2010 August 22 Sunday
SoCal Seen Due For Big Earthquake

The next SoCal earthquake is probably stuck somewhere in a traffic jam.

Earthquakes have rocked the powerful San Andreas fault that splits California far more often than previously thought, according to UC Irvine and Arizona State University researchers who have charted temblors there stretching back 700 years.

The findings, to be published in the Sept. 1 issue of Geology, conclude that large ruptures have occurred on the Carrizo Plain portion of the fault – about 100 miles northwest of Los Angeles – as often as every 45 to 144 years. But the last big quake was in 1857, more than 150 years ago.

You can see the fault running thru the Carrizo Plain in a USGS map. It is toward the southern end of the San Joaquin valley. That seems a much bigger problem for Bakersfield than for California coastal cities.

Likely soon.

UCI researchers said that while it’s possible the fault is experiencing a natural lull, they think it’s more likely a major quake could happen soon.

“If you’re waiting for somebody to tell you when we’re close to the next San Andreas earthquake, just look at the data,” said UCI seismologist Lisa Grant Ludwig, principal investigator on the study.

If an 8.0 earthquake lets loose then anyone have a good idea on the size of the impact 75-100 miles away given California geology? Big quakes like the New Madrid 1812 that occur in less rocky soil can propagate much further. That one rung church bells in Boston. But the US West Coast doesn't have the geology needed for major damage over hundreds of miles. Still, what's the realistic diameter of the major damage area?

By Randall Parker    2010 August 22 02:17 PM   Entry Permalink | Comments (1)
2010 June 19 Saturday
40 Million Years Ago North America Volcanic Eruptions

North American volcanic eruptions of 40 million years ago spewed climate-cooling sulfur aerosols on a scale not seen in modern times.

Millions of years ago, volcanic eruptions in North America were more explosive and may have significantly affected the environment and the global climate. So scientists report in this week's issue of the journal Nature.

The researchers found the remains--deposited in layers of rocks--of eruptions of volcanoes located on North America's northern high plains that spewed massive amounts of sulfate aerosols into the atmosphere 40 million years ago. The scientists conducted their research at Scotts Bluff National Monument, Neb., and in surrounding areas.

"Combining measurements of the sulfate in ancient volcanic ash beds with a detailed atmospheric chemistry model, we found that the long-ago chemistry of volcanic sulfate gases is distinct from that of more modern times," says Huiming Bao, a geologist at Louisiana State University and lead author of the paper.

"This is the first example showing that the history of massive volcanic sulfate emissions, and their associated atmospheric conditions in the geologic past, may be retrieved from rock records."

The fact that the high sulfate emissions happened 40 million years ago doesn't demonstrate the final end of a geological era. This can happen again. About every 650,00 years or so the Yellowstone area erupts. The last eruption was 640,000 years ago and was 20 times as large as the 1815 Tambora eruption discussed below. This cycle of eruption might not be over yet.

A similar volcanic event to the long-ago past likely will happen again, Bao says: in the next Yellowstone eruption.

If we are lucky the next eruption large enough to prevent summers won't happen until we have enough technology (e.g. nanobots, fusion reactors) to enable us to easily deal with the consequences.

For almost the last couple of centuries have been sufficiently uneventful in terms of volcanic eruptions. So it might seem that nature isn't likely to send something at us that we can't easily handle. But go back just a little further and a different picture emerges.

The closest analog, Bao believes, is the 1783 Laki, Iceland, eruption and the subsequent "dry fogs" in continental Europe.

That event devastated Iceland's cattle population. People with lung problems suffered the worst, he says.

In North America, the very next year's winter, that of 1784, was the longest and one of the coldest on record. The Mississippi River froze as far south as New Orleans. The French Revolution in 1789 may have been triggered by the poverty and famine caused by the eruption, scientists believe.

Climate cooling from volcanoes on the scale of the1783 Laki, Iceland, eruption is not that rare. 1816 is know as the "Year Without Summer" due to the April 10, 1815 Tambora eruption, which was the biggest volcanic eruption in the last 200 years. It caused cold weather for 2 years and widespread hunger. The 1600 Huaynaputina Peru eruption was smaller than Tambora (volcanic explosivity index (VEI) of 6 versus 7 for Tambora). Yet it spewed as much sulfur as some VEI 7 eruptions and caused famine in Russia.

