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01-04-2015, 12:15 PM
Hi Tony and all,
I thought it best to restart your thread. Your first and last posts are below. This is pretty interesting; you may want to mention this to Jim Boles; I may or may not forward this (I'll "cc" you if I do). Brian, if you feel like it, put Tony's oil seep and these quakes on a map. I'll go ahead and put the quake into the SCEC Community fault model and will post in a bit.
The focal mechanism of the M4.2 is a bit odd:
It is a thrust/reverse mechanism, but the P axis is in the northwest, which means NW-SE shortening. You expect N-S shortening near a NW-SE right-lateral fault (the San Andreas). There are know to be thrust faults that strike parallel to the San Andreas at these latitudes: the P axis would be for NNE-SSW shortening for a quake like that.
Parallel-striking strike-slip and thrust faults are examples of what is known as slip partitioning. This quake strikes at high angle to San Andreas so is something different.
A nearby M3.1 on Dec 31 gas the same focal mechanism as the 4.2
Chris
http://earthquake.usgs.gov/earthquakes/e...scientific
Hi,
For what it's worth, I'm always out hiking the canyons here in Santa Clarita. I have never seen water accumulate absent precipitation. When it does rain, and there is pooling, flow, etc., the duration is in accord with the usual factors of temperature, etc.
In any event, it will be interesting to see what the respective thoughts are on this.
Tony
Just as a follow up, there have been three quakes about seven miles due north of these observations; a 3.1 on December 30, 2014, a 3.1 on January 3, 2015, followed by a 4.5 about 15 minutes later. It appears that the quakes occurred on a fault running immediately adjacent to the San Andreas.
Tony
I thought it best to restart your thread. Your first and last posts are below. This is pretty interesting; you may want to mention this to Jim Boles; I may or may not forward this (I'll "cc" you if I do). Brian, if you feel like it, put Tony's oil seep and these quakes on a map. I'll go ahead and put the quake into the SCEC Community fault model and will post in a bit.
The focal mechanism of the M4.2 is a bit odd:
It is a thrust/reverse mechanism, but the P axis is in the northwest, which means NW-SE shortening. You expect N-S shortening near a NW-SE right-lateral fault (the San Andreas). There are know to be thrust faults that strike parallel to the San Andreas at these latitudes: the P axis would be for NNE-SSW shortening for a quake like that.
Parallel-striking strike-slip and thrust faults are examples of what is known as slip partitioning. This quake strikes at high angle to San Andreas so is something different.
A nearby M3.1 on Dec 31 gas the same focal mechanism as the 4.2
Chris
http://earthquake.usgs.gov/earthquakes/e...scientific
Hi,
For what it's worth, I'm always out hiking the canyons here in Santa Clarita. I have never seen water accumulate absent precipitation. When it does rain, and there is pooling, flow, etc., the duration is in accord with the usual factors of temperature, etc.
In any event, it will be interesting to see what the respective thoughts are on this.
Tony
Just as a follow up, there have been three quakes about seven miles due north of these observations; a 3.1 on December 30, 2014, a 3.1 on January 3, 2015, followed by a 4.5 about 15 minutes later. It appears that the quakes occurred on a fault running immediately adjacent to the San Andreas.
Tony