M4.6 earthquake 36 km WSW of Santa Cruz, Chile

Sunday, May 30, 2010, 02:27:43 UTC · 34.795°S, 71.722°W

A magnitude 4.6 earthquake struck 36 km WSW of Santa Cruz, Chile on Sunday, May 30, 2010, 02:27:43 UTC, at a depth of 46.9 km (shallow). USGS received 120 “Did You Feel It?” reports, with a maximum reported intensity of V (moderate). It is the strongest earthquake within 300 km since an M4.6 on May 29, 2010.

Magnitude: 4.6; Light · mb
Depth: 47 km; Shallow
Felt reports: 120; Max intensity V
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

120 tons of TNT

That is about 1/126 of the Hiroshima bomb. A magnitude 5.0 releases about 4 times more energy.

Tectonic setting

149 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

47 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.

Place	Intensity	Reports	Distance
Santiago, Metropolitana, Chile	III · Weak	56	184 km
Talca, Maule, Chile	IV · Light	13	83 km
Curicó, Maule, Chile	V · Moderate	10	67 km
Rancagua, Libertador General Bernardo OʿHiggins, Chile	IV · Light	10	123 km
San Fernando, Libertador General Bernardo OʿHiggins, Chile	IV · Light	6	85 km
Rengo, Libertador General Bernardo OʿHiggins, Chile	IV · Light	3	100 km
Puente Alto, Metropolitana, Chile	III · Weak	3	175 km
Santa Cruz, Libertador General Bernardo OʿHiggins, Chile	V · Moderate	2	59 km
Buin, Metropolitana, Chile	III · Weak	2	155 km
San Vicente, Libertador General Bernardo OʿHiggins, Chile	III · Weak	2	85 km
Lampa, Metropolitana, Chile	V · Moderate	1	190 km
Melipilla, Metropolitana, Chile	IV · Light	1	139 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 50 km

USGS lists 13 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.0 on June 11, 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.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 634 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 42 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 35,721 recorded deaths. The most severe:

1939M8.3
Chillan
25 Jan 1939 · 169 km away · intensity X
30,000 deaths$920 million damagetsunami
1906M8.2
South Central
17 Aug 1906 · 201 km away · intensity XI
4,000 deaths$100 million damagetsunami
2010M8.8
Maule, Concepcion, Talcahuano
27 Feb 2010 · 182 km away · intensity IX
558 deaths$30 billion damagetsunami
1965M7.3
Central
28 Mar 1965 · 271 km away
400 deaths$125 million damage
1928M7.6
Talca, Chillan, Santiago, San Fernando
1 Dec 1928 · 34 km away · intensity IX
279 deathsSevere damage ($5–24M)tsunami
1985M8.0
Central Coast, San Antonio, Valparaiso
3 Mar 1985 · 185 km away · intensity VIII
180 deaths$1.5 billion damagetsunami

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

Nearby trackers