mineral deposits that toughened the rock. The tuff at the rim is relatively soft, but as one walks deeper into the gorge, the rock becomes harder (it tuffons up?). When the hot ash landed, it was hot enough to remelt, forming welded tuff, or ignimbrite. Pieces of pumice caught up in the eruption became flattened and smeared in places.

As the rock cooled, it contracted to form columnar joints. Unlike Devils Postpile, a few miles away on the other side of the crest of the Sierra Nevada, these columns are not vertical. Most columnar jointing is not. The intense fracturing of the rock into these columns aided the Owens River in the carving of the gorge, as the crumbling rock could be quarried by the rushing water much more readily than solid rock.

The columns average six sides, but columns with 4, 5, or 7 sides are occasionally seen.

The Volcanic Tableland and the Owens Gorge are otherworldly, but they provide a hint of how quickly landscapes can adjust to new geological conditions. It took 600,000 years to fill a basin 10 by 20 miles with at least 2,000 feet of sediment, and 150,000 years to carve a 400 foot deep gorge. This is fast by geologic standards, but humans, had they been around this region at the time, would not have noticed much change in course of their lifetimes. Just like we aren't noticing the changes now...

The Sierra Beyond Yosemite: Politics and Geology Square Off in a Town with a Big Problem

Twin Lakes, above the town of Mammoth Lakes on the edge of the Long Valley Caldera

So what happened in Mammoth Lakes?

In the last post we talked about the titanic explosion at the Long Valley Caldera 760,000 years and tried to comprehend the scale of an event where 150 cubic miles of ash was blown into the atmosphere, covering much of the country. We then fast-forwarded to the near-present day of Mammoth Lakes in the 1980s. When we left the story, geologists were trying to decide what to do at the ski resort town in the face of astounding earthquake swarms, ground level changes, and increased geothermal activity.

It could probably be called a (tragi)comedy of errors. The USGS volcanologists carefully prepared a report to accompany a NOTICE OF POTENTIAL VOLCANIC HAZARD, the lowest level warning in their guidelines. A reporter from the Los Angeles Times figured out what was going on, and published a story about the potential volcanic activity the day before the USGS released their report. The geologists got scooped, in other words, and the story became a runaway train in the national media.. The government and emergency services personnel who were supposed to get the report and develop a response plan were blindsided by reporters asking them how it felt to be living in a doomed town.

The carefully worded statement from the USGS noted that "available evidence is insufficient to suggest that a hazardous event is imminent", but it was their description of the hazards that caught the attention of reporters and news hosts: rocks falling out of the sky miles from the eruptive vents, hot ash flows melting thick snowpacks and producing dangerous mudflows, and dangerous gases suffocating people. The very manna of the most desired headline: if it bleeds, it leads.

Hot Creek, a geothermal site in the Long Valley Caldera

By some accounts, the damage to the economy of Mammoth Lakes from the media circus may have been worse than an actual volcanic eruption (though no one died). Tourists stayed away in droves, businesses went belly up, and condo projects were abandoned. The business leaders of the town were livid at the geologists for stirring things up and scaring people (although by my reading, their notices were very conservative and carefully worded). They demanded that the geologists stop their campaign of terror/error, accusing them of bad science or something darker. There were even bomb threats (I had forgotten that detail; see the reference at the end of this post).

Warning sign at Horseshoe Lake, one of the carbon dioxide tree-kill sites on Mammoth Mountain.

The geologists could only respond in disbelief. I feel like I would have said  something along the lines of "You are sitting on top of an active body of magma that is a few thousand feet from the surface! It would be irresponsible to keep such a thing secret". The geologists stuck to their guns, and the threat level remained at level one, the lowest level of concern, but concern nonetheless.

The business owners and local politicians went up the chain of command. They appealed to the head of the USGS, and his boss, the Secretary of the Interior, a man named James Watt. They may have communicated with then-president Reagan. As far as I can tell, there was intense political pressure from above, and eventually the director of the USGS unilaterally scrapped the warning system. Poof! It was gone. No discussion. It its place would be an informal warning system of quiet communications between geologists and civic leaders.

