M7.1 earthquake in Ecuador

Thursday, August 12, 2010, 11:54:15 UTC · 1.266°S, 77.306°W

A magnitude 7.1 earthquake struck in Ecuador on Thursday, August 12, 2010, 11:54:15 UTC, at a depth of 206.7 km (intermediate). USGS received 282 “Did You Feel It?” reports, with a maximum reported intensity of VI (strong). It is the strongest earthquake within 300 km since an M7.2 on March 6, 1987.

Magnitude: 7.1; Major · mwc
Depth: 207 km; Intermediate
Felt reports: 282; Max intensity VI
Est. shaking: V; Moderate (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

138 km

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

Depth: intermediate

207 km

Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.

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.

Place	Intensity	Reports	Distance
Guayaquil, Guayas, Ecuador	V · Moderate	95	370 km
Quito, Pichincha, Ecuador	III · Weak	43	273 km
Cuenca, Azuay, Ecuador	IV · Light	34	333 km
Samborondón, Guayas, Ecuador	V · Moderate	11	349 km
Loja, Loja, Ecuador	IV · Light	10	422 km
Manta, Manabí, Ecuador	IV · Light	6	433 km
Machala, El Oro, Ecuador	IV · Light	5	422 km
Iquitos, Loreto, Peru	IV · Light	5	571 km
Bahía de Caráquez, Manabí, Ecuador	III · Weak	4	412 km
Ibarra, Imbabura, Ecuador	III · Weak	4	288 km
Santo Domingo, Pichincha, Ecuador	V · Moderate	3	312 km
Ambato, Tungurahua, Ecuador	II · Weak	3	253 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 PAGER estimate is available for this event.

After the main event

Aftershocks within 200 km

USGS lists 1 M2.5+ earthquake within 200 km in the following 30 days; the largest was M4.4 on August 14, 2010. 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.

4.4Ecuador16y ago · 8 km S of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 158 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 36 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 122,647 recorded deaths. The most severe:

1868M7.7
Guayaquil,Ibarra; Colombia: San Pablo
16 Aug 1868 · 200 km away · intensity X
70,000 deathsExtreme damage ($25M+)
1797M8.3
Riobamba, Quito, Cuzco; Peru; Colombia
4 Feb 1797 · 157 km away · intensity XI
40,000 deathsExtreme damage ($25M+)tsunami
1949M6.5
Tungurahua
5 Aug 1949 · 111 km away
6,000 deaths$8 million damage
1987M7.2
Napo Province, Quito, Tulcan
6 Mar 1987 · 159 km away
5,000 deaths$1.5 billion damage
1757M7.0
Cotopaxi,Tungurahua, Latacunga
22 Feb 1757 · 150 km away · intensity IX
1,000 deathsSevere damage ($5–24M)
1923M6.2
Ipiales
14 Dec 1923 · 243 km away · intensity IX
300 deathsModerate damage ($1–5M)

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

Nearby trackers