Reviewed by USGSIndonesia50y ago
M5.0 earthquake 83 km N of Sinabang, Indonesia
Sunday, August 1, 1976, 02:02:50 UTC · 3.226°N, 96.493°E
A magnitude 5.0 earthquake struck 83 km N of Sinabang, Indonesia on Sunday, August 1, 1976, 02:02:50 UTC, at a depth of 81.0 km (intermediate). It is the strongest earthquake within 300 km since an M5.2 on July 23, 1976.
- Magnitude
- 5.0
- Moderate · mb
- Depth
- 81 km
- Intermediate
- Felt reports
- 0
- Did You Feel It?
- 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
477 tons of TNT
That is about 1/32 of the Hiroshima bomb. Each whole step in magnitude is about 32 times more energy.
Tectonic setting
8 km
from the nearest mapped plate boundary, between the Cocos and Nazca plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: intermediate
81 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 75 km
USGS lists 2 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.1 on August 29, 1976. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 101 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.2The 1907 Sumatra Earthquake and TsunamiJanuary 4, 1907 · 123 km SW of this epicenter
- 7.5209 km WSW of Sinabang, IndonesiaNovember 21, 1969 · 253 km SW of this epicenter
- 7.186 km WSW of Pangkalan Brandan, IndonesiaSeptember 19, 1936 · 131 km NE of this epicenter
- 7.040 km NE of Meulaboh, IndonesiaAugust 3, 1935 · 129 km N of this epicenter
- 7.085 km SSE of Meulaboh, IndonesiaJune 20, 1976 · 27 km NW of this epicenter
- 6.928 km NNE of Sinabang, IndonesiaNovember 4, 1917 · 58 km S of this epicenter
- 6.975 km WSW of Banda Aceh, IndonesiaAugust 23, 1936 · 300 km NW of this epicenter
- 6.95 km W of Banda Aceh, IndonesiaApril 2, 1964 · 291 km NW 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 2,219 recorded deaths. The most severe:
- 1907M8.2
Nw Sumatra: Gunungsitoli, Barus
4 Jan 1907 · 123 km away
2,188 deathsSevere damage ($5–24M)tsunami
- 1936
N Sumatera: Tapanuli, Karo
9 Sep 1936 · 116 km away · intensity VIII
17 deathsModerate damage ($1–5M)
- 1967M6.1
N Sumatera,Malay Peninsula
12 Apr 1967 · 268 km away
14 deathsSevere damage ($5–24M)tsunami
- 1843M7.3
Sw. Sumatra
5 Jan 1843 · 255 km away · intensity XI
Severe damage ($5–24M)tsunami
- 1837M7.3
Banda Atjeh
29 Sep 1837 · 259 km away
Moderate damage ($1–5M)tsunami
- 1969M7.7
Off Nw Coast Sumatera
21 Nov 1969 · 245 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.