If this were a Hollywood movie, what happens next would be preordained. Everyone would come back. The skiers would be happily sliding down the slopes, businesses would be taking in money hand over fist, and suddenly out of nowhere there would be a resounding explosion and all hell would break loose as the caldera gives way to a catastrophic eruption that kills the "evil" business leaders because they had been greedy, and a gritty, yet handsome geologist would lead a beautiful woman and her plucky children to safety. Heck, I could see casting someone like, oh, say, Pierce Brosnan as the geologist and Linda Hamilton as the lady. Maybe call it "Dante's Peak" and move the setting to Idaho for some reason.

Yeah, I'd say that casting choice for the geologist was about right. Either one of them....

But that isn't what happened, of course. The molten magma was almost certainly there, but it cooled and solidified instead of continuing to the surface. The earthquake swarms ebbed, but other swarms have taken place over the years, though most have been tectonic in origin (related to faulting rather than magma). Gases from the magma chamber, especially carbon dioxide, have continued to seep from the ground, killing trees and other vegetation in several areas, including Horseshoe Lake (below). The gases actually killed three people a few years ago.  After some years, the USGS established a volcano observatory that monitors Long Valley, and came up with a new warning system, one with four stages, and specific actions to be taken with each. It's based on colors, just like the terrorism warning system! The town's economy slowly recovered. They started building condos again.

Tree kill area at Horseshoe Lake. Carbon dioxide in the soil suffocates the roots and microorganisms necessary for the tree's survival

Some of the political leaders took a bit of action. One of the main concerns was that an eruption would have destroyed the only paved road out of town. No evacuation would have been possible if the highway was blocked off. A few years after the brouhaha, a road appeared at the upper end of town called the Mammoth Lakes Scenic Route. I have to say that as a geologist that I didn't see a whole lot of scenery as I drove this nice paved highway, but I couldn't help but notice that it was exactly where I would have chosen to put an evacuation route (according to Dick Thompson in Volcano Cowboys, the county supervisors responsible were recalled from office for arranging this bit of road-building; it was like an admission that volcanism was actually possible).

Hot Creek, one of the centers of geothermal activity within the Long Valley Caldera.

In the end, one can only say mistakes were made. Some of those mistakes involved a sort of public relations tone deafness, like releasing a volcano warning on the eve of a holiday weekend, but other mistakes were more nefarious.

There were people willing to deny the possibility of a natural catastrophe in order to protect their profit margins. I see parallels in today's political (but not scientific) debates over global warming and climate change. The geologists had clear evidence of a volcanic threat and the civic response was to deny the evidence and to attack the reputation of the geologists who were trying to do the right thing. There was a threat to the economy of Mammoth Lakes, but the threat was from a geologic process, not those who discovered and analyzed the volcanic hazard. And threatening the lives of the geologists was criminal.

And the media. What to do about the media? Isn't it amazing how media outlets were willing to blow a story way out of proportion in order to gain ratings? Isn't it nice to know that they don't do that sort of thing anymore? And that the internet (which didn't exist as such in 1983) has turned out to be the very model of accurate and measured analysis of stories like this one, despite the possible instant dissemination of incorrect and potentially dangerous information? I'm so glad we live in an age of logic and reason and respect of scientific research.

Oh, I'm sorry. I briefly stepped into "Opposite-world". I'm back now. Science education and science literacy have never been more important in a world where the internet and media are so irresponsible with their analysis of geological hazards. Every time there is another major earthquake or volcanic eruption, I feel like throwing a shoe through the television screen or computer monitor as the talking heads begin babbling. Instead, I do what I can by throwing words out into the internet trying to offer up a more measured explanation of things. But the mostly ignorant talking heads always seem to win people's attention.