A VEI eruption like Tambora would cause famine in poorer countries. A VEI 8 eruption would cause famine even in some developed countries. A VEI 8 eruption in a developed country would kill millions near the eruption and, depending on where it happens, even kill tens of millions in that country.

By Randall Parker    2010 June 19 06:34 PM   Entry Permalink | Comments (14)
2010 May 24 Monday
Earthquake Risk Calculated For US Northwest

Move over California. Oregon, Washington state, and British Columbia might have a far more devastating earthquake.

CORVALLIS, Ore. – The major earthquakes that devastated Chile earlier this year and which triggered the catastrophic Indonesian tsunami of 2004 are more than just a distinct possibility to strike the Pacific Northwest coast of the United States, scientists say.

There is more than a one-in-three chance that it will happen within the next 50 years.

New analyses by Oregon State University marine geologist Chris Goldfinger and his colleagues have provided fresh insights into the Northwest’s turbulent seismic history – where magnitude 8.2 (or higher) earthquakes have occurred 41 times during the past 10,000 years. Those earthquakes were thought to generally occur every 500 years, but as scientists delve more deeply into the offshore sediments and other evidence, they have discovered a great deal more complexity to the Cascadia Subduction Zone.

Lots of disasters are just waiting to happen. Earthquakes, large volcanic eruptions, asteroid strikes, and even another Carrington Event could cause massive disruptions. Earthquakes are the least of the 4 listed disasters in terms of potential for lives lost and disruption.

Watch out for a mega-quake.

Based on historical averages, Goldfinger says the southern end of the fault – from about Newport, Ore., to northern California – has a 37 percent chance of producing a major earthquake in the next 50 years. The odds that a mega-quake will hit the northern segment, from Seaside, Ore., to Vancouver Island in British Columbia, are more like 10 to 15 percent.

A magnitude 9 earthquake would tear highways to pieces. Imagine trying to bring in help afterward. Rail lines and highways would be impassable. My guess is the rail lines could be restored to working order much faster.

The OSU professor is convinced that the Pacific Northwest is at risk for an earthquake that could meet – or exceed – the power of seismic events that took place in Chile, as well as Haiti. If a magnitude-9 earthquake does strike Cascadia, he says, the ground could shake for several minutes. Highways could be torn to pieces, bridges may collapse, and buildings would be damaged or even crumble. If the epicenter is just offshore, coastal residents could have as little as 15 minutes of warning before a tsunami could strike.

Anyone who lives in the northwest made any special preparations for an earthquake? Ready to survive for weeks without electric power or city water?

By Randall Parker    2010 May 24 10:34 PM   Entry Permalink | Comments (17)
2009 November 23 Monday
Toba Supervolcano Deforested India 73,000 Years Ago

About 73,000 years ago (74,000 by some estimates) a massive volcano on the Indonesia island of Sumatra erupted with a volcanic explosivity index (VEI) of 8. Such an eruption is so severe in its effects it basically would cause the deaths of billions of people today. New evidence finds that Toba's eruption caused deforestation in what is now central India.

CHAMPAIGN, Ill. — A new study provides "incontrovertible evidence" that the volcanic super-eruption of Toba on the island of Sumatra about 73,000 years ago deforested much of central India, some 3,000 miles from the epicenter, researchers report.

The 800 cubic kilometers of ash ejected by Toba compares with the mere 160 cubic kilometers ejected by the 1815 Tambora eruption. The larger Toba eruption caused an ice age that lasted 1,800 years.

The volcano ejected an estimated 800 cubic kilometers of ash into the atmosphere, leaving a crater (now the world's largest volcanic lake) that is 100 kilometers long and 35 kilometers wide. Ash from the event has been found in India, the Indian Ocean, the Bay of Bengal and the South China Sea.

The bright ash reflected sunlight off the landscape, and volcanic sulfur aerosols impeded solar radiation for six years, initiating an "Instant Ice Age" that – according to evidence in ice cores taken in Greenland – lasted about 1,800 years.

During this instant ice age, temperatures dropped by as much as 16 degrees centigrade (28 degrees Fahrenheit), said University of Illinois anthropology professor Stanley Ambrose, a principal investigator on the new study with professor Martin A.J. Williams, of the University of Adelaide. Williams, who discovered a layer of Toba ash in central India in 1980, led the research.

