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Location:
24km SSE of Trona, CA
Period:
5 Jul 2019 12:21:47 - 18 Jul 2019 11:52:54 (12 days 23 hours 31 minutes)
Volcanoes in 100km radius:
None
Earthquakes:
643
113 swarms found nearby.
2000
S20000126.1(29.0km)
25 Jan
1 day 8 hours
31 earthquakes
S20000229.1(21.7km)
28 Feb
9 days 21 hours
154 earthquakes
S20000329.1(16.1km)
28 Mar
9 days 13 hours
115 earthquakes
S20000911.1(17.3km)
10 Sep
9 days 14 hours
140 earthquakes
S20000921.1(18.2km)
20 Sep
15 days 13 hours
274 earthquakes
2001
S20010408.1(15.5km)
7 Apr
1 day 16 hours
29 earthquakes
S20010423.1(18.7km)
23 Apr
8 days 21 hours
256 earthquakes
S20010610.1(17.1km)
9 Jun
4 days 3 hours
51 earthquakes
S20010714.1(18.6km)
14 Jul
67 days 13 hours
5060 earthquakes
2002
S20020907.1(18.4km)
6 Sep
2 days 1 hours
31 earthquakes
2004
S20040224.2(13.7km)
24 Feb
1 day 20 hours
36 earthquakes
S20040629.1(13.5km)
28 Jun
3 days 22 hours
108 earthquakes
S20040712.1(17.2km)
11 Jul
17 days 11 hours
158 earthquakes
S20040807.1(16.6km)
6 Aug
8 days 18 hours
101 earthquakes
S20040915.1(13.8km)
14 Sep
8 days 20 hours
86 earthquakes
S20040925.1(19.4km)
24 Sep
4 days 9 hours
57 earthquakes
S20041202.1(14.7km)
1 Dec
2 days 18 hours
36 earthquakes
2005
S20050926.1(12.7km)
25 Sep
1 day 9 hours
41 earthquakes
2006
S20060104.1(15.3km)
3 Jan
2 days 16 hours
37 earthquakes
S20060324.1(12.1km)
23 Mar
4 days 11 hours
67 earthquakes
S20060713.1(17.2km)
12 Jul
6 days 5 hours
67 earthquakes
S20060813.1(25.7km)
12 Aug
8 days 13 hours
97 earthquakes
S20060824.1(13.2km)
23 Aug
8 days 12 hours
89 earthquakes
S20061127.1(14.2km)
27 Nov
7 days 11 hours
109 earthquakes
2009
31 Dec
1 day 18 hours
54 earthquakes
2010
S20100114.1(14.9km)
13 Jan
11 days 8 hours
443 earthquakes
S20100302.1(20.6km)
1 Mar
5 days 11 hours
44 earthquakes
S20100424.1(14.6km)
23 Apr
2 days 15 hours
41 earthquakes
18 Oct
2 days 0 hours
40 earthquakes
23 Oct
7 days 5 hours
92 earthquakes
S20101125.1(13.0km)
25 Nov
1 day 13 hours
36 earthquakes
S20101202.1(11.0km)
1 Dec
1 day 12 hours
30 earthquakes
2011
28 Jul
2 days 6 hours
40 earthquakes
2012
S20120106.1(19.3km)
6 Jan
2 days 18 hours
48 earthquakes
15 Oct
5 days 7 hours
74 earthquakes
S20121024.1(15.6km)
23 Oct
6 days 5 hours
80 earthquakes
S20121127.1(21.7km)
26 Nov
24 days 0 hours
802 earthquakes
2013
S20130321.1(13.6km)
20 Mar
4 days 15 hours
80 earthquakes
S20130406.1(12.8km)
5 Apr
3 days 20 hours
59 earthquakes
S20130611.1(18.3km)
10 Jun
3 days 18 hours
43 earthquakes
11 Aug
2 days 13 hours
64 earthquakes
2014
S20140321.1(11.5km)
20 Mar
1 day 19 hours
35 earthquakes
2015
S20150217.1(22.1km)
16 Feb
11 days 1 hours
139 earthquakes
S20150602.1(12.8km)
1 Jun
1 day 6 hours
36 earthquakes
S20150608.1(24.1km)
8 Jun
1 day 13 hours
31 earthquakes
2016
S20160331.1(15.4km)
30 Mar
1 day 14 hours
27 earthquakes
S20160813.1(10.0km)
12 Aug
2 days 10 hours
46 earthquakes
S20160821.1(12.8km)
20 Aug
2 days 0 hours
37 earthquakes
S20161206.1(12.3km)
5 Dec
6 days 9 hours
75 earthquakes
2017
S20170521.1(13.0km)
20 May
1 day 16 hours
35 earthquakes
