The Redlands Earthquake Swarm: California Has Her Faults; Lots of Them!

A swarm of small and moderate earthquakes has been shaking things up in Southern California in and around the town of Redlands. The largest, on February 13, was magnitude 4.1, with five additional events between 3.1 and 3.6 in the days that followed. Well over a hundred smaller quakes have been detected as well. Swarms are interesting and exciting if you live on top of them, but they don't usually signify bigger things; the earth is shifting a bit, and that is often the end of it. On much rarer occasions, they may be a sign of an impending larger event, a foreshadowing disturbance of the earth similar to the cracks and pops a tree branch makes before it breaks (disclaimer: I am NOT making ANY kind of prediction; I don't have any access to data, nor do I have the background to do so, and seismologists know better than to try and make a short-term prediction of any quake). My message for the day is to remind people who live in earthquake country that they should ALWAYS be prepared for a large seismic event.

The view from Santa Rosa Peak in the Peninsular Ranges reveals the parallel valleys of the San Jacinto fault. The perspective is towards the west; the San Andreas fault is some twenty miles to the east of the peak

There is another opportunity here: a lot of people, when they hear of quakes in California, think San Andreas Fault. Many California residents who have lived here all their lives cannot think of the name of another fault in the state, but our landscape is literally crisscrossed by active faults (look at the map above; most of the brown lines are active faults). Most earthquakes in CA happen on faults other than the San Andreas, and this week's swarm is no exception. It appears to be taking place on one what is arguably the most active fault in the state, the San Jacinto fault.

The San Jacinto fault is certainly part of the San Andreas system. It splits off from the San Andreas at the east end of the San Gabriel Mountains, and runs roughly parallel to the San Andreas for 140 miles south into the Imperial Valley. It has the same type of motion, right lateral (features on the opposite side of the fault have been shifted to the observer's right). Since it began moving a few million years ago, something like 15 miles of lateral motion has taken place.

The San Andreas fault is justly famous for several devastating earthquakes, including the 1906 San Francisco event that killed 3,000 people, and the 1989 Loma Prieta quake (the World Series quake). It also produced a magnitude 8 event in southern California in 1857. But most of the time the fault is quiet (in a menacing way; it is storing up stress). Compare this with the history of the San Jacinto system (courtesy of Wikipedia):

1890 - Magnitude 6.5 that occurred in the "San Jacinto or Elsinore Fault region".

1892 - Another magnitude 6.5 occurred in the same region as the 1890 earthquake.

1899 San Jacinto Earthquake - Magnitude 6.4 earthquake destroys San Jacinto and Hemet.

1918 San Jacinto Earthquake - Magnitude 6.9 earthquake strikes the same area that was damaged by an earthquake 19 years earlier, with an epicenter roughly 10 mi NW of the previous earthquake.

1923 North San Jacinto Fault Earthquake - Magnitude 6.3 earthquake damaged the San Bernardino and Redlands area. Last time the fault, which runs under the I-215/I-10 interchange, ruptured in this area.

1937 Terwilliger Valley Earthquake - Magnitude 6.0

1942 Fish Creek Mountains Earthquake - Magnitude 6.3

1954 Arroyo Salada Earthquake - Magnitude 6.2

1968 Borrego Mountain Earthquake - Magnitude 6.5

1987 Superstition Hills Earthquake - Magnitude 6.6 (Note: some consider it to have occurred on a fault completely unrelated to the San Jacinto Fault Zone)

These quakes are considerably smaller than the 1906 event, by a factor of 32 or more (it takes the energy of 32 magnitude six quakes to equal the energy of a single magnitude 7 quake; a magnitude 8 quake is 32 times more powerful than a magnitude 7 quake and more than a thousand times more powerful than a six). But they clearly happen more often . The message is clear: to live in California, we must be prepared not just for the BIG, HUGE ONE, but also lots of lesser BIG ONES.