We are not prepared for such an event today. Even 5 or 10 years to prepare could at most save a small fraction of the human race.

The 1815 Tambora VEI 7 eruption caused crop failures for 2 years. Imagine that happening today with nearly 7 billion humans using a much larger fraction of total planetary biomass. If a VEI 7 eruption could somehow be predicted several years in advance then industrialized nations could stockpile enough food to make it thru the crop failures. But poorer nations would face starvation on a scale not seen in the last 100 years.

Since geologists can't predict VEI 7 and up eruptions years in advance I do not expect we'll possess the ability to handle such an eruption until nanotechnology enables such huge increases in living standards that it becomes possible to very cheaply produce huge amounts of excess food and very cheap ways to store it for years.

By Randall Parker    2009 November 23 08:58 PM   Entry Permalink | Comments (9)
2009 September 30 Wednesday
Distant Earthquakes Weaken San Andreas Fault

Live near a major fault? When you read about distant earthquakes brace for the possibility of big local one as a result.

HOUSTON -- (Sept. 30, 2009) -- U.S. seismologists have found evidence that the massive 2004 earthquake that triggered killer tsunamis throughout the Indian Ocean weakened at least a portion of California's famed San Andreas Fault. The results, which appear this week in the journal Nature, suggest that the Earth's largest earthquakes can weaken fault zones worldwide and may trigger periods of increased global seismic activity.

"An unusually high number of magnitude 8 earthquakes occurred worldwide in 2005 and 2006," said study co-author Fenglin Niu, associate professor of Earth science at Rice University. "There has been speculation that these were somehow triggered by the Sumatran-Andaman earthquake that occurred on Dec. 26, 2004, but this is the first direct evidence that the quake could change fault strength of a fault remotely."

Live in an earthquake zone? I do. Want to be prepared? Look at the building you live in and the building you work in and ask yourself whether you are likely to die in either structure in event of an earthquake. If so, change jobs or move as appropriate. A really big quake in SoCal will take out water supplies in some areas. Think about putting in some big water storage bottles (appropriately padded and braced to prevent breakage) so you can keep drinking water after the Big One.

Last night I was watching a History Channel show about the odds of a really big earthquake in Southern California. One of the people on the show said the scientific consensus is for a 99% probability in the next 30 years. If you live in SoCal you really ought to prepare for it.

By Randall Parker    2009 September 30 10:30 PM   Entry Permalink | Comments (3)
2009 June 14 Sunday
Mount St Helens Supervolcano Potential?

Maybe Mt. St. Helens connects to a common hot zone that it shares with Mt. Rainier and Mt. Adams.

Graham Hill of GNS Science, an earth and nuclear science institute in Wellington, New Zealand, led a team that set up magnetotelluric sensors around Mount St Helens in Washington state, which erupted with force in 1980. The measurements revealed a column of conductive material that extends downward from the volcano. About 15 kilometres below the surface, the relatively narrow column appears to connect to a much bigger zone of conductive material.

Keep in mind this may come to nothing. But a massive volcanic eruption will happen sooner or later. The Mount Tambora eruption in 1815 and the Krakatoa event of 1887 were disruptive of global climate. Add in the solar Carrington event of 1859 and natural disruptions were far more frequent and drastic in the 19th century than anything we've seen since. Are we overdue?

The world's population is far larger than it was when eruptions in the 19th century caused massive crop failures. A larger fraction of the population today lives off of crops rather than hunting and gathering. They have less potential to fall back on hunting and gathering. I also worry large scale crop failures will cause people to hunt endangered species more heavily. A big enough eruption could therefore cause species extinctions.

By Randall Parker    2009 June 14 09:21 PM   Entry Permalink | Comments (2)
2009 April 09 Thursday
April 10 In History: Tambora Eruption 1815

A Wired article reminds that April 10 is the day in 1815 when the Tambora volcano erupted with full force (Volcanic Explosivity Index of VEI of 7), bringing a cold and hungry summer.

Snow fell in New England and Eastern Canada in June. (Quebec City got a foot of the stuff.) Frost was recorded in each of the summer months. Drought struck in July and August, and the sunlight was weak. Crops were stunted or failed entirely. Much of what survived and looked near to harvest was killed off by a September frost.

