M7.1 earthquake 30 km SW of Islay (Matarani), Peru

Tuesday, April 12, 1988, 23:19:55 UTC · 17.192°S, 72.305°W

A magnitude 7.1 earthquake struck 30 km SW of Islay (Matarani), Peru on Tuesday, April 12, 1988, 23:19:55 UTC, at a depth of 33.1 km (shallow). It is the strongest earthquake within 300 km since an M7.2 on October 11, 1922.

Magnitude: 7.1; Major · mw
Depth: 33 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: VII; Very strong (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

674 kilotons of TNT

That is about 45 times the Hiroshima bomb. It released about 1,413 times the energy of a magnitude 5.0.

Tectonic setting

121 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 200 km

USGS lists 13 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.2 on April 13, 1988. 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 155 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 35 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 26,391 recorded deaths. The most severe:

1868M8.5
Arica
13 Aug 1868 · 209 km away · intensity XI
25,000 deaths$300 million damagetsunami
1833M7.7
Peru: Tacna; Chile: Arica
18 Sep 1833 · 181 km away · intensity VIII
700 deathsSevere damage ($5–24M)tsunami
1784M8.0
Arequipa,Camana,Moquegua,Tambo
13 May 1784 · 84 km away · intensity X
383 deathsSevere damage ($5–24M)tsunami
1821
Camana, Ocona, Caraveli
10 Jul 1821 · 140 km away · intensity VIII
162 deathsSevere damage ($5–24M)
1960M7.8
Arequipa,Chuquibamba,Caraveli,Cotahuasi
13 Jan 1960 · 167 km away · intensity X
63 deathsSevere damage ($5–24M)tsunami
1914
Pararca,Paysa,Colta,Oyala
2 Dec 1914 · 241 km away · intensity X
34 deathsSevere damage ($5–24M)

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

Nearby trackers