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Topic: Parkfield earthquake

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In the News (Tue 16 Jul 19)

  Lessons learned at Parkfield   (Site not responding. Last check: 2007-11-04)
While the timing of the major earthquakes at Parkfield has not been entirely regular, it is certainly not random, and there is enough consistency to support the concept that this part of the fault fails at relatively consistent intervals with earthquakes of a predictable size.
GPS measurements have shown that the extent of inter-seismic slip is generally comparable to the extent of seismic slip, and is concentrated in parts of the fault that slipped the least during seismic events.
There were two main areas of strong shaking, one close to the epicentre of the 1934 and 1966 earthquakes, and one at the southeastern end of the zone, near to the epicentre of the 2004 earthquake.
www.mala.bc.ca /~earles/parkfield-oct05.htm   (984 words)

Determining the average rate of recurrence of strong earthquakes on a fault is a key element in long-term hazard assessment.
However, a physically reasonable model that incorporates the somewhat "off-schedule" Parkfield earthquake of 1934 leads to a much higher probability for Parkfield within the next few years, and it is this calculation on which the current Parkfield prediction experiment is based.
Earthquakes are produced by sudden slippage on surfaces of failure ("faults") that relax elastic strains that have accumulated over long periods of time due to the relative movements of the earth's crustal plates.
www.johnmartin.com /earthquakes/eqpapers/00000074.htm   (1076 words)

 Parkfield: Introduction
The goal is to observe the fault and surrounding crust at close range at the time before, during and after an earthquake, to better understand the earthquake process and provide a scientific basis for earthquake prediction.
Led by the USGS and the State of California, the experiment's purpose is to better understand the physics of earthquakes - what actually happens on the fault and in the surrounding region before, during and after an earthquake.
Available data suggest that all six moderate-sized Parkfield earthquakes may have been "characteristic" in the sense that they all ruptured the same area on the fault.
quake.wr.usgs.gov /research/parkfield/index.html   (425 words)

 Earthquake Prediction Information
Earthquake magnitude and timing are controlled by the size of a fault segment, the stiffness of the rocks, and the amount of accumulated stress.
One well-known successful earthquake prediction was for the Haicheng, China earthquake of 1975, when an evacuation warning was issued the day before a M 7.3 earthquake.
Earthquake prediction is a popular pastime for psychics and pseudo-scientists, and extravagant claims of past success are common.
www.geophys.washington.edu /SEIS/PNSN/INFO_GENERAL/eq_prediction.html   (1204 words)

 Statistical aspects of Parkfield earthquake sequence and Parkfield prediction experiment
Testing the research hypothesis (quasi-periodic recurrence of characteristic earthquakes) against the null hypothesis is difficult for several reasons: the characteristic quasi-periodic models have not been clearly specified at Parkfield; the earthquake catalog data are of mixed quality; and the rules by which Parkfield was selected as a "special" area are not specific.
We formalize the Parkfield hypothesis as presented by Bakun and Lindh (1985) and the null hypothesis.
Earthquakes' spatial distribution is inhomogeneous: their concentration in a few fault segments increases the probability that a random earthquake sequence will be counted as a characteristic series.
scec.ess.ucla.edu /~ykagan/parkf.htm   (6695 words)

 2004 Parkfield earthquake
The NCEDC is serving as a collection point for data related to the 2004 Parkfield earthquake.
Data from the Parkfield mainshock as recorded by the string in the SAFOD Pilot Hole.
Strong motion data from this earthquake is available from the CISN Engineering Data Center.
www.ncedc.org /2004parkfield.html   (1135 words)

Although 130 years have passed since the 1857 earthquake, there is little reason to anticipate a repeat of the 1857 earthquake in the next several decades.
Crustal deformation measurements along the San Andreas fault southeast of Parkfield indicate that relative motion of the Pacific and North American plates is straining the regions at a rate corresponding to 3 cm per year of right-lateral slip on the San Andreas fault.
Sieh's intensity map for the March 3, 1901, Parkfield earthquake suggests that the area of strong shaking (modified Mercalli intensity VI or greater) was about twice that of the 1966 Parkfield earthquake, suggesting a somewhat larger magnitude for 1901 than for 1966.
www.johnmartin.com /earthquakes/eqpapers/00000075.htm   (1765 words)

 A Strong Earthquake Shakes Central California Fulfilling USGS' Parkfield Forecast
Calling it "one of the most significant earthquakes in the history of seismology," William Ellsworth, chief scientist for the USGS Earthquake Hazards program in California, today commended efforts to densely instrument the location of the September 28th Parkfield 2004 Earthquake.
Tuesday's earthquake, dubbed Parkfield 2004, is the seventh in a series of historically known earthquakes occurring on the same part of the San Andrea Fault since 1857.
Parkfield 2004 ruptured the San Andreas from southeast to northwest.
www.scec.org /education/040930parkfield.html   (868 words)

 Seismological Studies at Parkfield, California
At Parkfield the achievable location accuracy to which a hypocenter can be specified as well as the predictability of its occurrence time appear to be uniquely favorable for in-situ fault zone measurements.
The spatial distribution of hypocenters in the Parkfield area is shown to be consistent with this model, and with a hierarchical clustering of asperities having a discrete rescaling factor of about 20.
The M4.6, M4.2, M4.7, and M5.0 earthquakes which began to occur subsequent to 1992 and their aftershocks zones are shown as ellipses A, B, C, and D respectively.
www.seismo.berkeley.edu /seismo/annual_report/ar97_98/node15.html   (4086 words)

 Parkfield Home Page
Parkfield experienced a magnitude 6.0 Earthquake on September 28, 2004.
They came to hunt and gather acorns, and named the valley in which Parkfield rests "Cholame," which means "the beautiful one." The first white settlers arrived in the area in 1854 and were followed by a steady stream of homesteaders.
However, Parkfield's prosperity was short lived as the mines played out and water flooded the coal mine.
www.parkfield.com   (343 words)

 CurEvents.com - A Global Current Events Discussion Forum - Was the Parkfield earthquake a foreshock to a much larger ...
The earthquake is called the Fort Tejon earthquake because that is the area that suffered the largest measured displacement of the fault.
Alternatively, the characteristic earthquake might stop at the en echelon offset and, by analogy to the triggering mechanism of the early foreshock of ML 5.0 in 1934, increase the right-Lateral shear stress on the fault southeast of the rupture zone.
In California, tides may vary the rate of earthquakes at most one or two percent; the overall effect of the tides is smaller, he said, because the faults studied are many miles inland from the coast and the tides are not particularly large.
www.curevents.com /vb/showthread.php?t=989   (8178 words)

 Parkfield earthquake - Wikipedia, the free encyclopedia
The Parkfield earthquake is a name given to any large earthquake that occurs in the vicinity of the town of Parkfield, California.
Earthquakes may occur regularly here because the location is about midway on a fault segment between a locked segment to the south (last major earthquake 1883) and a creeping segment to the north where two tectonic plates are continuously moving without major earthquakes.
The epicenter of this earthquake is (by various sources) believed to be somewhere in the region from Cholame to Parkfield, a location at the extreme northern end of the locked portion of the fault and at the southern end of the rapidly periodic segment.
en.wikipedia.org /wiki/Parkfield_earthquake   (669 words)

 SignOnSanDiego.com > News > State -- Another substantial quake, not an aftershock, rattles Central California
The earthquake struck at 3:54 p.m., 17 miles northeast of Arvin, said Anthony Guarino, a seismic analyst for the California Institute of Technology in Pasadena.
The Parkfield and Arvin quakes would be examined by scientists who for the past decade have been looking at links between separate quakes in California that occur far apart, Guarino said.
The Parkfield earthquake and its aftershocks have not caused any major damage or injuries, but they could be a boon to researchers who hope intense scrutiny of the state's earthquake capital may help predict future temblors.
www.signonsandiego.com /news/state/20040929-1812-wst-califquakes.html   (734 words)

 Seismo-Watch Noteable Earthquake, Parkfield M 6.4 earthquake, March 3, 1901
The quake was centered near Parkfield, then a remote farming and ranchland community, and caused chimneys to topple and windows to shatter over a wide area.
At Parkfield, three houses were twisted out of shape and one was almost wrecked.
The quake occurred in nearly the same location as two quakes prior to it (1857 and 1881), but it was not till the 1980's and after three more (1922, 1934, 1966) of similar magnitude that a pattern of every 21-22 years was discovered.
www.seismo-watch.com /EQSERVICES/NotableEQ/Mar/0303.1910.Parkfield.html   (218 words)

