20 June 2009

Earthquake News

Approximately 5:30 this morning a 4.4 magnitude earthquake hit the central coast of California. It probably occurred on the Sur-Nacimiento fault. I was awake but still in bed. I felt like I was waiting for something, then the earthquake hit and I thought oh that's what I was waiting for and I went back to sleep. Since then there has been 32 aftershocks and the largest was 3.3 magnitude.
The Sur-Nacimiento fault is the west side boundary of the Salinian Block (number 9 in pink) and connects with Rinconada fault. The S-N fault is complex and does not equate to a straight line like how it is shown on the above maps. It is more like a staircase, and you can see evidence of this in seismology map above with the blue aftershocks making an east-west line. On a local map you can see that the epicenter is probably just west of the town Adelaida near Lime Mountain. Perhaps the earthquake was on the locally known steep (vertical) fault called Las Tablas fault, which is included in the Sur-Nacimiento fault complex.

At any rate the earthquake had gentle undulating waves punctuated with a strong compression wave. Silas woke up and looked at me but went back to sleep too.

1 comment:

  1. The earthquake thing...a little freaky. Fires, too. In MN all we worry about is tornadoes, really. They have been bad in the past - the tornadoes (not so much this year, as we haven't gotten much rain, which is also bad). I remember the horrible fires in San Diego almost 2 yrs ago...maybe since the area is still charred we won't have to worry about it for a couple more years? Do they have earthquakes in San Diego? Anyway - I guess I haven't mentioned it (directly) on the blog yet, but I'm moving there soon, so I've started to become more curious about the weather in CA. ;)


Thanks for sharing!