QuakeScout
Magnitude4.9

Reviewed by USGSChile40y ago

M4.9 earthquake 33 km S of Antofagasta, Chile

Saturday, April 4, 1987, 19:46:24 UTC · 23.955°S, 70.372°W

A magnitude 4.9 earthquake struck 33 km S of Antofagasta, Chile on Saturday, April 4, 1987, 19:46:24 UTC, at a depth of 41.3 km (shallow). It is the strongest earthquake within 300 km since an M6.1 on March 22, 1987.

Magnitude
4.9
Light · mb
Depth
41 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 earthquake

In context

How big was it, and why here?

Energy released

338 tons of TNT

That is about 1/45 of the Hiroshima bomb. A magnitude 5.0 releases about 1 times more energy.

Tectonic setting

108 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

41 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 has not published any M2.5+ earthquake within 50 km in the 30 days after this event.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 243 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 8.2121 km SSE of San Pedro de Atacama, ChileDecember 9, 1950 · 250 km E of this epicenter
  2. 8.060 km W of Diego de Almagro, ChileDecember 4, 1918 · 280 km S of this epicenter
  3. 7.79 km SSW of Taltal, ChileDecember 28, 1966 · 171 km S of this epicenter
  4. 7.684 km SSE of Antofagasta, ChileMarch 5, 1987 · 53 km SE of this epicenter
  5. 7.583 km NNE of Taltal, ChileJuly 13, 1936 · 88 km S of this epicenter
  6. 7.550 km WNW of Diego de Almagro, ChileJune 8, 1909 · 245 km S of this epicenter
  7. 7.454 km WSW of Diego de Almagro, ChileOctober 4, 1983 · 288 km S of this epicenter
  8. 7.334 km NE of Tocopilla, ChileDecember 21, 1967 · 235 km N of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 28 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2,403 recorded deaths. The most severe:

  1. 1877M8.3

    Off North Coast

    10 May 1877 · 273 km away · intensity XI

    2,385 deaths$2 million damagetsunami

  2. 1983M7.3

    Northern: Copoapo-Chanaral

    4 Oct 1983 · 288 km away · intensity VII

    5 deaths$1 million damagetsunami

  3. 1953M7.4

    Northern

    7 Dec 1953 · 268 km away

    3 deaths$7 million damage

  4. 1966M7.8

    Taltal, Catalina

    28 Dec 1966 · 175 km away · intensity VIII

    3 deathsUnder $1 million damagetsunami

  5. 1946M7.9

    Northern

    2 Aug 1946 · 283 km away

    2 deathsSevere damage ($5–24M)tsunami

  6. 1967M7.5

    Northern

    21 Dec 1967 · 266 km away

    1 deathModerate damage ($1–5M)tsunami

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

Nearby trackers

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