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Here we show the changes in earthquake probabilities following friday's M7.3 earthquake off the coast of Tohoku, Japan.  As reported earlier, a 1 meter tsunami was observed on the coast near Arahama, Japan. In this update, we show both the updated timeseries of probability, and the changes in spatial contours of probability.  We adopt the same conditions for the spatial and temporal probabilities as shown in previous blogs, to facilitate comparisons.

It was just reported that a M7.3 earthquake struck at 8:18:25 GMT off the eastern coast of Japan, in the area of the March 11, 2011 event.  A 1 meter tsunami was reported as well, with at least 1 M6.2 aftershock.  We had been expecting an event rather like this one, as shown by the figure below. I am still at the AGU meeting where a most interesting set of presentations on the March 11 event were given yesterday. 

Latest word is that more than 22,000 attendees are expected at this years' meeting.  I went to some interesting talks on the March 11, 2011 M9 Tohoku, Japan earthquake this morning.  It seems that there was evidence of slow ("aseismic") slip prior to the earthquake, according to Yoshihiro Ito and colleagues from Japan.  There were two events in the years preceeding the mainshock. Both events were seen on ocean bottom pressure transducers, and on-shore volumetric strainmeters.

About 19,000 registered attendees last year at the American Geophysical Union meeting at the Moscone center in San Francisco, and probably 22,000+ attendees this year.  The problem is, how do you accomodate all those scientists who want to present their research?  The answer (at least it has been for a couple of decades) is poster presentations.  This solution now looks like it has gotten to its obvious overwhelming stage -- thousands of posters every day in a cavernous poster hall.  My poster was number 2518, the image below is about 1/5 of the poster hall. 

The American Geophysical Union meeting in San Francisco is an annual event that I have been attending since 1974.  My first meeting was at the old Jack Tar hotel on Van Ness in 1974.  From there it spread to the Holiday Inn on Van Ness, then to the Civic Center Auditorium, and since about 15 years ago it has been at the Moscone Center. With an attendance of over 22,000 scientists this year, it is one of the largest meetings of its kind in the world. 

If you live in California and conversation drifts to earthquakes, the “BIG ONE” always surfaces.

 ‘Hey Steve, when’s the next BIG ONE coming?’

For out-of-towners, a BIG ONE refers to a ~M8 earthquake on the San Andreas Fault. The last BIG ONE was the 1906 San Francisco earthquake. Everyone knows that. The BIG ONE before that was the 1857 Ft. Tejon earthquake in the southern part of the State. Virtually nobody knows that. No surprise, in 1857 Los Angeles was a dusty backwater, home to about 4,000 townsfolk.

Spatial probability contours can be seen by using the Earthquake Viewer tool under the tools tab.  In previous blogs, I have examined the change in spatial probability contours as they evolve over time.  Here I summarize the changes over just a few weeks from 9/29/2012 to 11/23/2012.  The changes are subtle but nevertheless visible. 

On November 10, 4 days ago, a M6.8 earthquake struck Myanmar (Burma).  A friend of mine currently living in Bangkok happened to be in Mandalay and felt it strongly.  It is interesting to compare the changes in forecast contours for this region after only 4 days to the contours from Guatemala as described in the previous posting.

For the Myanmar (Burma) area, the epicenter of the quake is shown by the orange arrow.  Clear changes in contours can already be seen in the region after only 4 days (red boxes).  Recall that the contours are for M>6.5 earthquakes over the next year.

As summarized below, the Guatemala earthquake of 11/7/2012 was a M7.4 event in which several tens of persons perished, with more injured.  It was followed several days later by a M6.5 aftershock.  Below we show a comparison of forecast contours for this event, comparing the pre-mainshock contours on 11/7/2012 with those from today, 11/14/2012. 

Rocks from space.  Most of us have stepped out into the backyard and looked up at the night sky to witness a wonderful, but brief, streak of light from a falling star. Hardly star size, those streaks originate from space bits as big as grains of sand. Larger things happen however. About once per year, a Volkswagen-size rock crosses Earth’s path. These zip from horizon to horizon, burning bright for 10 or 20 seconds --- long enough maybe, for someone with quick hand on a camcorder to catch the show for appearance on the evening news.