Posted on 06/23/2010 7:42:38 PM PDT by NormsRevenge
The magnitude 7.2 earthquake that gave San Diego County a long, hard shake on Easter Sunday shifted areas of the earth's crust up to 31 inches in Calexico, and by as much as 10 feet near the temblor's epicenter in northern Baja, says data released today by NASA.
The Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) data also suggests that there was some surface rupturing along the border of Imperial and San Diego counties, where lots of aftershock activity continues to occur almost three months after the mainshock.
The new findings are largely based on an airborne radar mapping program that searches for movement along the San Andreas fault and related systems, all which could produce significant shaking in San Diego County.
"Each UAVSAR flight serves as a baseline for subsequent quake activity," NASA said in a statement. "The team estimates displacement for each region, with the goal of determining how strain is partitioned between faults. When quakes do occur during the project, the team will observe their associated ground motions and assess how they may redistribute strain to other nearby faults, potentially priming them to break.
"Data from the Baja quake are being integrated into JPL's QuakeSim advanced computer models to better understand the fault systems that ruptured and potential impacts to nearby faults, such as the San Andreas, Elsinore and San Jacinto faults."
The Easter Sunday quake, which is officially known as the El Mayor-Cucapah event, erupted on April 4th on the southern section of the Borrego fault, producing seismic energy that rapidly fanned across San Diego County. The satellite data proves that it also affected the earth's crust in different places.
"That amount of shifting is consistent for a quake of that size," said Bob Dollar, a seismologist at USGS.
Oh no... Global Cracking.... the wacko left new mantra
Hmmmm, with the Earth rising 10’ instead of sinking that means there is less chance of the Sea of Cortez from filling up the Salton Sea.
I think that is a lateral shift of 10’....
I would expect there was some movement vertically as well.
Both up and down.
This is an upthrust fault. It Looks like the Pacific plate decided to overrun the North American plate.
When you move that much earth between 31 inches and ten feet I can only wonder where the stress has been transferred.
The USGS map shows that the area around Ocotillo has become more active as the area in Mexico appears to be less active. If this trend continues, it looks like Escondido may be in for a ride soon.
map here: http://earthquake.usgs.gov/earthquakes/recenteqscanv/FaultMaps/116-33.html
Hmmmmmm ..?? Shall we have a contest to name our new “island” ..?? ROTFLOL!!!
I wish there were some pictures of the moved earth.
I will say my earthquake software has been measuring hundreds and hundreds of quakes in that area recently.
Uninhabited Aerial Vehicle?
Really?
Has NASA gone completely nuts with PC?
Is there something wrong with having an "Unmanned Aerial Vehicle" that the term couldn't get past NASA's fembot censors?
Gag me with a spoon...
Figure 1. Overview of the UAVSAR interferogram of the magnitude 7.2 Baja California earthquake of April 4, 2010, overlaid atop a Google Earth image of the region. Major fault systems are shown by red lines, while recent aftershocks are denoted by yellow, orange and red dots. Image credit: NASA/JPL/USGS/Google › Larger view
NASA Radar Images Show How Mexico Quake Deformed Earth
http://www.jpl.nasa.gov/news/news.cfm?release=2010-208
more images,, lots of pretty colors
NASA UAVSAR
http://uavsar.jpl.nasa.gov/
Why we're getting so many earthquakes
*********************************EXCERPT***************************************
The main earthquake moved the ground 12 to 15 feet in places,
************************ ****snip*****************************
It occurred along the southernmost portion of the Elsinore Fault Zone, which has not had a major earthquake in the past 100 years or so. Because of the location of the Mw 5.7 aftershock , CEPEC believes that the probability of a larger event on the Elsinore Fault or the San Jacinto Fault has increased considerably, and will remain so for several days, although the absolute probability remains low, on the order of one percent.
Microearthquake study of the Elsinore fault zone, Southern California
DEPARTMENT OF GEOLOGICAL SCIENCES AND INSTITUTE OF GEOPHYSICS AND PLANETARY PHYSICS UNIVERSITY OF CALIFORNIA, RIVERSIDE, RIVERSIDE, CALIFORNIA 92502
Abstract
Microearthquakes along the Elsinore fault zone, southern California, were monitored during the summer and fall of 1972. Four arrays of at least five portable, high-gain, seismographs were operated for about 12 days each from the vicinity of Corona to just north of the Mexican border. Over 5,000 hr of noisefree records were accumulated and analyzed. The recorded rates of seismic activity show a marked increase going from north to south along the fault— 0.5 events per day in the vicinity of Lake Elsinore to 3.7 events per day in the south near Monument Peak. Fifty-three events located, assuming a four-layer crustal-velocity model, show considerable scatter along the fault and are generally very shallow, averaging 3.3 km below sea level. A signal duration (D) versus magnitude (M) relationship was found: M = –1.9+2.0 log D. First motions of the located earthquakes indicate a complex pattern of faulting along the Elsinore fault zone. In comparison to the San Jacinto Fault to the east, the Elsinore Fault shows very little strike-slip displacement and is a seismically quiet area except for a localized area of east-west faulting in the far south near Vallecito Mountain.
Footnotes
* Present address: Harding-Lawson Associates, 55 Mitchell Boulevard, San Rafael, California 94902.
Quake would be county's Katrina; Elsinore fault said more dangerous locally than San Andreas
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By: DAVE DOWNEY - Staff Writer | Posted: October 9, 2005 12:00 am |
A Category 4 hurricane may never pummel Riverside County. That's hardly reason to take comfort, however, because plenty of other hazards have potential to injure and kill droves of people and cause widespread property damage in this sprawling, rapidly growing region, said Mary Moreland, the county's emergency services director.
Earthquakes on the San Andreas, Elsinore and San Jacinto faults, wind-driven wildfires in the Cleveland and San Bernardino national forests, dam breaks at Diamond Valley Lake, Lake Perris and Lake Skinner, flooding from winter downpours and an accident at the San Onofre nuclear power plant all pose ominous threats, Moreland said in a recent interview.
Disaster response officials fear a major quake most, she said, because not only would it exact widespread destruction on its own, it could unleash other threats such as forest fires and collapsing dams.
"An earthquake would be our Katrina," Moreland said.
Lucy Jones, lead Southern California scientist for the U.S. Geological Survey in Pasadena, said the extent of damage from the Big One that so many people fear will depend largely on where it strikes and when.
"If it happens during the middle of the night, we are going to be much better off than if it happens during the rush-hour or during the day when people are at work in their offices," Jones said. "If it happens during a Santa Ana, we are going to be much, much worse off than we will be if it happens during a more benign weather condition. That's the real nightmare."
The Santa Ana scenario is scariest of all because a quake could spark fires and hurricane-force winds could fan flames into unstoppable firestorms, Jones said. Battling wind-driven blazes is tough under any circumstance, she said, let alone with roads knocked out and air tankers snapped in pieces like toy airplanes.
With that quake in Yuma a few weeks ago I’m wondering if we are seeing is an earthquake storm. One quake releases tension only to move the stress point further up along the fault until it brakes and so on. Is Los Angeles next?
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