1816 weather was even worse than 1815, with widespread starvation as a result. Tambora was a bigger eruption than the better known 1887 Krakatoa eruption (a mere VEI 6).

The eruption even caused bad wine. But I bet the beer was still pretty good. So not to worry.

Even the wine from 1816 was bad.

Alain Vauthier, who owns one of the oldest vineyards in Bordeaux, France, keeps a fair bit of wine from each vintage in the cellar. He has an impressive collection, which stretches back to the beginning of the 19th century, but there are only a few bottles from 1816. Vauthier says that's as it should be.

"It is not a good vintage," Vauthier says. "It is a bad time, bad weather, bad summer."

Daniel Lawton is the owner of Bordeaux's oldest wine brokerage house. His assessment of the 1816 vintage is even less charitable.

"Detestable, you understand? Horrible," Lawton says. "A quarter of the normal crop. Very difficult to make good wine. Just a terrible year."

A map of volcanic eruptions in Indonesia since 1900 AD shows that Indonesia is an excellent candidate for the next huge volcanic eruption.

The Santorini (or Thera) eruption of about 1630 BC (the date is not precise) was close in size to Tambora. That eruption wiped out Bronze Age Minoans on a Greek (er, Minoan) island. But the biggest eruption in the last 2 million years was again in the Indonesian island chain: Toba about 74000 years ago

The scale of the Toba eruption is difficult to comprehend. Pyroclastic flows (hot flows of ash and pumice) covered an area of at least 20,000 square kilometers (7,700 sq mi), with deposits as thick as 600 m (2,000 ft) near the vents.

Ash fall was widespread over much of southeast Asia. An ash layer approximately 15 cm (6 in) thick was deposited over the entire Indian subcontinent. Our appreciation of the magnitude of this eruption continues to grow as Toba ash is recognized farther and farther from the source.

The volume of the Toba eruption is estimated at 2,800 cubic kilometers (670 cu mi). To give some comparison with more recent eruptions, the 1980 eruption of Mount St. Helens produced less than 1 cubic kilometer (0.25 cu mi). Vesuvius (A.D. 79) erupted about 5 cubic kilometers (1.2 cu mi), and Krakatoa in Indonesia (1883) about 12 cubic kilometers (3 cu mi). Closer to home, the volume of Kilauea's ongoing eruption is about 2.6 cubic kilometers (0.6 cu mi), erupted over the last 22 years.

VEI isn't the only thing to worry about with volcanoes. Just how much of the ejecta is sulfur makes a really big difference with the weather. The 1600 Huaynaputina eruption in Peru was only a VEI 6 but it released so much cooling sulfur aerosols that it caused crop failures with famine in Russia and other crop failures.

Other volcanic eruptions of approximately Huaynaputina’s size or larger have occurred more recently, including Pinatubo in 1991 and Indonesia’s Krakatau in 1883, but they didn’t cool Earth as much and didn’t trigger societal upheavals. The reason, researchers say, may stem from the immense volumes of sulfur-rich fluids that fueled Huaynaputina’s eruption, which released an exceptional amount of planet-cooling aerosols.

So picture a VEI 7 eruption total with high sulfur aerosol content. Then picture a huge increase in food prices and lots of cold weather for a couple of years. Or picture a VEI 8 eruption if you really want to think grim thoughts. Hopefully this won't happen before the Singularity.

By Randall Parker    2009 April 09 05:59 PM   Entry Permalink | Comments (14)
2009 January 25 Sunday
SoCal Overdue For Carrizo Plain Earthquake

Sooner or later southern California will get hit by a massive damaging earthquake. It will not only kill people in the initial event but also so damage infrastructure that electric power, natural gas, water, and other basic utilities will be knocked out for extended lengths of time. Water will be disrupted for weeks to months in some areas with other utility disruptions as well. The vast majority of SoCal residents will survive the big one. But then migrations will occur away from places that lose the ability to support high density populations. With all this in mind new research shows that a section of the San Andreas fault in San Luis Obispo County goes off at about 137 year intervals and it is overdue for another big one.

The Carrizo Plain section of the San Andreas has not seen a massive quake since the much-researched Fort Tejon temblor of 1857, which at an estimated magnitude of 7.9 is considered the most powerful earthquake to hit Southern California in modern times.

But the new research by UC Irvine scientists, to be published next week, found that major quakes occurred there roughly every 137 years over the last 700 years. Until now, scientists believed big quakes occurred along the fault roughly every 200 years.