Just imagine the outcome if the geologists at Mammoth Lakes were effectively squelched, no warnings were ever given, and a volcanic eruption had actually occurred. Beyond the devastation, just imagine the scapegoating that would have happened in the aftermath. In Italy such a situation led to prison terms for half a dozen geologists who failed to predict a deadly earthquake (they have since been released).

We can do better than this. Especially those in the news business who are responsible in times of emergency for providing us with reasoned assessments, not sensationalist dribble. When the crisis is over they can go back to their manic headlines about the personal lives of the stars.

----------------------------
Although aspects of this story of the events at Mammoth Lakes and the Long Valley Caldera are drawn from my memory, I reviewed and confirmed many of the details in the excellent book called "The Volcano Cowboys: the Rocky Evolution of a Dangerous Science" by Dick Thompson (St. Martin's Press, 2002). Check it out, it's a fascinating account of the lives and activities of volcanologists.

The Sierra Beyond Yosemite: Exploring One of the World's Largest Volcanic Eruptions...Ever. And a Problem

There is a story I tell on the first day of almost every class I teach. It's about a place filled with the evidence of one of the great explosions in Earth history, near Mammoth Lakes in the eastern Sierra Nevada. The students in the picture above are standing on the edge of a gorge that exposes some aspects of the explosion, but no one place reveals the full magnitude of what happened here. We made a number of stops many miles apart, but it's hard to comprehend the full scale of the blast. It's just too big.

About 760,000 years ago, a magma chamber composed of silica-rich rhyolite magma exploded in a titanic eruption that sent about 150 cubic miles (600 cubic kilometers) of ash across the western United States. Ash layers are still recognizable in places like Kansas and Nebraska, and in the immediate area around the blast, volcanic ash and tuff occur in deposits hundreds of feet thick spread over dozens of square miles. So much material was lofted into the atmosphere that the crust collapsed into a gigantic hole 10 miles (16 km) wide and 20 miles (32 km) long, and thousands of feet deep; it's called the Long Valley Caldera

For me, it took an overflight at 30,000 feet to even begin to see the full scale of the blast. Just about all the landscape in the picture above is covered with volcanic tuff. A freeway climbs the slope on the left side of the picture, but is barely visible. I've added labels in the picture below to highlight the location of the caldera, which was obscured by clouds

In this mini-blog series, we've been exploring the Sierra Nevada beyond the very limiting confines of Yosemite Valley and Yosemite National Park. Our fall field studies trip took us down the Owens Valley and some of the lands east of the Sierra Nevada crest, including this gigantic hole that actually breached the mountain wall. The lower section of the crest allows Pacific storms to blow through, dropping prodigious amounts of snow, especially on Mammoth Mountain, a volcano that developed on the edge of the caldera thousands of years after the climactic blast. Many thousands of years later, it was decided that this was a perfect place to put a ski resort.

The Owens River Gorge on the margin of the Long Valley Caldera.

The caldera filled with water, and for thousands of years there was a lake. Eventually it breached the south edge of the caldera and drained. The resulting Owens River carved a 400 foot deep gorge in a short period of time (above), and the canyon walls provide a marvelous cross-section of the strange volcanic rock.

The edge of the Long Valley Caldera along the Sierra Nevada crest.

The caldera is a stunning place to visit and contemplate, but that's not actually the story I tell my students on the first day of most of my classes. The story concerns an incident at Mammoth Lakes dating from the early 1980s which still has huge implications in the present day. It's about civic responsibility and public safety in the face of deadly geologic hazards, and how geologists found themselves stuck between a volcano and a hard place. The purpose of telling the story to my classes is to highlight the danger of willful geological ignorance.

