Location:

Period:

4 May 2015 02:13:15 - 7 May 2015 00:27:01 (2 days 22 hours 13 minutes)

Volcanoes in 100km radius:

Mono Lake Volcanic Field(18km), Mono-Inyo Craters(32km), Mammoth Mountain(49km)

Earthquakes:

111

21 swarms found nearby.

2001

S20010308.1(21.7km)

7 Mar

2 days 6 hours

47 earthquakes

S20010320.1(8.6km)

20 Mar

6 days 14 hours

96 earthquakes

2004

S20040918.1(3.6km)

17 Sep

67 days 17 hours

4783 earthquakes

S20041214.1(15.4km)

13 Dec

15 days 7 hours

237 earthquakes

2006

S20060505.1(20.9km)

5 May

1 day 14 hours

30 earthquakes

2008

S20080115.1(14.0km)

15 Jan

2 days 10 hours

50 earthquakes

S20080201.1(14.6km)

1 Feb

2 days 6 hours

54 earthquakes

2009

S20090831.1(21.2km)

30 Aug

2 days 4 hours

34 earthquakes

2011

S20110704.1(21.4km)

3 Jul

3 days 20 hours

49 earthquakes

2015

S20150510.1(1.5km)

9 May

2 days 3 hours

35 earthquakes

2016

S20160805.1(24.8km)

4 Aug

5 days 7 hours

205 earthquakes

S20161228.1(20.5km)

28 Dec

58 days 12 hours

4521 earthquakes

2017

S20170415.1(26.3km)

15 Apr

12 hours

83 earthquakes

S20171009.1(25.1km)

8 Oct

3 days 3 hours

371 earthquakes

S20171015.2(16.4km)

15 Oct

16 hours

26 earthquakes

S20171020.1(9.5km)

19 Oct

2 days 13 hours

33 earthquakes

2018

S20180207.1(24.9km)

7 Feb

2 days 14 hours

56 earthquakes

S20181207.1(4.8km)

7 Dec

1 day 2 hours

33 earthquakes

S20181217.1(4.9km)

17 Dec

2 days 9 hours

44 earthquakes

2020

S20200411.1(4.3km)

11 Apr

33 days 8 hours

1019 earthquakes

2021

S20210115.1(28.9km)

15 Jan

1 day 14 hours

89 earthquakes

AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm S20150505.1: Analysis of Activity Near Lee Vining, California

Seismic swarm S20150505.1 was recorded 28 km east-northeast of Lee Vining, California, beginning at 02:13 on 4 May 2015 and concluding at 00:27 on 7 May 2015. Over 70 hours and 13 minutes, the sequence produced 111 earthquakes. Analysis of the first 100 events shows predominantly low-magnitude activity, with the largest event reaching magnitude 2.6 at a depth of 6 km. Depths across the sequence ranged from 3 km to 14 km, and most events clustered between 4 km and 8 km. The initial event measured magnitude 0.8 at 10 km depth, followed by a gradual increase in frequency and occasional peaks above magnitude 2.0, including events of 2.1, 2.4, and 2.0 later in the sequence.

The Lee Vining area lies within Mono County in eastern California, at the transition between the Sierra Nevada and the Basin and Range Province. This tectonic setting features active normal faulting driven by regional extension associated with the Walker Lane belt. The region is also influenced by proximity to the Long Valley Caldera, a large volcanic system whose most recent major eruption occurred approximately 760,000 years ago. Ongoing geothermal activity and fluid movement within the crust contribute to the area's elevated seismicity. Mono Lake, located immediately north of Lee Vining, sits atop volcanic features including the Mono-Inyo Craters chain, which has produced eruptions as recently as 600 years ago.

Seismic swarms in this portion of the eastern Sierra Nevada are not uncommon. Historical records since 2000 document nine prior swarms in the immediate vicinity, occurring in 2001 (two swarms), 2004 (two), 2006 (one), 2008 (two), 2009 (one), and 2011 (one). These episodes typically consist of numerous small events without a single dominant mainshock, consistent with the characteristics observed in S20150505.1. Such activity is often attributed to a combination of tectonic strain release and hydrothermal fluid migration rather than magmatic intrusion.

The 2015 swarm aligns with long-term monitoring data from regional seismic networks, which show persistent low-level seismicity along faults east of the Sierra Nevada crest. No surface rupture or significant ground deformation was associated with the sequence. Magnitudes remained below levels that would produce felt shaking for most residents, although events near magnitude 2.0–2.6 may have been perceptible within a few kilometers of the epicentral area.

Continued surveillance of the Long Valley Caldera and surrounding fault systems remains essential given the region's dual tectonic and volcanic hazards. Future swarms will likely follow similar patterns of clustered, shallow seismicity driven by the same geological framework.

References

United States Geological Survey Earthquake Catalog
California Geological Survey Regional Fault Maps
Long Valley Caldera Monitoring Reports, USGS
SeismoSight internal swarm classification records