john's picture

Chile Earthquake Seismic Gap

One of the theories about earthquake occurrence over the years is that seismic gaps develop between major and great earthquakes, and are eventually filled.  With that in mind, it is interesting to plot the approximate slip planes for both the M8.8 earthquake of 27 February, 2010, and today's M8.2 earthquake of April 1, 2014.

john's picture

Magnitude M8.2 and Tsunami, Iquique Chile, April 1, 2014

Earthquake in Chile with tsunami watch and warning.  Areas of the Pacific should take precausions, including Hawaii and Japan, among other areas.  Depth shallow, about 10 km.  Screenshot of earthquake location below, with forecast contours for M>6.5.  The forecast was computed at midnight last night - forecasts are updated every night at midnight California time.

john's picture

Is Earthquake Insurance Worth It?

We often get asked this question.  Here is one opinion after the recent March 28, 2014 Brea/La Habra (Los Angeles) California earthquake.

john's picture

Magnitude 5.1 Earthquake Los Angeles, March 28, 2014

The earthquake occurred last night at about 9:09:42 pm PDT. Below are some screenshots and simple analysis of future earthquake risk taken from the Hazard Viewer.

The epicenter was closest to the Puente Hills mapped fault:

john's picture

M4.4 Earthquake near Los Angeles, CA March 17, 2014

(Updated 10:45 PDT 3/17/2014)

A moderate earthquake occurred this morning at 0625 am PDT.  It was centered at a location 9 km NNW of Westwood, CA, where the University of California at Los Angeles is located.  A screenshot from the Open Hazards Hazard Viewer is shown below:

john's picture

M6.9 Earthquake Offshore Eureka, California, March 10, 2014

The earthquake occurred at 0700 PDT, 7 hours after the forecast for the figure below was computed (it is computed at midnight).  Using the hazard viewer, we can draw a circle of 100 km radius around the epicenter.  The forecast table (lower left corner) indicates that there was a 25% chance of an M>6 earthquake within the next year, and a 91.6% chance within the next 3 years. 

(Update on March 11:  The magnitude has been further refined to 6.8 rather than 6.9)


Steve's picture

French Omelet

The French Riviera enjoys a wonderful climate. No surprise that all those movie stars, sports heroes, and super models hang out in places like Monaco, Nice, Cannes and Fréjus.   OK --  maybe not so many rich and famous spend time in Fréjus, but it is the setting for today’s blog, so bear with me.

john's picture

South Carolina Earthquake M4.1: More Thoughts

There will be the inevitable speculation about whether the earthquake yesterday in South Carolina was related to fluid reinjection.  One way to think about this is to look at the drilling sites in the United States that may have reinjection wells associated with them.  I show such a map below that originates from here.  You can see that the number of wells on the border of South Carolina and Georgia (where the earthquake occurred) is rather low, by comparison with other parts of the country. 


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