QuakeScout
Magnitude4.2

Reviewed by USGSIndonesia21y ago

M4.2 earthquake 202 km SW of Sibolga, Indonesia

Sunday, October 23, 2005, 18:16:38 UTC · 0.257°N, 97.719°E

A magnitude 4.2 earthquake struck 202 km SW of Sibolga, Indonesia on Sunday, October 23, 2005, 18:16:38 UTC, at a depth of 30.0 km (shallow).

Magnitude
4.2
Light · mb
Depth
30 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

30 tons of TNT

That is about 1/500 of the Hiroshima bomb. A magnitude 5.0 releases about 16 times more energy.

Tectonic setting

77 km

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

Depth: shallow

30 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 345 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 8.678 km WSW of Singkil, IndonesiaMarch 28, 2005 · 214 km N of this epicenter
  2. 7.6212 km W of Pariaman, IndonesiaDecember 28, 1935 · 83 km SE of this epicenter
  3. 7.1190 km SSW of Sibolga, IndonesiaNovember 17, 1984 · 35 km E of this epicenter
  4. 7.095 km W of Pariaman, IndonesiaApril 1, 1998 · 193 km SE of this epicenter
  5. 7.0122 km W of Pariaman, IndonesiaMay 8, 1946 · 182 km SE of this epicenter
  6. 7.0102 km SW of Padangsidempuan, IndonesiaFebruary 4, 1971 · 120 km E of this epicenter
  7. 6.9181 km SW of Sibolga, IndonesiaDecember 4, 1974 · 20 km NE of this epicenter
  8. 6.989 km WSW of Singkil, IndonesiaMay 19, 2005 · 207 km N of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 16 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 3,676 recorded deaths. The most severe:

  1. 2005M8.6

    Sumatera: Sw

    28 Mar 2005 · 214 km away

    1,319 deaths$37 million damagetsunami

  2. 1861M8.5

    Lagundi, Simuk, Tello I

    16 Feb 1861 · 142 km away · intensity IX

    1,105 deathsModerate damage ($1–5M)tsunami

  3. 1861M7.0

    Sw. Sumatra

    9 Mar 1861 · 42 km away

    950 deathsSevere damage ($5–24M)tsunami

  4. 1797M8.0

    Sw. Sumatra

    10 Feb 1797 · 145 km away · intensity IX

    300 deathsModerate damage ($1–5M)tsunami

  5. 1987M6.6

    Sumatera: N, Tarutung-Lake Toba,

    25 Apr 1987 · 255 km away

    2 deaths$1 million damage

  6. 1843M7.3

    Sw. Sumatra

    5 Jan 1843 · 142 km away · intensity XI

    Severe damage ($5–24M)tsunami

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

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