M7.2 earthquake 153 km W of Big Lagoon, California

Wednesday, June 15, 2005, 02:50:54 UTC · 41.292°N, 125.953°W

A magnitude 7.2 earthquake struck 153 km W of Big Lagoon, California on Wednesday, June 15, 2005, 02:50:54 UTC, at a depth of 16.0 km (shallow). USGS received 2,901 “Did You Feel It?” reports, with a maximum reported intensity of V (moderate). It is the strongest earthquake within 300 km since an M7.2 on April 25, 1992.

Magnitude: 7.2; Major · mwc
Depth: 16 km; Shallow
Felt reports: 2,901; Max intensity V
Est. shaking: IV; Light (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

951 kilotons of TNT

That is about 63 times the Hiroshima bomb. It released about 1,995 times the energy of a magnitude 5.0.

Tectonic setting

64 km

from the nearest mapped plate boundary, between the Juan de Fuca and North American plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

16 km

Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.

Did You Feel It?

Where it was felt

Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.

Place	Intensity	Reports	Distance
95521<br>0.090	III · Weak	246	169 km
95501<br>0.090	III · Weak	240	161 km
95503<br>0.090	III · Weak	236	169 km
95531<br>0.090	IV · Light	180	172 km
95519<br>0.090	III · Weak	172	165 km
95540<br>0.095	III · Weak	96	172 km
97415<br>0.106	III · Weak	66	186 km
97526<br>0.110	III · Weak	61	250 km
97527<br>0.135	II · Weak	41	245 km
95536<br>0.137	IV · Light	40	171 km
95570<br>0.146	III · Weak	36	160 km
97470<br>0.165	III · Weak	29	301 km

I felt it — report to USGS ↗

USGS PAGER estimate

Who was exposed to shaking

USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.

After the main event

Aftershocks within 200 km

USGS lists 120 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.6 on June 17, 2005. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 240 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 15 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2 recorded deaths. The most severe:

1954M6.6
Humboldt County
21 Dec 1954 · 180 km away
1 death$2 million damage
1932M6.5
Eureka
6 Jun 1932 · 153 km away · intensity VIII
1 deathModerate damage ($1–5M)
1992M7.1
Humboldt County: Ferndale, Petrolia
25 Apr 1992 · 172 km away · intensity VIII
$75 million damagetsunami
1980M7.2
North Coast
8 Nov 1980 · 144 km away · intensity VII
$2 million damage
1991M6.2
Honeydew, Whitethorn, Petrolia
17 Aug 1991 · 179 km away · intensity VII
Moderate damage ($1–5M)
1994M5.5
Eureka, Samoa, Arcata, Blue Lake
26 Dec 1994 · 151 km away · intensity VII
$2 million damage

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers