john's picture

Update July 19, 2010: Earthquake Forecasts for San Diego and Los Angeles

In a blog posted on July 8, 2010 ("A New Type of Forecast') we provided figures showing the time history of magnitude M>7 earthquakes within 150 miles of San Diego and within 1 year of the time indicated on the horizontal axis. 

it seems timely to update that figure, and to provide another such forecast for the Los Angeles area. 

john's picture

Is Southern California's San Andreas Fault the Hole in Mogi's Donut?

In 1969 the famous Japanese seismologist Kiyoo Mogi (1929-) wrote a paper entitled:  "Some Features of Recent Seismic Activity in and near Japan.  Activity before and after Great Earthquakes."  Published in the Bulletin of the Earthquake Research Institute, Japan [1], it described patterns of smaller earthquakes that precede great earthquakes. 

jrholliday's picture

Why So Many Earthquakes Lately?

Why has the San Diego region experienced so many earthquakes lately? KPBSSanDiego speaks to a seismologist from the Scripps Institution of Oceanography about what's causing all the recent quakes.

john's picture

A New Type of Forecast

The recent April 4, 2010 M7.2 Mexicali earthquake has been the subject of considerable analysis and speculation.  It occurred at a location of high probability in the California border region with Mexico, as shown by the Open Hazards viewer (available under the Tools tab).  And while the baseline forecast on this web site does an excellent job of forecasting locations of major events, we are continually seeking to improve our forecast technology, particularly to better capture times of heightened probability.

jrholliday's picture

Earthquake Physically Moved City

From the news sources at MSNBC:

PASADENA, Calif. - The strong Easter earthquake physically moved the border city of Calexico.

NASA data released Wednesday revealed the magnitude-7.2 quake shifted the Calexico region up to 2 1/2 feet in a southerly direction.

The quake, centered in Baja California, caused $100 million in damage to California, primarily in Calexico.

jrholliday's picture

Pacific Northwest At Risk For Mega-Earthquake

Science Daily Headlines reports on research by Oregon State University marine geologist Chris Goldfinger showing that earthquakes of magnitude 8.2 (or higher) have occurred 41 times during the past 10,000 years in the Pacific Northwest. By his extrapolation, there is a 37% chance of another major earthquake in the area in the next 50 years that could exceed the power of recent seismic

jill's picture

What would a really “Big One” look like?

People who live anywhere along the Earth’s tectonic plate boundaries (the so-called “ring of fire” know that at any time  “the big one” – a really, really large, damaging earthquake – could happen. The largest earthquake in recorded history was a 9.5 event along the coast of Chile in 1960. The second largest was a 9.2 along the southern coast of Alaska in 1964. Since January, 1700, only six events have occurred that were 9.0 or larger – one of them as recently as 2004 in Sumatra, Indonesia.

jrholliday's picture

So Many Earthquakes! The End Is Nigh!

Michael Reilly from DiscoveryNews writes about the unusually high number of earthquakes this year:


After the magnitude 6.9 earthquake in China early Wednesday morning, things are starting to look a little bleak on this planet of ours. This year is only three and a half months old, and yet there have been devastating earthquakes in Haiti, Chile, and China.

john's picture

Today's Magnitude 6.9 Earthquake, Yushu, China

An earthquake measuring 6.9 on the Moment-magnitude scale has struck southern Qinghai,
China, near the city of Yushu in the Tibet Autonomous Region.  Using the Hazard Viewer tool
on this web site, together with the Recent Earthquakes display, it can be determined that the ground
shaking resulting from the earthquake in Yushu was between 8% g and 12% g, equivalent
to Modified Mercalli Intensity V to VI.  Shaking of this intensity is enough to collapse some buildings
constructed of unreinforced masonry, as might be common in the region.


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