QuakeScout
Magnitude5.4

Reviewed by USGSChile16y ago

M5.4 earthquake 89 km SW of San Antonio, Chile

Thursday, July 15, 2010, 00:36:02 UTC · 34.153°S, 72.303°W

A magnitude 5.4 earthquake struck 89 km SW of San Antonio, Chile on Thursday, July 15, 2010, 00:36:02 UTC, at a depth of 8.8 km (shallow). USGS received 74 “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
5.4
Moderate · mwc
Depth
9 km
Shallow
Felt reports
74
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

2 kilotons of TNT

That is about 1/8 of the Hiroshima bomb. It released about 4 times the energy of a magnitude 5.0.

Tectonic setting

68 km

from the nearest mapped plate boundary, between the Nazca and South American plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

9 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 · Weak43172 km
Talca, Maule, ChileIV · Light4152 km
Viña del Mar, Valparaíso, ChileIII · Weak4145 km
Santa Cruz, Libertador General Bernardo OʿHiggins, ChileIV · Light3101 km
Quilpué, Valparaíso, ChileIII · Weak3144 km
San Antonio, Valparaíso, ChileV · Moderate289 km
Rancagua, Libertador General Bernardo OʿHiggins, ChileV · Moderate2144 km
Valparaíso, Valparaíso, ChileIV · Light2138 km
Curicó, Maule, ChileIV · Light2134 km
Machalí, Libertador General Bernardo OʿHiggins, ChileIV · Light1150 km
Rengo, Libertador General Bernardo OʿHiggins, ChileIV · Light1135 km
San Vicente, Libertador General Bernardo OʿHiggins, ChileIV · Light1117 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 6 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.2 on July 24, 2010. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M51h6h1d3d7d14d30dMainshock M5.4
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 4.371 km NNE of Constitución, Chile16y ago · 64 km S of this epicenter
  2. 4.597 km SW of San Antonio, Chile16y ago · 9 km S of this epicenter
  3. 4.589 km WNW of Santa Cruz, Chile16y ago · 14 km SE of this epicenter
  4. 3.783 km SW of San Antonio, Chile16y ago · 14 km N of this epicenter
  5. 5.279 km SW of San Antonio, Chile16y ago · 16 km N of this epicenter
  6. 4.267 km SSW of San Antonio, Chile16y ago · 30 km E of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 665 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 · 226 km S of this epicenter
  2. 8.2The 1906 Valparaiso, Chile EarthquakeAugust 17, 1906 · 212 km NE of this epicenter
  3. 8.025 km WSW of Valparaíso, ChileMarch 3, 1985 · 120 km N of this epicenter
  4. 7.826 km WNW of San Carlos, ChileJanuary 25, 1939 · 238 km S of this epicenter
  5. 7.819 km NNE of Hacienda La Calera, ChileJuly 9, 1971 · 201 km NE of this epicenter
  6. 7.730 km NNE of Constitución, ChileDecember 1, 1928 · 104 km S of this epicenter
  7. 7.7103 km NW of Constitución, ChileJanuary 30, 1914 · 114 km SW of this epicenter
  8. 7.47 km SSE of La Ligua, ChileMarch 28, 1965 · 209 km NE of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 38 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 35,597 recorded deaths. The most severe:

  1. 1939M8.3

    Chillan

    25 Jan 1939 · 233 km away · intensity X

    30,000 deaths$920 million damagetsunami

  2. 1906M8.2

    South Central

    17 Aug 1906 · 131 km away · intensity XI

    4,000 deaths$100 million damagetsunami

  3. 2010M8.8

    Maule, Concepcion, Talcahuano

    27 Feb 2010 · 226 km away · intensity IX

    558 deaths$30 billion damagetsunami

  4. 1965M7.3

    Central

    28 Mar 1965 · 220 km away

    400 deaths$125 million damage

  5. 1928M7.6

    Talca, Chillan, Santiago, San Fernando

    1 Dec 1928 · 98 km away · intensity IX

    279 deathsSevere damage ($5–24M)tsunami

  6. 1985M8.0

    Central Coast, San Antonio, Valparaiso

    3 Mar 1985 · 126 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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