July 6, 2019 Earthquake: Ridgecrest, California, United States

Ref #1053:

Tectonic Summary

The July 6th, 2019, 03:19 UTC (July 5th 20:19 locally) Mw 7.1 earthquake in eastern California, southwest of Searles Valley, occurred as the result of shallow strike slip faulting in the crust of the North America plate. Focal mechanism solutions for the earthquake indicate rupture occurred on a steeply dipping fault as the result of either right lateral slip on a plane striking NW-SE, or as left lateral slip on a plane striking SW-NE. At the location of this earthquake, approximately 150 km northeast of San Andreas Fault - the major plate boundary in the region - the Pacific plate moves to the northwest with respect to the North America plate at a rate of approximately 48 mm/yr. The location of the earthquake falls within the Eastern California shear zone, a region of distributed faulting associated with motion across the Pacific:North America plate boundary, and an area of high seismic hazard. More detailed studies will be required to precisely identify the causative fault associated with this event, though seismic activity over the past 2 days has been occurring on two conjugate fault structures in the Airport Lake Fault Zone.

This earthquake occurs approximately 34 hours after and 11 km northwest of a M 6.4 event in the same region, on July 4th, 2019, at 17:33 UTC. The July 4th event was preceded by a short series of small foreshocks (including a M4.0 earthquake 30 minutes prior), and was followed by a robust sequence of aftershocks, including almost 250 M 2.5+ earthquakes (up until the M 7.1 event). Those events aligned with both nodal planes (NE-SW and NW-SE) of the focal mechanism solution of the M 6.4 event, which was very similar in faulting style to today's M 7.1 earthquake. The sequence includes two other M5+ earthquakes, one of which occurred 20 seconds before the M 7.1 event. The M 7.1 earthquake occurred at the NW extension of the prior sequence.

Over the past 40 years, prior to the July 4th event, 8 other M5+ earthquakes have occurred within 50 km of the July 6th, 2019 earthquake. The largest of these was a M 5.8 event on September 20, 1995, just 3 km to the west of today's event, which was felt strongly in the China Lake-Ridgecrest area, and more broadly from Los Angeles to Las Vegas.

Ref #12461:

No fatalities or major injuries reported after Friday night's 7.1-magnitude earthquake, which jolted an area from Sacramento to Mexico and prompted the evacuation of [...] Naval Air Weapons Station China Lake in the Mojave Desert

The light damage was largely due to the remoteness of the area where the earthquake occurred[...]In Trona, a town of about 2000 people[...]fire officials said up to 50 structures were damaged.

Ref #12522:

Out of 193 mobile homes in three mobile home parks north of Ridgecrest, eight mobile homes collapsed[...]there are damaged structures in Trona

14 structural fire responses

Ref #12524:

officials assessed all buildings, utilities and facilities [at China Lake naval base] - 3598 structures in all - for 13 days after the earthquakes [incl. 4 July event] and found damage totaled $5.2 billion.

Ref #12770:

The Kern County Fire Department estimates losses of almost $2.4 million [to schools]

Ref #12545:

[...]total of $24,323,186 in eligible earthquake-related damages to public property and infrastructure[...]verified 287 homes with damages, of which 101 homes showed either major damage or were destroyed.[...]a total of 52 businesses, 17 private non profits experience some type of damage[...]The earthquake's epicenter was in China Lake Naval Air Weapons Base and has resulted in over $5 billion in damage.

Ref #1250:

USD 200 million total damage

Ref#13727:

USD 150 million in economic loss