On May 18, 1980, Mt. St. Helens exploded with unexpected ferocity, killing nearly four dozen people. The U.S. Geological Survey was caught off guard in terms of predicting the moment of the eruption, as they did not yet understand the dynamics of Cascades volcanoes. Only a week or so later, a series of four magnitude 6 earthquakes struck the Mammoth Lakes region, injuring a number of people and causing several million dollars of damage. Many more earthquakes followed, and with the location of the epicenters being within the caldera, the geologists became concerned. They deployed more instruments in the region, and discovered that the floor of the caldera had been rising, some 10 inches between 1979 and 1980. Even more disturbing was the discovery that the earthquakes were migrating, and becoming more shallow, ultimately reaching a mere 7,000 feet or so beneath the surface. New steam vents were opening up (although geothermal activity has always been present). As I say to my students on their first day of class, "You've been geologists for 45 minutes now, what do YOU think was going on?"

The floor of the Long Valley Caldera with Crowley Lake, and Glass Mountain on the far rim of the caldera.

The people of Mammoth Lakes apparently only knew that they were getting a lot of earthquakes. There wasn't a lot of communication between the geologists who were researching the increasing activity and the government and emergency personnel responsible for the safety of the community. I imagine that this occurred (and still occurs today) because of the vast amount of uncertainty involved in predicting geologic events. Who would want to go out on a very long limb and suggest that a town could be on the cusp of a very dangerous, even catastrophic event? You may remember the recent case of geologists in Italy who were jailed because they didn't predict a deadly earthquake.

At the time, the USGS had a warning system in place, with three tiers:

NOTICE OF POTENTIAL HAZARD-Information on the location and possible magnitude of a potentially hazardous geologic condition. However, available evidence is insufficient to suggest that a hazardous event is imminent or evidence has not been developed to determine the time of occurrence.

HAZARD WATCH-Information, as it develops from a monitoring program or from observed precursors, that a potentially catastrophic event of a generally predictable magnitude may occur within an indefinite time (possibly months to years).

HAZARD WARNING-Information (prediction) as to the time, location, and magnitude of a potentially disastrous geologic event.

Give it some thought...given the intense geologic activity, what would you do? Would you notify the civic authorities? Would you go to the media? Is it possible that the media might report the facts as they are known, or would there be a tendency to go overboard on their coverage? Keep in mind the difference between 1983 and the present day when numerous cable news networks have to keep talking 24 hours a day. Or, would you keep things quiet, and hope that the geologic activity would die down without any catastrophes occurring? What happens if you quash your findings, and an eruption takes place? What is your liability in the deaths and injuries that result? Is there an easy answer here?

What would you do?

And what finally happened?

Find out in part 2!

A Gallery of Sierra Nevada Scenes: Part I

Tufa towers on southwest shore of Mono Lake

If Geotripper has been quiet of late, there is a pretty good reason: I've been on the road and off the grid. I may have plenty to say about these scenes later on, but for now I've just gone through the entire collection and picked out the images that caught my eye for some reason or another. In the picture above, it was the one strip of sunlight on the Mono Lake tufa towers in a sky full of smoke. The lake is a vast saline evaporation pond that serves as a temporary stopover for millions of migrating birds.

Bodie Ghost Town

Bodie is a fascinating place. I picked this shot because it shows the close clustering of houses as a hedge against the barrenness of the hills beyond. I visit places like this and realize that you can choose to live comfortably in an equitable climate, or you choose to try and survive in a pitched battle with the elements. Bodie sits at 8,000 feet and suffers horrible bitter winters. It was an outpost of civilization on the edge of a hard wilderness.

Bodie Ghost Town

I still find it hard to believe that a gold mining company wanted to turn the slope behind the town into an open pit mine just a few years ago. Some places should remain as they are.

Owens River Gorge

Owens River Gorge is a little-known corner of the eastern Sierra Nevada that reveals some of the awesome power of earth processes. The 400 feet gorge has walls of rhyolite tuff, erupted in the space of a few hours or a few days in one of the most incredible explosions in earth history. Yellowstone's supervolcano might get all the press, but Long Valley Caldera put 150 cubic miles of hot ash into the atmosphere 760,000 years ago, blanketing the entire American West. Some deposits are found in Kansas and Nebraska. A lake formed in the caldera and eventually overflowed, allowing the Owens River to carve this deep gorge...in only a few hundred thousand years.