Another Whisper from the Past...and Another Catastrophe

I am always kind of haunted (in a good way) by ancient petroglyphs and pictographs. Most of my teaching in a classroom involves delivering information using one kind of rock (chalk) to form images on another kind of rock (slate, or an artificial derivative of slate). My images are far more transitory (they last right up to the moment the custodian erases them), but I feel an affinity for those who left images in stone hundreds or thousands of years ago. They were telling a story, sometimes with an obvious message (bighorn sheep here!), and sometimes with symbolism and codes that are long lost to history.

I'm back from our field studies journey in Death Valley, but I'm still finding a bit of material to post. We were out on the last day, making our way south out of the valley over Emigrant Pass and Wildrose Canyon. In a drier year we would have paid a visit to Aguereberry Point or the Wildrose Charcoal Kilns but snow and ice prevented us from doing so. With the additional time we paid a visit to some striking petroglyphs on a rhyolite ash flow of the Nova Formation. They depict animals, as seen above, and quite a few indecipherable symbols. Although one should NEVER touch the rock art, nor should one do rubbings, it is certainly a temptation! I wanted to reach up and touch this surface that was another's message. It's a moment of communicating with a fellow human being across the centuries (don't worry, neither I nor any of my students were touching the petroglyphs!).

While looking at the rock art, I took a step back and looked at the canvas the artist had chosen: an outcrop of tan colored rhyolite ash perhaps 30 feet thick. It lies interbedded with the conglomerates of the Nova Formation, which formed in a series of chaotic basins that developed over an extending terrane in the Panamint Mountains between 5.4 and 3.1 million years ago (the Emigrant Detachment). The rhyolite ash was formed in a violent explosion that inundated the region with the white powdery material. I looked closer at the rock and was struck by the absolute starkness of the basal contact. I was looking at a single moment in time, a matter of a few seconds from a momentous event several million years ago. It was a castastrophe.

By catastrophe, I don't mean a worldwide conflagration that eliminated whole species across the the planet. It was more local, perhaps affecting only a few hundred or few thousand square miles, but any living thing living within the region of the eruption was instantaneously buried in hot ash. Look at a close-up of the contact below...

This was an alluvial fan surface. A rugged mountain close by was shedding debris via streams, floods and mudflows, leaving a rocky landscape. It could have been a sunny day, maybe cloudy. Vegetation was growing among the rocks, and a variety of large animals were grazing nearby: numerous species of horses and camels, antelopes, mastodons, and the carnivorous animals, ancestors to today's canids and felines. There was a vast rumbling, a huge explosion ripped into the sky, and darkness quickly engulfed the area. Animals surely tried to escape, but there was nowhere to go. They were buried. Their last moment is memorialized by a thin line in a cliff that divides a conglomerate from a white ash layer.

I'd Like To Speak to your Site Engineer, and uh, Why Are You Strip Mining Our National Park?

Who in the world chose this particular slope to build the offices and dormitories for the mine complex near by? Maybe the perspective makes it look steeper and more dangerous than it actually is, but every single piece of rock on that slope came down quite rapidly from the cliffs above. Maybe someone familiar with the site can explain to me how those buildings aren't deathtraps.

The first Europeans to fully experience the delights of the Death Valley region were the Forty-Niners who got marooned on the valley floor for several weeks after running out of supplies. They gave the valley its name, even though only one of the travelers actually died. But the real pioneers were the miners who soon followed. A lot of dreams of avarice and riches died in the vicious desert environment, and few of the mines ever actually paid dividends to their owners.

A big exception was the mining of borate minerals, used in soap-making, glass-making and a wide variety of other industrial uses. Borates were a rare resource in the world prior to the 1870's. They were discovered in California during the 1860's in the Clear Lake area, but it wasn't until large deposits were found in the Death Valley region in the 1880's that serious mining took place, despite the extreme isolation. The nearest railroad depot was near Barstow, more than a hundred miles away. The mining companies designed the twenty-mule team wagons to transport the ores, and the wagons became an enduring symbol of the company even into the present day.

The mines were active until borate minerals were found in the Calico Mountains near Barstow, right next to the railroad depot. The Death Valley mines were immediately idled. A failed agricultural well near the present-day town of Boron in 1927 revealed the presence of a vast body of borate minerals underneath the desert floor, and a giant open pit mine was quarried. It continues to provide much of the world's supply of borates, despite an ongoing bitter strike.

