2019 Ridgecrest earthquakes

2019 Ridgecrest earthquakes

Ridgecrest Los Angeles Bakersfield Las Vegas Sacramento San Diego Tijuana
UTC time
	A: 2019-07-04 17:33:49
	B: 2019-07-05 11:07:53
	C: 2019-07-06 03:19:52
	D: 2020-06-04 01:32:11
ISC event
	A: 616217956
	B: 616043696
	C: 616203758
USGS-ANSS
	A: ComCat
	B: ComCat
	C: ComCat
	D: ComCat
Local date
	A: July 4, 2019 (2019-07-04)
	B: July 5, 2019 (2019-07-05)
	C: July 5, 2019 (2019-07-05)
	D: June 3, 2020 (2020-06-03)
Local time
	A: 10:33 a.m. PDT
	B: 4:08 a.m. PDT
	C: 8:19 p.m. PDT
	D: 6:32 p.m. PDT
Magnitude
	A: Mw6.4[1]
	B: Mw5.4[2]
	C: Mw7.1[3]
	D: Mw5.5[4]
Depth
	A: 10.7 km (6.6 mi)
	B: 7.0 km (4.3 mi)
	C: 8.0 km (5.0 mi)
	D: 6.8 km (4.2 mi)
Epicenter	35°45′58″N 117°36′18″W / 35.766°N 117.605°W / 35.766; -117.605
Type	Strike-slip
Areas affected	California, Nevada, Arizona
Total damage	$5.3 billion[5][6]
Max. intensity	MMI IX (Violent)
Peak acceleration	0.48 g [7]
Foreshocks	2 (≥2.5 Mw ) (including before main foreshock)
Aftershocks	4,000 ~1,200 (≥2.5 Mw ) (including after main foreshock)
Casualties	1 death, 25 injured (20 on July 4, 5 on July 5)

The 2019 Ridgecrest earthquakes (more commonly referred to in scientific literature as the 2019 Ridgecrest earthquake sequence) of July 4 and 5 occurred north and northeast of the town of Ridgecrest, California located in Kern County and west of Searles Valley (approximately 200 km [122 mi] north-northeast of Los Angeles). They included three initial main shocks of M_w magnitudes 6.4, 5.4, and 7.1,^[8] and many perceptible aftershocks, mainly within the area of the Naval Air Weapons Station China Lake. Eleven months later, a M_w  5.5 aftershock took place (the largest aftershock of the sequence) to the east of Ridgecrest. The first main shock (now deemed to be a foreshock) occurred on Thursday, July 4 at 10:33 a.m. PDT, approximately 18 km (11.2 mi) ENE of Ridgecrest, and 13 km (8.1 mi) WSW of Trona,^[9] on a previously unnoticed NE-SW trending fault where it intersects the NW-SE trending Little Lake Fault Zone.^[10] This quake was preceded by several smaller earthquakes, and was followed by more than 1,400 detected aftershocks. The M 5.4 and M 7.1 quakes struck on Friday, July 5 at 4:08 a.m. and 8:19 p.m. PDT approximately 10 km (6 miles) to the northwest. The latter, now considered the mainshock, was the most powerful earthquake to occur in the state in 20 years (after the 1999 Hector Mine earthquake).^[11] Subsequent aftershocks extended approximately 50 km (~30 miles) along the Little Lake Fault Zone.

Relatively minor damage resulted from the initial foreshock, though some building fires were reported in Ridgecrest near the epicenter. The main quake on July 5 cut power to at least 3,000 residents in Ridgecrest.^[12][11] Effects were felt across much of Southern California, parts of Arizona and Nevada,^[13] as far north as the San Francisco Bay Area and Sacramento, and as far south as Baja California, Mexico. An estimated 20 million people experienced the foreshock, and approximately 30 million people experienced the mainshock.^[14]