# Mild earthquake in California

Discussion in 'Earth Science' started by timojin, Sep 28, 2016.

1. ### timojinValued Senior Member

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3,252
SALTON CITY, Calif., Sept. 27 (UPI) -- Almost 200 earthquakes were recorded in Southern California's Salton Sea in roughly a 24-hour period, geologists said Tuesday.
Most of the earthquakes were small but three had a magnitude of 4.0 or greater and nine of at least 3.0, the USGS said.

Seismic activity near the Salton Sea is not uncommon, since the 350-square mile body of water is located near numerous fault lines, including the notorious San Andreas.

Scientists say earthquakes that occur near fault lines increase the chance that a larger quake will follow.

The Salton Sea is located about 160 miles southeast of Los Angeles and 125 miles northeast of San Diego.

http://www.upi.com/Top_News/US/2016...ar-SoCals-Salton-Sea-USGS-says/4621474999094/

3. ### rpennerFully WiredRegistered Senior Member

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4,833
http://earthquake.usgs.gov/earthquakes/map/

Code:
time                     latitude   longitude    depth mag
2016-09-27T00:09:04.790Z 33.2995    -115.7003333 5.46  2.57
2016-09-27T01:56:22.940Z 33.2955    -115.7143333 2.9   2.52
2016-09-27T03:06:14.250Z 33.2971667 -115.716     2.99  3.33
2016-09-27T03:23:58.150Z 33.2998333 -115.7123333 4.84  4.33
2016-09-27T03:25:05.920Z 33.2856667 -115.713     2.8   3.3
2016-09-27T03:28:38.410Z 33.2876667 -115.7268333 2.93  2.6
2016-09-27T03:29:10.660Z 33.2905    -115.7181667 2.54  2.76
2016-09-27T03:29:32.130Z 33.2915    -115.7143333 2.45  2.99
2016-09-27T03:36:15.240Z 33.3058333 -115.701     2.52  4.13
2016-09-27T03:39:40.620Z 33.3091667 -115.6933333 2.54  3.39
2016-09-27T03:46:30.410Z 33.308     -115.6973333 3.1   3.46
2016-09-27T04:39:22.390Z 33.29      -115.7181667 6.79  2.54
2016-09-27T04:43:48.930Z 33.2951667 -115.7148333 5.32  2.6
2016-09-27T04:43:51.280Z 33.287     -115.719     1.2   2.99
2016-09-27T05:52:50.520Z 33.2906667 -115.711     6.74  3.18
2016-09-27T06:42:21.510Z 33.2943333 -115.7078333 5.3   2.5
2016-09-27T09:46:31.370Z 33.2978333 -115.7136667 3.02  2.68
2016-09-27T14:01:38.680Z 33.3116667 -115.6898333 2.95  2.58


5. ### timojinValued Senior Member

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3,252
Is the depth in kilometers? the quake is in the lake , What is the elevation of the lake ?

7. ### YazataValued Senior Member

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4,883
California experiences small earthquakes every day. We get used to it.

The USGS has recorded more than a thousand small earthquakes in California, Nevada and northern Baja in the last week. That isn't extraordinary, every week is like that. Many of them were so small as to be imperceptible to anything but instruments. I think that the 4's near the Salton Sea were the biggest of them. That's big enough to cause very noticeable shaking in soft soils like those around the Salton sea. Probably not much damage though.

Earthquakes are relatively common around the Salton sea. The depression where that man-made salt lake lies is experiencing similar tectonic stresses to those ripping Baja California away from Mexico. The stresses doing that tearing extend north of the Gulf, into the Imperial Valley area and into the very complex transverse mountain ranges east and north of LA that kind of lock everything up as larger stresses build. (Lots of danger of large earthquakes there.) Notice the line of earthquakes extending south from the Imperial valley in a line through the Mexicali area to the northern end of the Gulf of California.

https://www.iris.edu/hq/programs/education_and_outreach/animations/27

Last edited: Sep 28, 2016
8. ### Magical RealistValued Senior Member

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11,625
It's the big one Yazata. Better inflate that raft. California is sliding into the Pacific.

9. ### YazataValued Senior Member

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4,883
I see that there was a 3.2 at 3:26 PM (UTC)/ 8:26 AM PDT on Wednesday Sept 28 in the hills east of San Jose, not tremendously far from where I live. I didn't feel anything.

http://earthquake.usgs.gov/earthquakes/eventpage/nc72703906#executive

The USGS intensity map, based on individuals' reports of felt intensity where they were located, indicates that it was only lightly felt here and there.

http://earthquake.usgs.gov/earthquakes/eventpage/nc72703906#dyfi

Here's some background on this citizen-science project:

http://earthquake.usgs.gov/data/dyfi/background.php

I just submitted my eyewitness report (oh, no!) that I didn't feel anything. (They want people to report even if they didn't feel anything, to help define the boundaries of where it was felt.) My zip code appeared in white (not felt) on the intensity map soon after I submitted my online form.

Last edited: Sep 29, 2016
10. ### YazataValued Senior Member

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4,883
I see where the California Office of Emergency Services has issued an earthquake "advisory" for "southern California" (not exactly a small area) due to what it calls a recent "swarm" of small earthquakes. The advisory covers Ventura, Los Angeles, Kern, San Bernardino, Riverside, Orange, Imperial and San Diego counties.

Of course, earthquakes are a constant danger all over California, not least Southern California. People should always be prepared. But I'm not convinced that the recent Salton Sea earthquakes mean a larger one is coming. I suspect that the government just wants to look like it's on top of the situation.

There do seem to have been a lot of earthquakes recently in an arc from around San Bernardino, east of Riverside and west of Palm Springs (the San Gorgonio mountains area) down towards the Salton Sea. But there are often lots of small earthquakes there.

Last edited: Oct 1, 2016
11. ### YazataValued Senior Member

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4,883
The biggest concentration of moderate earthquakes in the last 24 hours appears to have been in the South Pacific, a couple of 5's near Tonga and another 5 near Fiji. A 5 nearby will definitely get your attention, but it's too weak to cause a tsunami or a very much damage.