Magnitude7.1

Reviewed by USGSPeru13y ago

M7.1 earthquake 16 km WSW of Atiquipa, Peru

Wednesday, September 25, 2013, 16:42:43 UTC · 15.838°S, 74.511°W

A magnitude 7.1 earthquake struck 16 km WSW of Atiquipa, Peru on Wednesday, September 25, 2013, 16:42:43 UTC, at a depth of 40.0 km (shallow). USGS received 89 “Did You Feel It?” reports, with a maximum reported intensity of VIII (severe). The USGS PAGER alert is green: low likelihood of casualties and damage. It is the strongest earthquake within 300 km since an M8.4 on June 23, 2001.

Tsunami flagUSGS sets this flag for large events in oceanic regions so tsunami warning centers review them. It does not by itself mean a tsunami occurred. Check tsunami.gov and local authorities for official messages.

Magnitude
7.1
Major · mww
Depth
40 km
Shallow
Felt reports
89
Max intensity VIII
Est. shaking
VII
Very strong (ShakeMap)
PAGER alert
Green
Impact estimate
Tsunami
Flag
Check tsunami.gov

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

93 km

from the nearest mapped plate boundary, between the Nazca and Altiplano plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

40 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.

PlaceIntensityReportsDistance
San Luis, Lima Provincias, PeruIII · Weak42496 km
Lima, Lima Provincias, PeruIII · Weak20500 km
Acarí, Arequipa, PeruVIII · Severe661 km
Arequipa, Arequipa, PeruIV · Light5327 km
Santa María, Lima Provincias, PeruIII · Weak4498 km
Santiago, Ica, PeruVI · Strong1228 km
Arica, Tarapacá, ChileIV · Light1537 km
San Vicente de Cañete, Lima Provincias, PeruIV · Light1368 km
Pisco, Ica, PeruIII · Weak1301 km
Los Aquijes, Ica, PeruIII · Weak1232 km
Nuevo Imperial, Lima Provincias, PeruIII · Weak1364 km
Iquique, Tarapacá, ChileIII · Weak1672 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 populated area was estimated to feel noticeable shaking.

After the main event

Aftershocks within 200 km

USGS lists 5 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M4.6 on September 26, 2013. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 436 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 39 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 1,065 recorded deaths. The most severe:

  1. 1784M8.0

    Arequipa,Camana,Moquegua,Tambo

    13 May 1784 · 278 km away · intensity X

    383 deathsSevere damage ($5–24M)tsunami

  2. 1821

    Camana, Ocona, Caraveli

    10 Jul 1821 · 168 km away · intensity VIII

    162 deathsSevere damage ($5–24M)

  3. 1913M6.3

    Amyaraes, Abancay, Casaya, Soraya

    4 Nov 1913 · 251 km away · intensity X

    150 deathsSevere damage ($5–24M)

  4. 2001M8.4

    Arequipa, Moquegua, Tacna, Ayacucho

    23 Jun 2001 · 104 km away · intensity VIII

    103 deaths$200 million damagetsunami

  5. 1960M7.8

    Arequipa,Chuquibamba,Caraveli,Cotahuasi

    13 Jan 1960 · 189 km away · intensity X

    63 deathsSevere damage ($5–24M)tsunami

  6. 1914

    Pararca,Paysa,Colta,Oyala

    2 Dec 1914 · 157 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

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