Reviewed by USGSIndonesia52y ago
M4.7 earthquake 254 km SSW of Kroya, Indonesia
Thursday, September 12, 1974, 04:42:11 UTC · 9.820°S, 108.540°E
A magnitude 4.7 earthquake struck 254 km SSW of Kroya, Indonesia on Thursday, September 12, 1974, 04:42:11 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M6.5 on September 7, 1974.
- Magnitude
- 4.7
- Light · mb
- 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: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
169 tons of TNT
That is about 1/89 of the Hiroshima bomb. A magnitude 5.0 releases about 3 times more energy.
Tectonic setting
43 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 50 km
USGS lists 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M4.5 on September 21, 1974. 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 34 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.6233 km S of Pundong, IndonesiaSeptember 11, 1921 · 233 km E of this epicenter
- 7.487 km SSW of Srandakan, IndonesiaJuly 23, 1943 · 195 km NE of this epicenter
- 7.1138 km SSE of Pundong, IndonesiaSeptember 10, 1926 · 240 km E of this epicenter
- 6.992 km S of Pundong, IndonesiaSeptember 27, 1937 · 237 km NE of this epicenter
- 6.5260 km SSW of Kroya, IndonesiaSeptember 7, 1974 · 20 km W of this epicenter
- 6.5south of Java, IndonesiaDecember 12, 1924 · 291 km SE of this epicenter
- 6.4244 km SSW of Trenggalek, IndonesiaMay 29, 1955 · 267 km E of this epicenter
- 6.3136 km S of Kawalu, IndonesiaSeptember 14, 1944 · 145 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 10 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 217 recorded deaths. The most severe:
- 1943M8.1
Java: Jogyakarta
23 Jul 1943 · 164 km away · intensity VIII
213 deathsSevere damage ($5–24M)
- 1859
S. Java Sea
20 Oct 1859 · 285 km away
2 deathsLimited damage (under $1M)tsunami
- 1937M7.2
Java: Jogyakarta: Klumpit,Prambanan
27 Sep 1937 · 188 km away · intensity IX
1 deathSevere damage ($5–24M)
- 1971M5.2
Java: Buaran,Bantar Kawsun,Jipang
16 Jun 1971 · 298 km away
1 deathSevere damage ($5–24M)
- 1840M7.0
Java: Purworejo
4 Jan 1840 · 295 km away · intensity IX
Severe damage ($5–24M)tsunami
- 1863
Java: Banyumas
31 Jul 1863 · 271 km away
Moderate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.