We were due for another quake in that area starting around 1994. This discovery is made possible by advances in dating methods.

They went back to her archive, and the redating effort, led by scholar Sinan Akciz, found that the four big earthquakes before the 1857 temblor probably occurred around 1310, 1393, 1585 and 1640.

The Carrizo Plain is near the southern end of the San Joaquin valley about 100 miles from Los Angeles. As you can see from this map the towns of California Valley, Simmler, McKittrick, Taft, Maricopa, and New Cuyama will be especially hard hit next time this fault rips.

I hear Jerry Lee Lewis singing "Whole Lot Of Shaking Going On".

On January 9, 1857 at 8:20 am, an earthquake with a estimated magnitude of 8.0 occurred just north of Carrizo Plain. This quake caused nearly 30 feet (9 m) of lateral offset within Carrizo Plain, and ruptured the surface along the trace of the fault for about 220 miles (350 km). It was one of the greatest earthquakes ever recorded in the United States. Buildings in Los Angeles were severely shaken, and the quake was felt from felt from Marysville south to San Diego and east to Las Vegas, Nevada. The current of the Kern River was turned upstream, and water ran four feet deep over its banks. The waters of Tulare Lake were thrown upon its shores, stranding fish miles from the original lake bed. The waters of the Mokelumne River were thrown upon its banks, reportedly leaving the bed dry in places. The Los Angeles River was reportedly flung out of its bed, too.

I live even closer to this fault (maybe 70 miles) than the people of LA do. Bakersfield is even closer at about only 40 miles away. People in SoCal ought to read a good earthquake preparedness guide such as this preparedness guide by the LA Fire Department. Note that they say "Water is the most important item to store". Got 5 gallons stored per person in your residence? If not, you have a problem come the Big One.

Some of you out in the middle of the United States might be thinking "Oh, those crazy Californians, the dangers they choose to live with". Think again. The border of Arkansas, Missouri, Illinois, Kentucky, and Tennessee is one of the highest earthquake hazard risk zones. A repeat of the three magnitude 8 (yes, 3 of them!) 1811 and 1812 New Madrid earthquakes would devastate much of the surrounding region and cause damage in very distant places. The 1811 New Madrid quake rang church bells in Boston.

Earthquakes in the central or eastern United States affect much larger areas than earthquakes of similar magnitude in the western United States. For example, the San Francisco, California, earthquake of 1906 (magnitude 7.8) was felt 350 miles away in the middle of Nevada, whereas the New Madrid earthquake of December 1811 (magnitude 8.0) rang church bells in Boston, Massachusetts, 1,000 miles away. Differences in geology east and west of the Rocky Mountains cause this strong contrast.

By Randall Parker    2009 January 25 10:25 AM   Entry Permalink | Comments (2)
2008 July 19 Saturday
Underwater Volcanic Eruption Caused Mass Extinction?

One thing strikes me about the world's history of huge volcanic eruptions: Another one is probably inevitable. 93 million years ago a volcanic eruption might have caused a worldwide massive depletion of oceanic oxygen. All those fish that get oxygen from water would have died in massive numbers.

University of Alberta scientists contend they have the answer to mass extinction of animals and plants 93 million years ago. The answer, research has uncovered, has been found at the bottom of the sea floor where lava fountains erupted, altering the chemistry of the sea and possibly of the atmosphere.

Earth and Atmospheric Science researchers Steven Turgeon and Robert Creaser found specific isotope levels of the element osmium, an indicator of volcanism in seawater, in black shale—rocks containing high amounts of organic matter—drilled off the coast of South America and in the mountains of central Italy.

According to their research, the eruptions preceded the mass extinction by a geological blink of the eye. The event occurred within 23 thousand years and the underwater volcanic eruption had two consequences: first, nutrients were released, which allowed mass feeding and growth of plants and animals. When these organisms died, their decomposition and fall towards the sea floor caused further oxygen depletion, thereby compounding the effects of the volcanic eruption and release of clouds of carbon dioxide in to the oceans and atmosphere. The result was a global oceanic anoxic event, where the ocean is completely depleted of oxygen, Anoxic events—while extremely rare—occur in periods of very warm climate, which means that this research could not only help prove a mass-extinction theory, but also help scientists studying the effects of global warming.

