Reviewed by USGSChile12y ago
M3.9 earthquake 61 km WSW of Iquique, Chile
Thursday, July 31, 2014, 16:55:58 UTC · 20.490°S, 70.658°W
A magnitude 3.9 earthquake struck 61 km WSW of Iquique, Chile on Thursday, July 31, 2014, 16:55:58 UTC, at a depth of 24.8 km (shallow).
- Magnitude
- 3.9
- Minor · mwr
- Depth
- 25 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
11 tons of TNT
That is about 1/1,410 of the Hiroshima bomb. A magnitude 5.0 releases about 45 times more energy.
Tectonic setting
71 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
25 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 4 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.6 on August 19, 2014. 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 696 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.293 km NW of Iquique, ChileApril 1, 2014 · 99 km N of this epicenter
- 7.8102 km ENE of Iquique, ChileJune 13, 2005 · 162 km E of this epicenter
- 7.736 km ESE of Tocopilla, ChileNovember 14, 2007 · 211 km S of this epicenter
- 7.753 km SW of Iquique, ChileApril 3, 2014 · 19 km SE of this epicenter
- 7.334 km NE of Tocopilla, ChileDecember 21, 1967 · 171 km SE of this epicenter
- 7.334 km S of Iquique, ChileFebruary 23, 1933 · 49 km E of this epicenter
- 7.2Near the coast of Tarapaca, ChileOctober 4, 1940 · 62 km NE of this epicenter
- 7.268 km SSE of Arica, ChileAugust 8, 1987 · 178 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 55 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 28,117 recorded deaths. The most severe:
- 1868M8.5
Arica
13 Aug 1868 · 213 km away · intensity XI
25,000 deaths$300 million damagetsunami
- 1877M8.3
Off North Coast
10 May 1877 · 113 km away · intensity XI
2,385 deaths$2 million damagetsunami
- 1833M7.7
Peru: Tacna; Chile: Arica
18 Sep 1833 · 252 km away · intensity VIII
700 deathsSevere damage ($5–24M)tsunami
- 2005M7.7
Tarapaca
13 Jun 2005 · 162 km away
11 deaths$5 million damage
- 2014M8.2
Northern: Iquique, Alto Hospicio
1 Apr 2014 · 99 km away · intensity VIII
7 deaths$100 million damagetsunami
- 1987M6.9
Arica, Iquique
8 Aug 1987 · 178 km away · intensity VII
5 deaths$1 million damage
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.