M4.3 earthquake 4 km WSW of DuPont, Washington

Sunday, July 22, 2001, 15:13:52 UTC · 47.088°N, 122.687°W

A magnitude 4.3 earthquake struck 4 km WSW of DuPont, Washington on Sunday, July 22, 2001, 15:13:52 UTC, at a depth of 52.3 km (shallow). USGS received 740 “Did You Feel It?” reports, with a maximum reported intensity of V (moderate).

Magnitude: 4.3; Light · md
Depth: 52 km; Shallow
Felt reports: 740; Max intensity V
Est. shaking: III; Weak (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 50 km aftershock search area

In context

How big was it, and why here?

Energy released

43 tons of TNT

That is about 1/354 of the Hiroshima bomb. A magnitude 5.0 releases about 11 times more energy.

Tectonic setting

247 km

from the nearest mapped plate boundary, between the Juan de Fuca and North American plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: shallow

52 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
98501<br>0.109	III · Weak	62	55 km
98502<br>0.141	III · Weak	38	58 km
98506<br>0.168	III · Weak	28	54 km
98503<br>0.178	III · Weak	25	53 km
98387<br>0.194	III · Weak	21	56 km
98513<br>0.203	II · Weak	19	53 km
98371<br>0.208	III · Weak	18	60 km
98312<br>0.230	III · Weak	14	75 km
98512<br>0.230	III · Weak	14	60 km
98328<br>0.236	IV · Light	13	67 km
98116<br>0.236	III · Weak	13	78 km
98367<br>0.236	III · Weak	13	67 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 50 km

USGS lists 15 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.3 on July 31, 2001. 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 40 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 8 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 77 recorded deaths. The most severe:

1980M5.2
Mt St Helens
18 May 1980 · 104 km away · intensity V
61 deaths$2.0 billion damagetsunami
1949M7.0
Washington
13 Apr 1949 · 10 km away · intensity VIII
8 deaths$25 million damagetsunami
1965M6.6
Seattle
29 Apr 1965 · 45 km away · intensity VIII
7 deaths$28 million damage
2001M6.8
Olympia, Seattle, Tacoma
28 Feb 2001 · 7 km away · intensity VIII
1 death$2.0 billion damage
1993M5.6
Washington-Oregon Border
25 Mar 1993 · 228 km away · intensity VII
$28 million damage
1700M9.0
Cascadia Subduction Zone
27 Jan 1700 · 293 km away
Severe damage ($5–24M)tsunami

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

Nearby trackers