 CISN: 2004 Parkfield Earthquake
Because of the timing and distance of this event with the 2004 Parkfield earthquake, there may be a correlation between the events.
Sept 28: This earthquake is the anticipated Mw 6.0 on the San Andreas fault.
This earthquake occurred at 10:15 AM PDT on September 28, 2004 had a hypocenter of 35 degrees, 49 minutes north, 120 degrees 22 minutes west, and a depth of 8 km or 5 miles.
www.cisn.org /special/evt.04.09.28   (789 words)

 Maps for Parkfield
Based on the analysis of historical seismicity, the USGS "predicted" that an earthquake of ~M6 would occur in Parkfield between 1987 and 1993.
Although the expected earthquake has not yet occurred, Parkfield is one of the more likely sites in California for a moderate earthquake.
Kagan, Y., Statistical aspects of Parkfield earthquake sequence and Parkfield prediction experiment, Tectonophysics, 270, 207-219, 1996.
www.ncedc.org /oldeqs/Parkfield.html   (301 words)

 CISN: 2004 Parkfield Earthquake - Comparison with the forecast
The Mw 6.0 earthquake on the San Andreas fault on 9/28/2004 at 10:17AM PDT fulfilled some, but not all elements of the original 1985 earthquake forecast for Parkfield (see the Parkfield Prediction Experiment for background on the scientific basis and seismic history of the region).
Analysis of the aftershocks and rupture models of the 2004 Parkfield indicates that it ruptured along the same section of the fault in an earthquake of similar magnitude to the earlier members of the Parkfield earthquake series.
This "Long-Term Prediction" was evaluated and endorsed by the National Earthquake Prediction Evaluation Council in 1985, and the State of California was notified by the USGS that there was a high probability of about M 6 earthquake in the Parkfield region in the 1985-1993 interval.
www.cisn.org /special/evt.04.09.28/parkfield.html   (668 words)

 Geotimes — September 2004 — Parkfield finally quakes
The earthquake's epicenter is located 7 miles southeast of Parkfield, and it is the largest Parkfield has felt since 1966 (though the region has experienced small earthquakes since then).
The activity at Parkfield "may be winding down," she says, and the next earthquake in the series may occur 50 years from now.
From a historic viewpoint, this type of earthquake also may have triggered a larger event in 1857, known as the Fort Tejon earthquake, that ruptured several hundred miles of the San Andreas Fault starting from Parkfield and moving to the south.
www.geotimes.org /sept04/WebExtra092804.html   (613 words)

 SCEDC | ParkField Earthquake (1966)
What is more significant about the 1966 Parkfield earthquake is that the USGS used it to suggest a 21-to-22-year periodicity of magnitude 6 earthquakes at Parkfield.
In April 1985, the USGS issued a prediction that an earthquake of approximately magnitude 6 would occur before 1993 on the San Andreas fault near Parkfield, which gained this little town of 34 inhabitants national fame as being the site of the first officially recognized scientific prediction of an earthquake in the United States.
The year 1993 came and went with no magnitude 6 earthquakes in the area, though Parkfield did experience a magnitude 4.7 quake on October 20, 1992, a magnitude 4.4 on April 4, 1993, a magnitude 5.0 on November 14, 1993, and a magnitude 4.9 on December 20, 1994.
www.data.scec.org /chrono_index/parkfiel.html   (322 words)

 Still waiting for the 1987 Parkfield earthquake   (Site not responding. Last check: 2007-11-04)
Another similar earthquake was expected to occur at Parkfield by around 1987, but it still hasn’t happened, and the gap is now 36 years.
Murray and Segall (2002) have estimated the rate of strain accumulation on the Parkfield segment of the SAF, and they conclude that the most of the strain released by the 1966 quake had re-accumulated by 1981, and that there is a 95% probability that another large quake should have occurred by 1987.
On the other hand, they also calculate that two small earthquakes in the Parkfield area in 1992 and 1994 (around M4) actually increased strain on the Parkfield rupture zone, essentially countering the delaying effect of the Coalinga quake.
www.mala.bc.ca /~earles/parkfield-sep02.htm   (631 words)

