M7.1 earthquake 36 km SW of Monte Patria, Chile

Wednesday, October 15, 1997, 01:03:33 UTC · 30.933°S, 71.220°W

A magnitude 7.1 earthquake struck 36 km SW of Monte Patria, Chile on Wednesday, October 15, 1997, 01:03:33 UTC, at a depth of 58.0 km (shallow). It is the strongest earthquake within 300 km since an M7.4 on March 4, 1985.

Magnitude: 7.1; Major · mwc
Depth: 58 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

134 km

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

Depth: shallow

58 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 77 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.2 on November 3, 1997. 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 448 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 51 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 15,173 recorded deaths. The most severe:

1944M6.9
San Juan Province
15 Jan 1944 · 267 km away · intensity IX
10,000 deaths$100 million damage
1906M8.2
South Central
17 Aug 1906 · 241 km away · intensity XI
4,000 deaths$100 million damagetsunami
1965M7.3
Central
28 Mar 1965 · 163 km away
400 deaths$125 million damage
1920M6.7
Mendoza
17 Dec 1920 · 288 km away · intensity VIII
400 deathsSevere damage ($5–24M)
1985M8.0
Central Coast, San Antonio, Valparaiso
3 Mar 1985 · 249 km away · intensity VIII
180 deaths$1.5 billion damagetsunami
1971M7.8
Central
9 Jul 1971 · 174 km away · intensity IX
83 deaths$236 million damagetsunami

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

Nearby trackers