S20170608.1(14.4km)
8 Jun
3 days 3 hours
52 earthquakes
2018
S20181130.1(10.8km)
29 Nov
2 days 17 hours
51 earthquakes
2019
S20190318.1(14.2km)
17 Mar
4 days 6 hours
102 earthquakes
S20190511.1(17.8km)
10 May
5 days 12 hours
90 earthquakes
5 Jul
7 days 1 hours
190 earthquakes
S20190712.1(20.4km)
11 Jul
16 hours
29 earthquakes
S20190721.1(22.0km)
20 Jul
9 days 5 hours
474 earthquakes
S20190803.1(12.1km)
2 Aug
2 days 8 hours
77 earthquakes
4 Aug
41 days 17 hours
1154 earthquakes
14 Aug
2 days 19 hours
120 earthquakes
19 Aug
1 day 7 hours
38 earthquakes
20 Aug
3 days 6 hours
383 earthquakes
S20190825.1(17.4km)
24 Aug
3 days 7 hours
165 earthquakes
2 Sep
1 day 14 hours
76 earthquakes
4 Sep
3 days 10 hours
79 earthquakes
S20190910.1(24.9km)
10 Sep
3 days 21 hours
145 earthquakes
S20190915.1(11.8km)
14 Sep
25 days 14 hours
387 earthquakes
17 Sep
14 days 12 hours
471 earthquakes
S20191005.1(16.1km)
5 Oct
3 days 16 hours
147 earthquakes
6 Oct
1 day 16 hours
48 earthquakes
10 Oct
4 days 18 hours
165 earthquakes
17 Oct
21 days 21 hours
614 earthquakes
7 Nov
9 days 8 hours
234 earthquakes
S20191116.2(17.2km)
16 Nov
3 days 4 hours
90 earthquakes
18 Nov
10 days 3 hours
223 earthquakes
S20191201.1(21.4km)
30 Nov
27 days 2 hours
353 earthquakes
10 Dec
2 days 14 hours
78 earthquakes
14 Dec
1 day 17 hours
43 earthquakes
2020
S20200101.1(12.8km)
1 Jan
7 days 0 hours
130 earthquakes
S20200107.2(17.0km)
7 Jan
11 days 11 hours
163 earthquakes
8 Jan
23 hours
27 earthquakes
11 Feb
230 days 17 hours
4310 earthquakes
18 Feb
3 days 4 hours
87 earthquakes
27 Feb
7 days 2 hours
113 earthquakes
S20200307.1(23.3km)
6 Mar
10 days 22 hours
145 earthquakes
8 Mar
12 days 22 hours
242 earthquakes
S20200322.1(28.0km)
21 Mar
10 days 13 hours
140 earthquakes
S20200324.1(22.4km)
23 Mar
6 days 13 hours
82 earthquakes
2 Apr
3 days 6 hours
67 earthquakes
22 Apr
2 days 13 hours
45 earthquakes
S20200509.2(20.0km)
8 May
3 days 23 hours
49 earthquakes
20 May
4 days 3 hours
97 earthquakes
26 May
3 days 23 hours
82 earthquakes
12 Jun
15 days 8 hours
334 earthquakes
S20200708.3(13.2km)
7 Jul
13 days 9 hours
239 earthquakes
21 Aug
4 days 6 hours
66 earthquakes
26 Aug
25 days 23 hours
356 earthquakes
2 Oct
25 days 20 hours
320 earthquakes
9 Oct
3 days 6 hours
59 earthquakes
12 Nov
13 days 17 hours
181 earthquakes
2021
S20210213.1(25.3km)
12 Feb
1 day 17 hours
29 earthquakes
S20210404.1(16.3km)
3 Apr
11 days 13 hours
124 earthquakes
S20210616.1(17.4km)
15 Jun
4 days 20 hours
83 earthquakes
19 Aug
19 days 14 hours
212 earthquakes
S20211029.2(19.7km)
29 Oct
3 days 9 hours
48 earthquakes
S20211219.1(22.9km)
18 Dec
13 days 0 hours
143 earthquakes
2022
25 Jan
2 days 8 hours
59 earthquakes
S20220204.1(13.7km)
3 Feb
3 days 0 hours
45 earthquakes
7 Jun
1 day 20 hours
34 earthquakes
S20220715.1(29.3km)
14 Jul
4 days 3 hours
55 earthquakes
2023
S20230503.1(12.8km)
2 May
1 day 6 hours
32 earthquakes
2024
S20240416.2(25.2km)
15 Apr
2 days 15 hours
51 earthquakes
10 Aug
5 days 16 hours
78 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm S20190706.2: Analysis of Activity Near Trona, California

