Search
Menu

Explore

Hazards

Analysis

Rankings

Reference

The July 4, 2019 earthquake

M6.4Ridgecrest, California

A magnitude 6.4 earthquake 6.5 miles deep, centred in San Bernardino County. The 33rd strongest in California’s record since 1900, and the strongest within 50 miles in the catalogue, which runs from 1900. 2,163 aftershocks of magnitude 2.5 or more followed within 30 days.

Watch the sequence unfold

Magnitude 6.4 · July 4, 2019

How the ground moved

Every recorded earthquake in the sequence, in order, from the foreshocks to a month after.

About this replay
Local time (PDT)—Historical replay — logged times
Main shock—
Aftershocks—of 2,163 in 30 days
Largest so far—

The earthquake

Magnitude
6.4
moment magnitude (mw)
Depth
6.5 mi
10.5 km below the surface
Local time
Thursday, July 4, 2019
10:33 PDT; 17:33 UTC
Epicentre
35.71°N, 117.50°W
In San Bernardino County
In California’s record
33rd
strongest of 97,065 since 1900
Within 50 miles
4
counties; more on this date

USGS ANSS Comprehensive Earthquake Catalog, event ci38443183 (“Ridgecrest Earthquake Sequence”). The USGS event page carries the ShakeMap, felt reports and the official summary.

Aftershocks

Earthquakes of magnitude 2.5 or more within 20 miles of the epicentre in the 30 days after.

2,163

Aftershocks in 30 days

7.1

Largest aftershock, Jul 6, 2019 · its page

268

On the first day

1

In the 7 days before

Aftershocks of magnitude 2.5 or more, by day after the earthquake 1: 268 2: 1,100 1,100 3: 225 4: 102 5: 64 6: 52 7: 41 8: 35 9: 27 10: 21 11: 18 12: 24 13: 23 14: 17 15: 16 16: 12 17: 23 18: 4 19: 10 20: 8 21: 6 22: 18 23: 5 24: 3 25: 12 26: 11 27: 3 28: 4 29: 7 30: 4 1611162126
  1. The search radius is the surface rupture length expected for an earthquake of this magnitude (Wells and Coppersmith, 1994), at least 20 and at most 600 miles, so a great earthquake's sequence is counted along its whole fault.

Counties and cities within 50 miles

Distance from the epicentre to each county boundary (zero when inside) and to each city centre.

Counties

Cities, largest first

Earthquakes around the epicentre

2,309 earthquakes of magnitude 3 or more within 50 miles of this epicentre since 1973.

Earthquakes of magnitude 3 or more within 50 miles of the epicentre, by year 1973: 5 1974: 16 1975: 8 1976: 13 1977: 8 1978: 12 1979: 9 1980: 5 1981: 14 1982: 80 1983: 55 1984: 31 1985: 14 1986: 19 1987: 11 1988: 7 1989: 8 1990: 2 1991: 9 1992: 85 1993: 24 1994: 10 1995: 83 1996: 65 1997: 26 1998: 44 1999: 16 2000: 26 2001: 67 2002: 9 2003: 5 2004: 12 2005: 9 2006: 13 2007: 10 2008: 30 2009: 17 2010: 33 2011: 9 2012: 7 2013: 20 2014: 19 2015: 8 2016: 8 2017: 10 2018: 10 2019: 1,148 1,148 2020: 62 2021: 33 2022: 17 2023: 18 2024: 17 2025: 13 19731978198319881993199820032008201320182023

Earlier earthquakes of magnitude 5 or more within 50 miles, strongest first

USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.