Reviewed by USGSIndonesia27y ago
M5.6 earthquake 96 km SSW of Luwuk, Indonesia
Friday, August 13, 1999, 10:12:20 UTC · 1.776°S, 122.492°E
A magnitude 5.6 earthquake struck 96 km SSW of Luwuk, Indonesia on Friday, August 13, 1999, 10:12:20 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M6.2 on August 12, 1999.
- Magnitude
- 5.6
- Moderate · mwc
- Depth
- 33 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- V
- Moderate (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 75 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
4 kilotons of TNT
That is about 1/4 of the Hiroshima bomb. It released about 8 times the energy of a magnitude 5.0.
Tectonic setting
70 km
from the nearest mapped plate boundary, between the Molucca Sea and Banda Sea 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 75 km
USGS lists 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M4.5 on August 17, 1999. 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 435 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.11939 Sulawesi EarthquakeDecember 21, 1939 · 198 km N of this epicenter
- 7.8160 km W of Gorontalo, IndonesiaJanuary 22, 1905 · 282 km N of this epicenter
- 7.7120 km NE of Palu, IndonesiaMay 19, 1938 · 290 km NW of this epicenter
- 7.7264 km ESE of Luwuk, IndonesiaNovember 29, 1998 · 269 km E of this epicenter
- 7.433 km NW of Gorontalo, IndonesiaNovember 8, 1941 · 281 km N of this epicenter
- 7.491 km SW of Gorontalo, IndonesiaAugust 6, 1984 · 188 km N of this epicenter
- 6.977 km NNW of Masamba, IndonesiaJune 7, 1968 · 269 km W of this epicenter
- 6.8161 km S of Luwuk, IndonesiaNovember 19, 1913 · 68 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 108 recorded deaths. The most severe:
- 1927M6.2
Sulawesi: Donggala
1 Dec 1927 · 218 km away · intensity VII
50 deathsSevere damage ($5–24M)tsunami
- 1998M7.7
Mangole, Manado, Taliabu
29 Nov 1998 · 269 km away · intensity VII
41 deaths$200 million damagetsunami
- 1938M7.7
Sulawesi Island
19 May 1938 · 290 km away · intensity IX
17 deathsSevere damage ($5–24M)tsunami
- 1939M8.0
Centrtal Sulawesi: Kalo,Luwuk,Sula I
21 Dec 1939 · 205 km away
Moderate damage ($1–5M)tsunami
- 1907
Sulawesi: Lemo, Colo, Anja, Olu Congko
30 Jul 1907 · 168 km away · intensity VIII
Moderate damage ($1–5M)
- 1960
Central Sulawesi: Una-Una Island
29 Apr 1960 · 180 km away · intensity VIII
Moderate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.