If we manage to develop rejuvenation therapies and also to avoid extinction at the hands of robots and nano-goo then many of us will live to see massive volcanic eruptions. I'm thinking that perpetually youthful people who have thousands of years to prepare will want to build underground bunkers for the day when some big volcano on the scale of the Toba eruption (called VEI-8 events) finally goes off.

We won't get wiped out by an asteroid unless one comes in the next few decades. At some point in this century we should possess the technologies needed to detect and deflect any big asteroid. But volcanoes are much tougher. Will we ever possess technology needed to scale down the size of volcanic eruptions? Will we at least gain the capability to predict them in advance?

By Randall Parker    2008 July 19 12:32 AM   Entry Permalink | Comments (4)
2008 April 15 Tuesday
Big California Earthquake Within 30 Years

The next big earthquake in California might not come until after the singularity or the robot take-over. So we might not still be around to deal with it.

The odds of avoiding a major quake in the next 30 years are about the same as flipping a coin and having it come up heads six times straight: almost nil, according to a new study.

The study, released April 14 in simultaneous news conferences at USC and in the San Francisco Bay area, finds a greater than 99 percent chance that a quake as big or bigger than the 1994 Northridge will hit somewhere in California by 2037.

But it could happen a lot sooner, according to the study. The chance of a big quake within five years is 50-50. The 10-year probability is about 75 percent.

Odds of a 7.5 quake are almost 50:50.

The 30-year probability of an even more damaging, magnitude 7.5 quake – nearly 30 times stronger than Northridge – is almost 50 percent, USC University Professor Thomas Jordan said at the news conference.

Last night Santa Barbara was rattled by a 3.2 earthquake. It was just strong enough to make one wonder if a much bigger one was about to start. Luckily it was weak enough that internet access kept working. After a really big quake it might make sense to move out of state until communications and electric power get restored.

I am more worried about Peak Oil than I am about the next big earthquake. Declining oil production will cost us far more than an 8.0 earthquake even if that earthquake hits a major city.

By Randall Parker    2008 April 15 11:02 PM   Entry Permalink | Comments (12)
2007 April 29 Sunday
Creation Of North Atlantic Melted Ice Caps?

The creation of the North Atlantic Ocean might have spewed so much carbon dioxide that it toasted the Arctic ice covering.

Michael Storey at Roskilde University in Denmark and colleagues have found evidence that a huge volcanic eruption, 55 million years ago, unleashed so much greenhouse gas into the atmosphere that world temperatures rose by as much as 8°C – with the Arctic ocean reaching a toasty 25°C.

So then did polar bears evolve since then? Ditto for some of the other North American and Northern Russian cold weather animals?

Massive volcanic eruptions are a much bigger threat to humanity than asteroids. For the asteroid threat we could (if we were wiser) develop excellent systems for detecting and deflecting asteroids. But I doubt that we can do much to prevent massive eruptions (though if anyone has any ideas on that please post in the comments).

If geological scientists could predict a massive volcanic eruption on some part of the Earth I would take that prediction as an argument for a massive nuclear reactor construction project in other parts of the globe. In the early stages of eruption light from the sun would get blocked out. So solar panels would become worthless and the planet would become really cold. Later the planet might go through a big warming as Michael Storey thinks happened before. But first we'd need to survive the very cold and dark period. Nukes would help on that score.

The farther out a volcanic eruption prediction could be made the more we could do to reduce the loss of life. We could stockpile food and medicine, move people away from the eruption area, build cold weather shelters, and build nuclear power plants.

How big can a volcanic eruption get? Tambora in 1815 spewed 100 times as much as Mt. St. Helens in 1980 but Toba about 71,000 years ago spewed 2800 times as much as Mt. St. Helens. Toba's 2800 sq. km. spew is not the biggest in history. Note that the Yellowstone Caldera could become a supervolcano again and the current US territory has been the site of other supervolcanoes, including one that spewed up 5000 sq. km. of stuff.

Update: The scientists who conducted this research see it as evidence that a big spike in CO2 and methane can cause global warming.

The Paleocene-Eocene thermal maximum, or PETM, was a period of intense warming that lasted roughly 220,000 years. In addition to the warming of sea surface waters, this event – characterized by scientists as a "planetary emergency" – also greatly increased the acidification of the world’s oceans and led to the extinction of numerous deep-sea species.

