QuakeScout
Magnitude7.7

Reviewed by USGSChile12y ago

M7.7 earthquake 53 km SW of Iquique, Chile

Thursday, April 3, 2014, 02:43:13 UTC · 20.571°S, 70.493°W

A magnitude 7.7 earthquake struck 53 km SW of Iquique, Chile on Thursday, April 3, 2014, 02:43:13 UTC, at a depth of 22.4 km (shallow). USGS received 177 “Did You Feel It?” reports, with a maximum reported intensity of VIII (severe). The USGS PAGER alert is yellow: some casualties and damage are possible. It is the strongest earthquake within 300 km since an M8.2 on April 1, 2014.

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
7.7
Major · mww
Depth
22 km
Shallow
Felt reports
177
Max intensity VIII
Est. shaking
IX
Violent (ShakeMap)
PAGER alert
Yellow
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

5.4 megatons of TNT

That is about 355 times the Hiroshima bomb. It released about 11,220 times the energy of a magnitude 5.0.

Tectonic setting

87 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

22 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
Iquique, Tarapacá, ChileVIII · Severe7957 km
Arica, Tarapacá, ChileVIII · Severe24232 km
Calama, Antofagasta, ChileVI · Strong20265 km
Antofagasta, Antofagasta, ChileV · Moderate12341 km
Tocopilla, Antofagasta, ChileVIII · Severe9172 km
Tacna, Tacna, PeruVI · Strong7284 km
Arequipa, Arequipa, PeruIII · Weak6476 km
Ilo, Moquegua, PeruV · Moderate4337 km
Moquegua, Moquegua, PeruV · Moderate4377 km
Copiapó, Atacama, ChileII · Weak3752 km
La Paz, La Paz, BoliviaIV · Light2514 km
Pacocha, Moquegua, PeruIII · Weak2343 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 268 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.4 on April 3, 2014. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M5M6M7M81h6h1d3d7d14d30dMainshock M7.7
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 4.5101 km ENE of Iquique, Chile12y ago · 148 km NE of this epicenter
  2. 4.8106 km WNW of Iquique, Chile12y ago · 93 km NW of this epicenter
  3. 3.881 km NNE of Iquique, Chile12y ago · 131 km NE of this epicenter
  4. 4.3115 km WNW of Iquique, Chile12y ago · 109 km NW of this epicenter
  5. 4.488 km WNW of Iquique, Chile12y ago · 89 km NW of this epicenter
  6. 4.289 km WNW of Iquique, Chile12y ago · 91 km NW of this epicenter
  7. 4.3105 km WNW of Iquique, Chile12y ago · 104 km NW of this epicenter
  8. 4.291 km WNW of Iquique, Chile12y ago · 84 km NW of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 684 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 8.293 km NW of Iquique, ChileApril 1, 2014 · 111 km N of this epicenter
  2. 7.8102 km ENE of Iquique, ChileJune 13, 2005 · 150 km NE of this epicenter
  3. 7.736 km ESE of Tocopilla, ChileNovember 14, 2007 · 197 km S of this epicenter
  4. 7.3136 km WSW of Challapata, BoliviaJune 6, 1915 · 299 km NE of this epicenter
  5. 7.334 km NE of Tocopilla, ChileDecember 21, 1967 · 156 km S of this epicenter
  6. 7.334 km S of Iquique, ChileFebruary 23, 1933 · 32 km E of this epicenter
  7. 7.2Near the coast of Tarapaca, ChileOctober 4, 1940 · 66 km N of this epicenter
  8. 7.268 km SSE of Arica, ChileAugust 8, 1987 · 180 km N of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 54 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 28,116 recorded deaths. The most severe:

  1. 1868M8.5

    Arica

    13 Aug 1868 · 225 km away · intensity XI

    25,000 deaths$300 million damagetsunami

  2. 1877M8.3

    Off North Coast

    10 May 1877 · 103 km away · intensity XI

    2,385 deaths$2 million damagetsunami

  3. 1833M7.7

    Peru: Tacna; Chile: Arica

    18 Sep 1833 · 264 km away · intensity VIII

    700 deathsSevere damage ($5–24M)tsunami

  4. 2005M7.7

    Tarapaca

    13 Jun 2005 · 150 km away

    11 deaths$5 million damage

  5. 2014M8.2

    Northern: Iquique, Alto Hospicio

    1 Apr 2014 · 111 km away · intensity VIII

    7 deaths$100 million damagetsunami

  6. 1987M6.9

    Arica, Iquique

    8 Aug 1987 · 180 km away · intensity VII

    5 deaths$1 million damage

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

Nearby trackers

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