Lake Crowley and the Long Valley Caldera

We soon found ourselves standing on the floor of the vast Long Valley Caldera. The eruption caused the crust to collapse in a massive hole 20 miles wide and 11 miles long. The two-mile deep hole was filled with ash and lake sediments over the years, but is still a striking feature. We were standing on one edge of the vast hole, while the mountain ridge in the far distance is the other.

Mt. Tom and Pine Creek

The eastern Sierra Nevada is an astounding wall of rock that developed when the Owens Valley fault graben collapsed and sank, forming a two mile deep valley more than a hundred miles long. Mt. Tom (above) is a 13,652 feet peak rising above Round Valley near Bishop. It lies at the edge of an intrusion of granitic rock and previously existing metamorphic rock. The interaction of the hot fluids around the intrusion produced tungsten minerals that were mined for years in Pine Creek. The mine is currently mothballed.

Minaret Vista

The Minarets lie just west of the Sierra Nevada crest in the vicinity of Mammoth Lakes. The high jagged peaks reveal Triassic metamorphic rocks that developed as an ancient caldera, perhaps similar to  the modern day Long Valley Caldera, collapsed into the underlying magma chamber during a giant eruption. The stunning view is from Minaret Vista on the Sierra crest just above Mammoth Ski Resort.

More to come!

The Airliner Chronicles: A Broken Land of Unspeakable Violence

That's an inflammatory title, and yet in the context of geology it is quite literally true. The land in today's picture is indeed broken, and was the scene of unspeakable violence 760,000 years ago. If such an event were to recur, it's a fair bet that civilization could end up in danger of collapsing into unrecoverable chaos.

Yellowstone National Park gets a lot of attention for being a "supervolcano", and numerous TV documentaries fan the flames of concern about the possibility of a giant eruption in the midst of our country. It's quite true that a full scale explosion like those that have happened three times in the last 2.1 million years could wreak havoc on a wide scale, but Yellowstone hasn't actually had an eruption in 70,000 years.

The proper geological name we geologists use for a "supervolcano" is rhyolite caldera. This works a little better because these calderas are not volcanoes in the normal sense of the word. They are gigantic holes in the ground caused by the collapse of the crust after vast amounts of magma are blasted into the atmosphere. Some calderas were singular mountains at one time (like Mt. Mazama, which collapsed to form Crater Lake in Oregon). Others weren't. They were volcanic centers that included a collection of smaller cones and lava flows. The collapse of giant calderas seem to begin with smaller eruptions that grow in intensity over a time scale measured in decades or centuries. That's why Yellowstone caldera is of somewhat less concern to geologists (that's not to say that lesser eruptions aren't impossible). What is less known to many is that we have more than one recently active rhyolite caldera in the United States; we actually have three. I got a close look at the other two on my plane flight in December.

My flight took a more southerly route than past trips, and as we crossed the crest of the Sierra Nevada, I realized I was flying directly over the north end of the Owens Valley and the Volcanic Tablelands. The Tablelands are the southeastern flank of the Long Valley Caldera, California's version of a "supervolcano". And if anything, it's more dangerous than Yellowstone, if for no other reason than the fact that volcanic activity is ongoing, even though gigantic eruptions like the one that rocked the region 760,000 years ago are unlikely.

The caldera itself was obscured by clouds, but I had a perfect view of the Tablelands, a region adjacent to the caldera that was covered by 400 feet or more of volcanic ash that was so hot when it landed that it welded itself into solid rock. The pink colored rock is called rhyolite tuff. The tuff from this eruption is called the Bishop Tuff.

The scale of the eruption is hard to imagine. For perhaps a week, huge explosions blew ash into the stratosphere. Not a little bit of ash; it amounted to around 150 cubic miles of ash. The ash buried the local landscape under hundreds of feet of hot steaming rock, while some ash deposits have been found as far away as Kansas and Nebraska.