Warming periods in Earth’s history are of interest as analogs to today’s climate change, Duncan said.

The international science team was able to link the PETM with the breakup of Greenland from northern Europe through analyzing the ash layers deposited toward the end of the peak of the volcanic eruptions. Using chemical fingerprints and identical ages, they were able to positively match ash layers in east Greenland with those in marine sediments in the Atlantic Ocean.

"We think the first volcanic eruptions began about 61 million years ago and then it took another 5 million years for the mantle to weaken, the continent to thin and the molten material to rise to the surface," Duncan said. "It was like lifting a lid. The plate came apart and gave birth to the North Atlantic Ocean."

If the human race doesn't get wiped out by robots, nanotech replicators, or an invading alien species then at some point we are going to need to do large scale climate engineering to compensate for future periods of intense volcanic activity.

By Randall Parker    2007 April 29 12:54 PM   Entry Permalink | Comments (10)
2006 June 25 Sunday
Southern California At High Earthquake Risk

With Hurricane Katrina people had a couple of days notice that something highly destructive was coming their way. When the big quake comes to SoCal and LA gets wrecked we'll find out about it right when the big ride starts. The last really big SoCal earthquake was in 1690. The San Andreas Fault has been building up unreleased tension for at least 300 years.

A researcher investigating several facets of the San Andreas Fault has produced a new depiction of the earthquake potential of the fault's southern, highly populated section. The new study shows that the fault has been stressed to a level sufficient for the next "big one"—an earthquake of magnitude seven or greater—and the risk of a large earthquake in this region may be increasing faster than researchers had believed, according to Yuri Fialko of Scripps Institution of Oceanography at the University of California, San Diego.

Historical records show that the San Andreas Fault experienced massive earthquakes in 1857 at its central section and in 1906 at its northern segment (the San Francisco earthquake). The southern section of the fault, however, has not seen a similar rupture in at least 300 years.

Although seismologists have not been able to predict when a great earthquake will occur on the southern San Andreas, most believe such an event is inevitable. Fialko has produced the clearest evidence to date of the strain buildup that will ultimately result in a large earthquake along the southern San Andreas Fault, a 100-mile segment that cuts through Palm Springs and a number of other cities in San Bernardino, Riverside and Imperial counties. Such an event would be felt throughout much of Southern California, including densly populated areas of metropolitan Los Angeles and San Diego.

If you are a SoCal resident now might be the time to start thinking about a really extended trip to some other part of the world.

"All these data suggest that the fault is ready for the next big earthquake but exactly when the triggering will happen and when the earthquake will occur we cannot tell. It could be tomorrow or it could be 10 years or more from now," said Fialko.

Bonds have maturities measured in decades. Earthquakes are a substantial risk factor. Hey there bond investors, you might want to think twice before buying bonds of SoCal governments.

Fialko found evidence that the southern San Andreas is mostly locked and continues to accumulate significant amounts of strain. He calculated the rate at which the fault is moving and estimated the "fault slip rate," the pace of the plate movement at the fault, at about an inch per year. According to Fialko, this means that during the last 300 dormant years the fault has accumulated approximately six to eight meters of slip "deficit," which will be released in the future big earthquakes. If all inferred deficit is released in a single event, it would result in a magnitude eight earthquake, roughly the size of the 1906 San Francisco earthquake.

"In the earthquake business, the past is a key to understanding the present and by comparing data on the timing of past earthquakes on the fault with what we have measured over the last 10 years, we can say with some certainty that the fault is approaching the end of its loading period," said Fialko.

If the next quake is much bigger than the 1994 Northridge quake then costs could easily run in to the hundreds of billions of dollars.

When it does rupture on the San Andreas, such a quake could be as deadly as the 1994 Northridge quake, which struck on an unsuspected hidden fault now called the Northridge or Pico and killed 51 people, injured 9,000 and caused $44 billion in damages.

If you are in a wood frame house that is not perched precariously on a hillside your odds of getting killed are quite low. But if you are on an elevated roadway or some old high building or downstream of some dogdy old dam filled with water then your risks go up. For myself personally I'm more worried about the economic disruption (e.g. the need for electricity and internet to do work).

By Randall Parker    2006 June 25 07:37 AM   Entry Permalink | Comments (4)
Site Traffic Info