QuakeScout
Magnitude5.3

Reviewed by USGSChile16y ago

M5.3 earthquake 55 km W of Santa Cruz, Chile

Friday, May 21, 2010, 18:52:06 UTC · 34.640°S, 71.969°W

A magnitude 5.3 earthquake struck 55 km W of Santa Cruz, Chile on Friday, May 21, 2010, 18:52:06 UTC, at a depth of 7.3 km (shallow). USGS received 100 “Did You Feel It?” reports, with a maximum reported intensity of V (moderate). It is the strongest earthquake within 300 km since an M5.4 on May 5, 2010.

Magnitude
5.3
Moderate · mwc
Depth
7 km
Shallow
Felt reports
100
Max intensity V
Est. shaking
—
No ShakeMap
PAGER alert
None
Not issued
Tsunami
No flag
USGS feed

Outlined circle: this earthquakeDashed circle: 75 km aftershock search area

In context

How big was it, and why here?

Energy released

1 kilotons of TNT

That is about 1/11 of the Hiroshima bomb. It released about 3 times the energy of a magnitude 5.0.

Tectonic setting

121 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

7 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
Santiago, Metropolitana, ChileIII · Weak61179 km
Rancagua, Libertador General Bernardo OʿHiggins, ChileIV · Light7124 km
Viña del Mar, Valparaíso, ChileII · Weak7185 km
Talca, Maule, ChileIII · Weak491 km
Santa Cruz, Libertador General Bernardo OʿHiggins, ChileIV · Light355 km
San Vicente, Libertador General Bernardo OʿHiggins, ChileV · Moderate285 km
Graneros, Libertador General Bernardo OʿHiggins, ChileIV · Light2131 km
Rengo, Libertador General Bernardo OʿHiggins, ChileIV · Light2104 km
Puente Alto, Metropolitana, ChileIII · Weak2172 km
Curicó, Maule, ChileIV · Light176 km
Teno, Maule, ChileIV · Light178 km
Machalí, Libertador General Bernardo OʿHiggins, ChileIII · Weak1130 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 75 km

USGS lists 26 M2.5+ earthquakes within 75 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.

M3M4M51h6h1d3d7d14d30dMainshock M5.3
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 4.082 km WNW of Santa Cruz, Chile16y ago · 32 km NW of this epicenter
  2. 4.441 km W of Rauco, Chile16y ago · 31 km SE of this epicenter
  3. 4.357 km N of Constitución, Chile16y ago · 43 km SW of this epicenter
  4. 4.251 km W of Rauco, Chile16y ago · 39 km S of this epicenter
  5. 4.264 km N of Constitución, Chile16y ago · 35 km W of this epicenter
  6. 5.043 km WSW of Santa Cruz, Chile16y ago · 18 km SE of this epicenter
  7. 4.736 km WSW of Santa Cruz, Chile16y ago · 25 km SE of this epicenter
  8. 3.887 km WNW of Santa Cruz, Chile16y ago · 48 km NW of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 638 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 8.82010 Maule, Chile EarthquakeFebruary 27, 2010 · 185 km SW of this epicenter
  2. 8.2The 1906 Valparaiso, Chile EarthquakeAugust 17, 1906 · 255 km N of this epicenter
  3. 8.025 km WSW of Valparaíso, ChileMarch 3, 1985 · 168 km N of this epicenter
  4. 7.826 km WNW of San Carlos, ChileJanuary 25, 1939 · 185 km S of this epicenter
  5. 7.819 km NNE of Hacienda La Calera, ChileJuly 9, 1971 · 237 km N of this epicenter
  6. 7.730 km NNE of Constitución, ChileDecember 1, 1928 · 56 km SW of this epicenter
  7. 7.7103 km NW of Constitución, ChileJanuary 30, 1914 · 123 km W of this epicenter
  8. 7.523 km SE of Chiguayante, ChileMay 6, 1953 · 284 km S of this epicenter

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:

  1. 1939M8.3

    Chillan

    25 Jan 1939 · 181 km away · intensity X

    30,000 deaths$920 million damagetsunami

  2. 1906M8.2

    South Central

    17 Aug 1906 · 182 km away · intensity XI

    4,000 deaths$100 million damagetsunami

  3. 2010M8.8

    Maule, Concepcion, Talcahuano

    27 Feb 2010 · 185 km away · intensity IX

    558 deaths$30 billion damagetsunami

  4. 1965M7.3

    Central

    28 Mar 1965 · 259 km away

    400 deaths$125 million damage

  5. 1928M7.6

    Talca, Chillan, Santiago, San Fernando

    1 Dec 1928 · 40 km away · intensity IX

    279 deathsSevere damage ($5–24M)tsunami

  6. 1985M8.0

    Central Coast, San Antonio, Valparaiso

    3 Mar 1985 · 169 km away · intensity VIII

    180 deaths$1.5 billion damagetsunami

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

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