Old mines, with their headframes, tailing piles and associated ghost towns, are a colorful part of the history and heritage of the Death Valley region. Which makes the scene below all the more jarring. It is a modern open pit mine along the road to Dante's View above Zabriskie Point. Even though the region was made a national monument in 1933 (and a national park in 1994), prior existing claims were honored and mining continued on a small scale. The initiation of highly visible open-pit mining operations in the 1970's elicited storms of protest, and Congress changed the laws controlling mining in the parks in 1976. The underground operations of the Billie Mine at Ryan (seen in the picture above) ended in 2005, so at this time no mining is taking place in Death Valley National Park. The Park Service has some excellent sites describing the history of mining in Death Valley here and here.


What isn't clear to me is whether the tailings from the 1970's operations will ever be cleaned up.

A Global Warming Bucket List...

I am writing this blog post today in penance for my faux pas the other day in describing the "climate" at Death Valley as "unusually wet" this week. It was the weather that was wet, not the climate. It was a sophomoric mistake, made worse in my mind because of the cacophony of idiots who decided that global warming and climate change are myths because it snowed in Washington D.C. last week. Changes due to global warming are happening all around us. To deny it, like many conservative politicians and talking heads are doing, is comparable to saying the Titanic isn't sinking as the water laps around one's ankles.

Over at High Country News, "Writer on the Range" Tim Lydon offers up a bucket list of those places to see, not before we die, but before they disappear due to the effects of global warming and climate change. He concentrated on Alaska, ground zero for the effects of warming climate, and areas like Yellowstone and Glacier National Parks in the lower 48 states. It brought to mind some places I need to see soon.

Lydon notes the glaciers in Glacier National Park may disappear in as little as a decade, but California has her glaciers too, including the Palisades Glaciers, seen above in a view from the White Mountains across the Owens Valley. The glaciers of the Sierra have lost something like 75% of their volume over the last century. They won't be around long, and I've only hiked up to one of them.

Another part of our heritage that may disappear is the relic forests of the Mojave. During the ice ages, forests of conifers extended across the Mojave Desert and Basin and Range Provinces. Adapted to wetter conditions, the species retreated as the region became a desert, and most of the forests disappeared until a few small islands remained. These include small white fir forests at the summit of Kingston Peak and the Clark Range. I've never seen them up close.

The Joshua Trees are losing ground as well. They will probably be present for many centuries after I am gone, but their range is decreasing as the climate warms. Their seeds used to be spread in the dung of ground sloths, but without the sloths which went extinct 11,000 years ago, they can't propagate to higher cooler mountain ranges as effectively as conditions continue to warm up.
I've watched with dismay as the forests of my youthful adventures in Southern California have burned up in massive wildfires. The giant 270 square mile fire in Angeles National Forest last year hit me especially hard. Wildfires have always been a fact of life in SoCal. Whether the increasing intensity and extent of the wildfires results from warming or from management issues, the forests will probably be replaced with species characteristic of a drier environment. My favorite Jeffrey Pine forests on Mt. Baldy and in Holcomb Valley may become a thing of the past.

What's changing in your region?

Death Valley Winter Olympics: Coyotes 6, Fifi 0

Not a particularly geologic entry tonight, but I have never had the chance to photograph a coyote from a reasonably close distance. The morning patrol at Stovepipe Wells Campground was in full swing today, and Wily E. Coyote was cooperating with yours truly. It could have been the breakfast burrito I was chomping on, but I wasn't sharing.

If you visit a place like Death Valley, and feel a need to bring along Fifi and Princess, you are allowed to. If you wonder why they are supposed to stay on leashes, here is your answer. When the coyote appeared on the scene, I noticed that two little Yorkies were leashed to the bench in front of the store. Wily E. noticed too, and was coming over to investigate. The owner dropped his purchases and gathered up his little treasures in a hurry!

