Elaine Meinel Supkis
The news that the lower half of the San Andreas fault system might jump 32' is something everyone better take very seriously. This would not only shake up the entire southern half of California if it is a tremendous 8+ mag event, it will destroy the water system that feeds the entire population in the biggest population centers of California.
A jump this big will destroy a lot of cross-fault systems such as the entire water complex.
By Jeremy LovellLONDON (Reuters) - The southern end of the San Andreas fault near Los Angeles, which has been still for more than two centuries, is under immense stress and could produce a massive earthquake at any moment, a scientist said on Wednesday.
Yuri Fialko, of the Scripps Institution of Oceanography at La Jolla, California, said that given average annual movement rates in other areas of the fault, there could be enough pent-up energy in the southern end to trigger a cataclysmic jolt of up to 10 meters (32 ft).
"The observed strain rates confirm that the southern section of the San Andreas fault may be approaching the end of the interseismic phase of the earthquake cycle," he wrote in the science journal Nature.
A sudden lateral movement of 7 to 10 meters would be among the largest ever recorded.
Not only would that be very big, it is approaching the level of the shift that launched the Boxing Day disaster. I looked at the earthquake maps run by the geological survey and as usual, it shows many micro quakes along the upper arm of the San Andreas and there is the usual activity at the Salton Sea segment which lies below the San Andreas but the middle section which is in red at the map above, here, that is onimously silent. We had a few vigorous quakes this year right at the ocean at the very top of the fault line and at the very base but nothing in the middle above a 4.5 Mag.
Click on image to enlarge
All of the California water systems feeding into the biggest population centers cross over or run right alonside this faultline. A 32' jump sideways will pretty much destroy the system. I know they don't want anyone to panic but just look at the map here.
People have no idea how much water they use daily or how much one has to have at hand. I lived without pumped water for many years and had to go to a spring and fill containers and drag them home. I was very careful about how much water I used and even so, for a family of just three very thrifty, careful people, it was 60+ gallons a week. And I do mean 'thrifty' with precious water! I have a 250 gallon water storage tank which we installed eight years ago and that made life easier for I could use up to 100 gallons a week.
Most people use that much per person every few days!
If there is no water, there will be no way to easily put out fires. And fires are always earthquakes' handmaidens of death. The shredded remains of our National Guard and their vehicles will have a hellishly hard time getting over, too, since every major and minor road will be very disrupted. We aren't talking about a minor jag in the road. 32' is a great distance and of course, the earth will be full of hillocks and dales as well as one side being significantly higher or lower than the other.
Yesterday, a similar story, only about the even more vulnerable New Madrid zone.
Associated PressBLYTHEVILLE, Ark. - An earthquake expert with the U.S. Geological Survey says many residents and officials in northeast Arkansas are setting themselves and their neighbors up for a worse disaster by underestimating the results of a quake in the region.
"This is a different kind of earthquake," said Gary Patterson of the United States Geological Survey Center for Earthquake Research and Information at the University of Memphis in Memphis, Tenn.
"This is not a California earthquake," Patterson said last week at a meeting of the Arkansas Gov.'s Earthquake Advisory Council. "There are some basic differences here that drive the hazard level up."
Patterson, who serves as information director and geologist for the Memphis center, said that, unlike faults in California, the New Madrid Seismic Zone contains three to five major fault segments lying over the top of each other in a relatively small area.
The zone stretches from northeast Arkansas and northwest Tennessee up into southeast Missouri, far western Kentucky and southern Illinois.
Big earthquakes have happened before and will happen again in this area, he said, citing the series of quakes in 1811-1812 that were the strongest ever to occur in the continental United States.
But he said even a 6.5-magnitude quake has the potential of doing an enormous amount of damage in Blytheville and Mississippi County, Patterson said.
"It won't take a catastrophic earthquake to do catastrophic damage," he said.
They all have good reason to fret. The earth significantly rearranged itself a year and a half ago. The USA has been spared large quakes unlike many other places but the action on the Pacific Plate most certainly impacts our continent! The soil conditions in the Mississippi watershed are very prone to liquification. And again, if it is a major event, all water systems will fail as well as the electrical grid which, by the way, is very easily brought down if the San Andreas moves a tremendous amount!
In the midwest, brick building which are often quite old abound. Unlike California which regularily loses older buildings to previous earthquakes. This is something we are not able to fix because we are spending all our excess funds trying to get the Iraqis to stop acting as if they are the Hungarians fighting the Soviet Union!
Granite is an igneous rock and is formed from magma. Granite magma has many potential origins but it must intrude other rocks. Most granite intrusions are emplaced at depth within the crust, usually greater than 1.5 kilometres and up to 50 km depth within thick continental crust.
