The May 29, 1968 earthquake

M5.1near Plush, Oregon

A magnitude 5.1 earthquake 14.9 miles deep, centred in Lake County. The 6th strongest in Oregon’s record since 1900, and the strongest within 50 miles in the catalogue, which runs from 1900. 4 aftershocks of magnitude 2.5 or more followed within 30 days.

The earthquake

Magnitude
5.1
body-wave magnitude (mb)
Depth
14.9 mi
24.0 km below the surface
Local time
Wednesday, May 29, 1968
17:35 PDT; 00:35 UTC on May 30, 1968
Epicentre
42.30°N, 119.80°W
In Lake County
In Oregon’s record
6th
strongest of 861 since 1900
Within 50 miles
5
counties; more on this date

USGS ANSS Comprehensive Earthquake Catalog, event ushis3007 (“15 km SE of Plush, Oregon”). 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.

4

Aftershocks in 30 days

5.0

Largest aftershock, Jun 3, 1968 · its page

0

On the first day

0

In the 7 days before

Aftershocks of magnitude 2.5 or more, by day after the earthquake 1: 0 2: 0 3: 0 4: 0 5: 1 6: 2 2 7: 1 8: 0 9: 0 10: 0 11: 0 12: 0 13: 0 14: 0 15: 0 16: 0 17: 0 18: 0 19: 0 20: 0 21: 0 22: 0 23: 0 24: 0 25: 0 26: 0 27: 0 28: 0 29: 0 30: 0 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.
  2. Before the modern seismic networks of the 1970s many small aftershocks went unrecorded, so early sequences read short.

Counties and cities within 50 miles

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

Counties

Earthquakes around the epicentre

345 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: 0 1974: 0 1975: 0 1976: 0 1977: 0 1978: 0 1979: 0 1980: 0 1981: 0 1982: 1 1983: 0 1984: 1 1985: 0 1986: 0 1987: 0 1988: 0 1989: 0 1990: 0 1991: 0 1992: 0 1993: 0 1994: 0 1995: 0 1996: 0 1997: 0 1998: 0 1999: 0 2000: 0 2001: 1 2002: 0 2003: 0 2004: 19 2005: 3 2006: 0 2007: 2 2008: 0 2009: 1 2010: 0 2011: 0 2012: 0 2013: 0 2014: 142 142 2015: 133 2016: 17 2017: 4 2018: 0 2019: 0 2020: 0 2021: 0 2022: 4 2023: 2 2024: 4 2025: 11 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.