The collapse of the caldera was a stupendous event as well. The hole was around 20 miles long and 10 miles wide, and as much as 1-2 miles deep (much of the caldera was filled with ash during the eruption itself as the ash column collapsed downwards). After 760,000 years, it is still plainly visible in satellite imagery and topographic maps (below).

After the eruptions ceased, water started to fill the caldera, eventually forming a 1,000 foot deep lake. The lake ultimately breached the margin of the caldera and rapidly carved a gorge hundreds of feet deep across the western edge of the Tableland. The walls of the Owens River Gorge expose a fine cross-section of the rhyolite tuff, allowing geologists to work out the sequence of events during the eruption.

Map courtesy of GeoMapApp

The Tablelands provide a window into the tectonic environment of the region. By covering the slope like a thick blanket, the tuff provided a blank slate on which post-eruption faulting can be easily seen and analyzed. There are dozens of faults, mostly trending north or northwest, with scarps that face west (the sunlit terraces) and east (the shadows). Geoblogger Callan Bentley provided a marvelous grounds-eye view of these faults in this post on his old NOVA Geoblog (Callan is now blogging primarily at Mountain Beltway under the auspices of the American Geophysical Union; he's always posting something interesting).

There is a much more extensive example of the broken nature of this landscape. The prominent mountain range on the upper right of the picture below is the White Mountains. In any other setting this mountain range would be a national park, but lying east of the Sierra Nevada, it sort of loses out. It tops out at 14,242 feet, rising as much as two miles above the adjacent Owens Valley. It is a gigantic fault block that formed when the land that is now the Basin and Range province began stretching and collapsing, forming a series of horsts (mountain blocks) and grabens (faulted valleys). The mountains lie in the rain shadow of the Sierra and never formed glaciers of any great extent. The highest arid slopes play host to the most ancient life on planet Earth: the Bristlecone Pines. The oldest Bristlecone is 5,062 years old. The Whites are a fascinating (and lonely) place to visit.

The Airliner Chronicles is one of my on-again/off-again serial features, which is usually updated whenever I fly somewhere.

Columns on Columns: Other Jointing Stories This Week

The vertical columnar joints that I saw at Devils Postpile weren't the only columns we saw on the field trip last week. We paid a visit to the Owens River Gorge on the Volcanic Tableland north of Bishop, California. The vast mesa is a rhyolite plateau that preserves a record of the one of the greatest explosions ever to shake North America, the eruption of the Long Valley Caldera. The 125 cubic miles of ash that was blasted into the sky 730,000 years ago produced the Bishop Tuff, which has been found across the western United States and as far east as Nebraska and Kansas. The giant explosion vacated a massive magma chamber, which subsequently collapsed, producing a hole two miles deep, ten miles wide, and 20 miles across. The caldera was partly filled with ash, but over the years a huge lake accumulated. When it finally spilled over the edge of the caldera, the new Owens River rapidly carved the gorge 400 feet deep. Along the way, the river exposed the columnar joints that developed as the hot ash settled, partly remelted, then cooled and contracted. They are easily accessed from one of the power station roads maintained by the Los Angeles Department of Water and Power.

As I was writing about the columnar jointing at Devils Postpile National Monument, it occurred to me that I had seen a number of geoblogosphere posts that involved the phenomenon in the last couple of days. Do posts by five bloggers make it columnar jointing week?

The youngest geoblogger, Sam at Geology Blues, has a note on Devils Tower.

Looking for Detachment's Silver Fox posted some beautiful pictures of Deep Creek Falls in Oregon, which thunder over some basalt columns. Then there were her pictures of jointing in basalt in the same general region, a Friday Mystery Photo.

Last Thursday it was Philip at Geology Blues with a picture of columnar joints in basalts on his commute in Oregon.

Though columnar joints aren't specifically mentioned, Glacial Till has pictures of the Columbia River Gorge and some of the basalt columns appear in the cliffs. Till writes of a new appreciation of the geology there.