Parkfield is the self-proclaimed earthquake capital of California.
If you tacked a dollar to the wall in the past know that it went to a good cause; if you are coming to Parkfield consider helping to repopulate the wall knowing that it eventually will go to a good cause.
Parkfield is known as the earthquake capital because for recent history it has had a 6 point or better earthquake about every 23 years (it's overdue for the next one; and scientists have recently indicated the past sequences could well be just chance).
tomsdomain.com /travel/short/parkfield.htm   (483 words)

 Earthquake Clouds and Short Term Prediction
The Parkfield [3] earthquake prediction experiment is famous because the USGS proposed an odd view that large earthquakes would repeat there every 22 years.
"After the 1966 Parkfield earthquake, research increased significantly on crustal deformation and small earthquakes activity for this segment of the San Andreas fault, and analysis of the resulting data has clarified the relation between fault slip and minor seismicity both at the time of the 1966 shock and subsequently" [4].
The USGS used 60 geodetic survey lines measured by precise laser ranging, analyzed historic data [5], and obtained a conclusion: "At Parkfield, the duration of the seismic cycle is 22 years, the length of the Parkfield fault section is 25-35 kilometers, and the 'large' earthquake is a magnitude 6 shock" [4].
quake.exit.com /A030316.html   (1515 words)

 ScienceDaily: Strong Earthquake Shakes Central California Fulfilling USGS' Parkfield Forecast
Another major earthquake is expected when the San Andreas finally breaks loose.Image by Robert Simmon and Jesse Allen, based on Shuttle Radar Topography Mission data provided by the USGS Seamless Data Distribution System.
Earthquakes Kill Thousands In 2003; Deadliest Year Since 1990 (January 26, 2004) -- According to the U.S. Geological Survey (USGS), 2003 closed as the deadliest year for earthquakes since 1990, 25 times more fatal than 2002; 43,819 deaths have been reported for the past year, as...
Earthquake liquefaction -- Earthquake liquefaction, often referred to simply as liquefaction, is the process by which saturated, unconsolidated soil or sand is converted into a suspension during an earthquake.
www.sciencedaily.com /releases/2004/10/041001090002.htm   (2195 words)

 PARKFIELD / 4.2 earthquake hits Monterey County
An earthquake with an estimated magnitude of 4.2 struck Sunday afternoon near Parkfield in Monterey County along the San Andreas fault, according to officials.
The earthquake, which was followed by smaller aftershocks, was felt from Santa Margarita in the south to King City in the north, according to the U.S. Geological Survey Web site.
The earthquake follows an earthquake in the area on Sept. 28 with a 6.0 magnitude that was long-anticipated to happen by the Geological Survey based on the 150 year history of the fault.
sfgate.com /cgi-bin/article.cgi?f=/c/a/2004/11/29/BAGDHA2C0C1.DTL   (170 words)

 Earthquake Authority Monitors Parkfield Earthquake   (Site not responding. Last check: 2007-11-04)
The California Earthquake Authority is monitoring events in Central California following Tuesday's 6.0 magnitude earthquake that struck near Parkfield at 10:15 a.m.
The CEA Earthquake Response Manager is coordinating with participating insurance company claims representatives to determine what damage, if any, might have occurred to residential property insured by the CEA as a result of the quake.
Bush said the earthquake is a reminder to all Californians to check the earthquake safety of their homes and their earthquake preparedness plans.
www.insurancejournal.com /news/west/2004/09/28/46335.htm?print=1   (191 words)

 EO Newsroom: New Images - Parkfield Earthquake
On September 28, 2004 a magnitude 6.0 earthquake struck Central California near the town of Parkfield.
The prediction was based on a sequence of 6 similar earthquakes that occured every 22 years (on average) from 1857 to 1966.
In anticipation of this earthquake, geologists placed a large and varied suite of instruments along the Parkfield segment of the San Andreas Fault.
earthobservatory.nasa.gov /Newsroom/NewImages/images.php3?img_id=16684   (241 words)

 California Geological Survey - Earthquakes - Displacement Particle Motions, Parkfield Earthquake of 28 Sep 2004
To illustrate the horizontal ground displacement at selected strong motion station locations in the Parkfield, CA area as a result of the 28 Sep 2004 earthquake.
Ground motions were measured as north-south and east-west components and combined to show how a particle at a given location would move in two dimensions as a result of the earthquake.
Such measurements may be used to help interpret the kinetics of an earthquake event in relation to other factors.
ceres.ca.gov /calsip/catalog/BrowseRecord.epl?id=29302   (206 words)

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