M4.1 earthquake 45 km SSW of Islay (Matarani), Peru

Wednesday, July 25, 2001, 09:29:01 UTC · 17.366°S, 72.298°W

A magnitude 4.1 earthquake struck 45 km SSW of Islay (Matarani), Peru on Wednesday, July 25, 2001, 09:29:01 UTC, at a depth of 33.0 km (shallow).

Magnitude: 4.1; Light · mb
Depth: 33 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: —; No 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

21 tons of TNT

That is about 1/707 of the Hiroshima bomb. A magnitude 5.0 releases about 22 times more energy.

Tectonic setting

106 km

from the nearest mapped plate boundary, between the Nazca and Altiplano plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: shallow

33 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

No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.

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 5 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.4 on July 27, 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 294 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 41 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 26,588 recorded deaths. The most severe:

1868M8.5
Arica
13 Aug 1868 · 194 km away · intensity XI
25,000 deaths$300 million damagetsunami
1833M7.7
Peru: Tacna; Chile: Arica
18 Sep 1833 · 168 km away · intensity VIII
700 deathsSevere damage ($5–24M)tsunami
1784M8.0
Arequipa,Camana,Moquegua,Tambo
13 May 1784 · 101 km away · intensity X
383 deathsSevere damage ($5–24M)tsunami
1821
Camana, Ocona, Caraveli
10 Jul 1821 · 157 km away · intensity VIII
162 deathsSevere damage ($5–24M)
2001M8.4
Arequipa, Moquegua, Tacna, Ayacucho
23 Jun 2001 · 188 km away · intensity VIII
103 deaths$200 million damagetsunami
1991M4.7
Maca, Chivay, Yanque
23 Jul 1991 · 203 km away · intensity V
92 deathsModerate damage ($1–5M)

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

Nearby trackers