Coyotes are an American original. They evolved here, and have been found as fossils across the North American continent and especially in California, at the La Brea tar pits and numerous other localities. They are one of the few predators that has expanded its range, despite the efforts of humans to eradicate them in many places. The ones I've seen in Death Valley have looked pretty healthy (in part, no doubt, to the folks that left their pet food...and, uh, their pets outside at night).

I enjoyed their night-time serenades!

The Last Animal Anyone Expects to Find: The Rarest Creature in Death Valley

Looking over the blasted barren rocks of Death Valley National Park, one is struck by the apparent lack of life. A region that averages less than two inches of rain in a year, with summer temperatures regularly topping 120 degrees, is just not going to have a lot of moisture left over to support life. and yet life persists, and sometimes in incredible ways. Hundreds of species are found in the region, including dozens of endemic and endangered species.

What is the last kind of animal you would ever expect to find in a place like Death Valley? Here's a candidate: in an outlying part of the park, just over the border in the state of Nevada, there is a barren hillside of carbonate rock (limestone), that has been twisted upwards and fractured. Strolling towards the base of the hill, one notices a cavern opening surrounded by reinforced fencing. It's a deep cave, more than 900 feet, but surprisingly, it is filled with groundwater at a constant temperature of 92 degrees.

Looking through the fence, one can see the small pool of water at the bottom of the narrow cleft. The monitoring equipment is a clue that something extraordinary lives here. It's a fish! And not just any fish, it is probably the rarest fish in the world, the Devil's Hole Pupfish. The species has lived in this little bit of water for the last 20,000 years, when it was isolated here by the drying of the glacial meltwater lakes that punctuated the Death Valley region. Through droughts, climate change, cooling, and in the last few years, interference by human beings, the little community of a few hundred individuals has grown, reproduced and died in this opening.

A few decades ago, as many as 600 fish lived here, but by 2004 the population had crashed to just over two dozen individuals. The population had recovered by 2007 to 126 fish, but their continued existence will always be tenuous. They would have been extinct in the late 1970's had the Supreme Court of the United States not stepped in. It was an early major test of the Endangered Species Act. As can be seen below, major efforts have been expended to monitor the health of the population.

It is not really possible to see the individual fish at Devils Hole, but a much larger and more stable population of a related species can be seen a few short miles away at Ash Meadows. The pool below is Crystal Spring, which produces 2,600 gallons per minute of 87 degree water. The Ash Meadows Pupfish lives in the pond and nearby stream, and is far easier to see, as we did today.

My picture of the Ash Meadows fish didn't come out, so I am slipping a picture of the Salt Creek pupfish from a previous trip. The Salt Creek fish live in the bottom of Death Valley not too far from Furnace Creek Resort.
Four species of pupfish live in various parts of Death Valley, with some living in the hottest and saltiest water of any fish species on the planet. Others live in fresh water. They are all descended from a single species of pupfish that lived in the glacial meltwater lakes of the ice ages. An example of real resilience in the face of difficult conditions!

Death Valley Not Quite So Dry This Year...

Blogging from the road! There is actually some web access in Death Valley...slow, sensitive, moody, but it works, sort of. I'm out here with nearly three dozen students and volunteers, experiencing an unusually wet climate (correction: "weather", see the comments) by Death Valley standards. They've received a year's worth of precipitation (~2 inches!) in about three week's time. Most of the dirt roads are out of commission, and some of the paved roads are still impassable as well (Artist's Drive and Dante's View). Still, we have found plenty to do.

There are certainly some unusual sights for Death Valley: morning dew soaking our camp in the morning, a bit of fog in the early morning, but best of all: a flowing river and a huge lake!

The Amargosa River drains a huge region of western Nevada, but is generally dry most of the time except along a few precious stretches where ground water is forced to the surface. This year it is raging torrent (ok, a babbling brook) all across the bottom of the Death Valley graben. One could almost float an inner tube in it.

The lake covers a fair portion of the ~100 square mile saltpan. Although it is large, it probably is no more than a foot or so deep, and will undoubtedly dry up in coming months as the weather warms up. It provides a beautiful foreground for viewing the snow-capped peaks of the Panamint Mountains.