The origin of granite is contentious and has led to varied schemes of classification. Classification schemes are regional; there is a French scheme, a British scheme and an American scheme. This confusion arises because the classification schemes define granite by different means. Generally the 'alphabet-soup' classification is used because it classifies based on genesis or origin of the magma.
I wonder what is at the 10 km level. Many earthquakes are at that depth. The biggest shakers seem to like that depth a lot. It must be where there is some disruption or change in temperature.
It is the thickness of the crust at sea, for exmple.
The Earth's crust is about 35 kilometers thick under the continents, but averages only some 7-10 kilometers beneath the oceans. The continental crust is composed primarily of crystalline basement; stable igneous and metamorphic rocks such as granulite, granite and various other intrusive rocks. Oceanic crust is composed primarily of basalt, gabbro and peridotite.The crust floats on the asthenospheric mantle, which is convecting due to the forces of plate tectonics. The mantle, which extends to a depth of nearly 3,000 kilometers is the source of all magma. Most of the magma which forms igneous rocks is generated within the upper parts of the mantle at temperatures estimated between 600 to 1600 °C.
Melting of rocks requires temperature, water and pressure. The mantle is generally over 1000 to 1200 °c beneath the crust, at depths of between 7 and 70km. However, most magma is generated at depths of between 20 and 50 km. Melting begins because of upwelling of hot mantle from deeper portions of the earth, nearer the Planetary core; because of water driven off subducted oceanic crust at subduction zones (providing water to lower the melting point of the rocks) and because of decompression caused by rifting.
People don't like living in fear. This is understandable. But living foolishly isn't understandable. When the inevitable, and this is totally inevitable, happens, it is the responsibility of everyone to be equally prepared. We all saw the grim suffering of so many people in New Orleans. In particular, they needed water. Hope everyone in California is being warned about the need to have at least 50 gallons stored in an earthquake-proof manner. For water will be more precious than gold, when it happens. And forget buying gas and leaving quickly.
The electricity will probably be down, too.
Further news, scientists find the earth is definitely heating up.
WASHINGTON (AP) -- The Earth is the hottest it has been in at least 400 years, probably even longer.The National Academy of Sciences, reaching that conclusion in a broad review of scientific work requested by Congress, reported Thursday that the "recent warmth is unprecedented for at least the last 400 years and potentially the last several millennia."
This is a tricky issue. I know for a fact that disrupting Nature always sets into motion unintended consequences. This is why we ought to be very careful. But the ultimate arbeiter of global warming is our sun. It has been particularily active, frighteningly so, recently! If the sun decides to go into Ice Age mode, then forget global warming.
On the other hand, polluting everything is bad. B-A-D. So there is no excuse, is there?
This [http://www.post-gazette.com/pg/06160/697012-115.stm] is an interesting article on the connection between global warming and increased earthquake/volcanic activity.
"It's unavoidable that glacial retreat will induce tectonic activity," says geoscientist Allen Glazner of the University of North Carolina, Chapel Hill.
...
Instead, the world-wide melting of glaciers portends a seismically active future because of isostatic rebound and also because the meltwater from liquefying glaciers adds mass atop oceanic plates. That creates a teeter-totter effect, further destabilizing the planet's crust. "Recent findings reinforce the idea that the solid earth and the climate are inextricably linked," says Prof. Glazner.
That link has reared its ugly head in the past, especially during periods of rapid climate change such as the end of ice ages. When ice sheets retreated 10,000 years ago, for instance, Iceland experienced a surge in volcanic eruptions. Volcanoes in the Mediterranean, Antarctica and eastern California also seem to have been awakened by retreating ice.
When he analyzed 800,000 years of activity from about 50 volcanoes in eastern California (the age of rocks formed from volcanic ash can be determined by radioactive dating), Prof. Glazner found that "the peaks of volcanic activity occurred when ice was retreating globally. At first I thought it was crazy, but other scientists also found evidence that climate affects volcanism." The likely mechanism: glacial retreat lifts pressure that had kept the magma conduit closed.
Posted by: Iowan | June 23, 2006 at 09:17 AM
Iowan, I have suggested exactly that in the past! I agree that removal of ice from any significant area will trigger earthquakes and volcanoes.
Posted by: Elaine Meinel Supkis | June 24, 2006 at 02:01 PM
'I know for a fact that disrupting Nature always sets into motion unintended consequences."
Earthquakes and volcanoes happen if you only sit there and watch. Note that these occurred even before there were humans around to cause them.
Posted by: Jsmith | June 29, 2006 at 09:13 AM