Reviewed by USGSIndonesia49y ago
M6.0 earthquake 273 km SW of Waingapu, Indonesia
Saturday, August 20, 1977, 04:20:30 UTC · 11.099°S, 118.240°E
A magnitude 6.0 earthquake struck 273 km SW of Waingapu, Indonesia on Saturday, August 20, 1977, 04:20:30 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M6.1 on August 19, 1977.
- Magnitude
- 6.0
- Strong · ms
- Depth
- 33 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 earthquakeDashed circle: 100 km aftershock search area
In context
How big was it, and why here?
Energy released
15 kilotons of TNT
That is about the energy of the Hiroshima bomb. It released about 32 times the energy of a magnitude 5.0.
Tectonic setting
32 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
33 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 100 km
USGS lists 35 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M6.1 on August 20, 1977. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.6south of Sumbawa, Indonesia49y ago · 59 km SW of this epicenter
- 5.2219 km S of Sumbawa Besar, Indonesia49y ago · 96 km NW of this epicenter
- 5.5south of Sumbawa, Indonesia49y ago · 31 km SW of this epicenter
- 5.2south of Sumbawa, Indonesia49y ago · 50 km SW of this epicenter
- 5.7273 km SW of Waingapu, Indonesia49y ago · 4 km SE of this epicenter
- 6.0195 km SW of Waingapu, Indonesia49y ago · 99 km E of this epicenter
- 5.2217 km SW of Waingapu, Indonesia49y ago · 73 km E of this epicenter
- 5.2229 km SW of Waingapu, Indonesia49y ago · 68 km E of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 73 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.31977 Sumba, Indonesia EarthquakeAugust 19, 1977 · 17 km E of this epicenter
- 7.084 km SSE of Dompu, IndonesiaMay 9, 1922 · 209 km N of this epicenter
- 6.4248 km S of Taliwang, IndonesiaMay 28, 1972 · 141 km W of this epicenter
- 6.377 km WSW of Waingapu, IndonesiaOctober 15, 1923 · 198 km NE of this epicenter
- 6.362 km S of Waingapu, IndonesiaOctober 15, 1923 · 241 km NE of this epicenter
- 6.3139 km SSE of Dompu, IndonesiaDecember 21, 1938 · 160 km N of this epicenter
- 6.3151 km WSW of Waingapu, IndonesiaJanuary 2, 1977 · 132 km NE of this epicenter
- 6.384 km S of Komodo, IndonesiaJanuary 2, 1936 · 242 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 2 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 189 recorded deaths. The most severe:
- 1977M8.3
Sunda Islands
19 Aug 1977 · 17 km away
189 deaths$1 million damagetsunami
- 1837
Sumbawa Island: Bima
28 Nov 1837 · 290 km away · intensity IX
Limited damage (under $1M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.