Seismic swarm S20190706.2 occurred in a tectonically active region of southern California, centered 24 km south-southeast of Trona in San Bernardino County. This area lies within the Mojave Desert portion of the Eastern California Shear Zone, where northwest-trending right-lateral strike-slip faults accommodate a significant fraction of Pacific-North America plate motion. The local geology features Precambrian basement rocks overlain by Quaternary alluvium and lacustrine deposits associated with ancient Searles Lake. The Garlock Fault, a major left-lateral structure, lies immediately north, while the swarm epicenters align with secondary faults linked to the Little Lake and Airport Lake fault zones.

The swarm initiated at 12:21 UTC on 5 July 2019 and concluded at 11:52 UTC on 18 July 2019, spanning 311 hours and 31 minutes. During this interval, 643 earthquakes were recorded. Analysis of the first 100 events reveals predominantly shallow foci between 0 and 13 km depth, with the majority clustered between 2 and 8 km. Magnitudes ranged from 0.7 to 4.4, including several events above magnitude 3.0 that occurred within the first 24 hours. Notable early shocks included a magnitude 4.4 at 03:30 UTC on 6 July at 8 km depth, followed closely by magnitude 3.6 and 3.5 events. Subsequent activity showed a gradual decline in both rate and maximum magnitude, consistent with typical swarm behavior driven by fluid migration or aseismic slip rather than a single mainshock-aftershock sequence.

Historical records indicate that the Trona region has experienced recurrent swarms. Since 1 January 2000, 54 swarms have been documented in the immediate vicinity. Annual counts vary, with peaks in 2004 (7 swarms), 2010 (7 swarms), and lower activity in intervening years such as 2002, 2005, and 2018 (1 swarm each). The 2019 sequence represents the second swarm of that year, underscoring the persistent seismic productivity of the area.

This swarm unfolded within the broader context of the July 2019 Ridgecrest earthquake sequence, though its parameters are classified independently. The shallow depth distribution and rapid succession of moderate events highlight the potential for ground shaking in nearby communities, including Trona and Ridgecrest. Continued monitoring remains essential given the region's position at the intersection of multiple active fault systems.

References

  • United States Geological Survey Earthquake Catalog
  • California Geological Survey Fault Activity Map
  • Southern California Earthquake Data Center Swarm Database