Reviewed by USGSChile10y ago
M4.9 earthquake 39 km WNW of La Ligua, Chile
Wednesday, September 7, 2016, 22:54:32 UTC · 32.321°S, 71.620°W
A magnitude 4.9 earthquake struck 39 km WNW of La Ligua, Chile on Wednesday, September 7, 2016, 22:54:32 UTC, at a depth of 30.5 km (shallow). USGS received 4 “Did You Feel It?” reports, with a maximum reported intensity of IV (light). It is the strongest earthquake within 300 km since an M5.4 on August 30, 2016.
- Magnitude
- 4.9
- Light · mwr
- Depth
- 30 km
- Shallow
- Felt reports
- 4
- Max intensity IV
- 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
338 tons of TNT
That is about 1/45 of the Hiroshima bomb. A magnitude 5.0 releases about 1 times more energy.
Tectonic setting
107 km
from the nearest mapped plate boundary, between the Nazca and South American plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
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
Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.
| Place | Intensity | Reports | Distance |
|---|---|---|---|
| Llaillay, Valparaíso, Chile | IV · Light | 1 | 91 km |
| Viña del Mar, Valparaíso, Chile | II · Weak | 1 | 82 km |
| Quilpué, Valparaíso, Chile | II · Weak | 1 | 86 km |
| Curicó, Maule, Chile | I · Not felt | 1 | 298 km |
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 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.6 on October 1, 2016. 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 925 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.348 km W of Illapel, ChileSeptember 16, 2015 · 83 km N of this epicenter
- 8.2The 1906 Valparaiso, Chile EarthquakeAugust 17, 1906 · 22 km SE of this epicenter
- 8.145 km NNW of Illapel, ChileApril 6, 1943 · 120 km N of this epicenter
- 8.025 km WSW of Valparaíso, ChileMarch 3, 1985 · 94 km S of this epicenter
- 7.819 km NNE of Hacienda La Calera, ChileJuly 9, 1971 · 54 km SE of this epicenter
- 7.47 km SSE of La Ligua, ChileMarch 28, 1965 · 44 km SE of this epicenter
- 7.419 km S of Valparaíso, ChileMarch 4, 1985 · 99 km S of this epicenter
- 7.237 km S of San Antonio, ChileMarch 18, 1931 · 179 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 55 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 19,080 recorded deaths. The most severe:
- 1861
Mendoza, San Luiz
20 Mar 1861 · 270 km away · intensity IX
14,000 deathsExtreme damage ($25M+)tsunami
- 1906M8.2
South Central
17 Aug 1906 · 84 km away · intensity XI
4,000 deaths$100 million damagetsunami
- 1965M7.3
Central
28 Mar 1965 · 40 km away
400 deaths$125 million damage
- 1928M7.6
Talca, Chillan, Santiago, San Fernando
1 Dec 1928 · 300 km away · intensity IX
279 deathsSevere damage ($5–24M)tsunami
- 1985M8.0
Central Coast, San Antonio, Valparaiso
3 Mar 1985 · 91 km away · intensity VIII
180 deaths$1.5 billion damagetsunami
- 1971M7.8
Central
9 Jul 1971 · 44 km away · intensity IX
83 deaths$236 million damagetsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.