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back to EQ info.

found this at https://www.usgs.gov/faqs/what-does-it-mean-earthquake-occurred-a-depth-0-km-how-can-earthquake-have-a-negative-depth?qt-news_science_products=0#qt-news_science_products

First of all, the depth of an earthquake is usually the most difficult part of its location to nail down with great accuracy. Since most earthquakes are deep within the crust, an error of +/- 1 or 2 km is irrelevant; in other words, it is a small error when the depth is something like 13 km. If the earthquake depth is relatively shallow, however, it becomes more of an issue. A negative depth can sometimes be an artifact of the poor resolution for a shallow event.

For quarry blasts that are recorded by the seismic network, the depth is fixed at 0 km since we can never determine a precise depth for these, but we know they are very close to the surface.

Ok, so MOST EARTHQUAKES ARE DEEP WITHIN THE CRUST. Got that? EQs at the surface or quarry blasts are at 0 km depth (+/- 1 or 2 km)

So I’m looking at EQs from the past 24 hours and I see these: (note the depths)

M 1.7 - 20km NW of Searles Valley, CA

Time
2019-07-09 12:35:59 (UTC)
Location
35.909°N 117.534°W
Depth
-0.1 km

M 1.1 - 12km N of Ridgecrest, CA

Time
2019-07-09 12:34:04 (UTC)
Location
35.731°N 117.699°W
Depth
0.2 km

M 1.6 - 14km SSW of Searles Valley, CA

Time
2019-07-09 12:33:03 (UTC)
Location
35.648°N 117.458°W
Depth
0.3 km

1.2 - 15km ENE of Ridgecrest, CA

Time
2019-07-09 12:28:15 (UTC)
Location
35.667°N 117.520°W
Depth
0.3 km

M 1.3 - 10km E of Coso Junction, CA

Time
2019-07-09 12:17:14 (UTC)
Location
36.058°N 117.837°W
Depth
-0.2 km

M 1.5 - 19km ESE of Little Lake, CA

Time
2019-07-09 12:11:59 (UTC)
Location
35.890°N 117.706°W
Depth
0.6 km

M 1.8 - 9km NE of Boron, CA

III
DYFI?
Time
2019-07-09 12:09:33 (UTC)
Location
35.062°N 117.590°W
Depth
0.6 km

M 1.2 - 11km SW of Searles Valley, CA

Time
2019-07-09 11:49:00 (UTC)
Location
35.693°N 117.486°W
Depth
0.4 km

M 1.7 - 13km NNW of Johannesburg, CA

Time
2019-07-09 11:14:10 (UTC)
Location
35.486°N 117.666°W
Depth
0.0 km

M 0.9 - 20km S of Trona, CA

Time
2019-07-09 11:06:26 (UTC)
Location
35.585°N 117.359°W
Depth
0.3 km

M 0.9 - 20km ESE of Little Lake, CA

Time
2019-07-09 11:02:48 (UTC)
Location
35.846°N 117.712°W
Depth
-0.0 km

M 0.8 - 8km W of Searles Valley, CA

Time
2019-07-09 10:53:53 (UTC)
Location
35.767°N 117.490°W
Depth
0.2 km

M 0.8 - 21km ESE of Little Lake, CA

Time
2019-07-09 10:45:20 (UTC)
Location
35.871°N 117.688°W
Depth
0.1 km

M 3.5 - 21km E of Little Lake, CA

III
DYFI?
V
ShakeMap
Time
2019-07-09 10:21:52 (UTC)
Location
35.956°N 117.678°W
Depth
0.8 km

M 2.7 - 10km WSW of Searles Valley, CA

Time
2019-07-09 10:20:41 (UTC)
Location
35.720°N 117.499°W
Depth
0.6 km

So that’s about 2 hours worth. I got tired of copying/pasting, but enough for you to see the pattern. Notice all these shallow “quakes” are mostly in 2 areas of CA. (I found one in Alaska from a bit earlier.)

I only included those less than 1.0 km depth, but a fair number between 1-2 km also.