M5.5 earthquake 81 km WSW of San Antonio, Chile
A magnitude 5.5 earthquake struck 81 km WSW of San Antonio, Chile on Sat, Dec 1, 2018, 8:55 PM GMT-3 (23:55 UTC), 10 km (6 mi) below the surface.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 5.5 (Mww, W-phase moment), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 2018-12-01 23:55:24 UTC
- Depth
- 10.0 km (6.2 mi), shallow
- Epicenter
- 33.922° S, 72.401° W
- Region
- Chile
- Felt reports
- 17
- Strongest shaking
- IV, light shaking
- PAGER alert
- Green
- Tsunami flag
- No
- Status
- Reviewed by a seismologist
Magnitude estimates
Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.
| Mag. | Scale | Computed by | Notes |
|---|---|---|---|
| 5.5 | Mww, W-phase moment | USGS National Earthquake Information Center | Preferred · Reviewed · ±0.052 · 35 stations |
| 5.56 | Mw, moment | ISC-GEM global catalog | Final · ±0.1 |
| 5.5 | Mwb, body-wave moment | USGS National Earthquake Information Center | Moment tensor · Reviewed |
| 5.4 | Mwr, regional moment | USGS National Earthquake Information Center | Moment tensor · Reviewed |
Shaking
The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.
- Strongest estimated
- IV, light shaking
- Peak ground acceleration
- 264.0% of gravity
- Peak ground velocity
- 1.7 cm/s
- Map
- Automatic
Did you feel it?
17 people reported to the USGS what they felt; the strongest reported shaking was VII, very strong shaking.
Estimated impact
The USGS PAGER system estimates deaths and economic losses from the shaking and the population and buildings exposed to it.
- Alert level
- Green: little or no damage or loss of life expected
| Range | Chance |
|---|---|
| Under 1 | 65% |
| 1 to 10 | 30% |
| 10 to 100 | 4% |
| 100 to 1,000 | Under 1% |
| 1,000 to 10,000 | Under 1% |
| 10,000 to 100,000 | Under 1% |
| 100,000 to 10,000,000 | Under 1% |
| Range, million USD | Chance |
|---|---|
| Under 1 | 65% |
| 1 to 10 | 30% |
| 10 to 100 | 4% |
| 100 to 1,000 | Under 1% |
| 1,000 to 10,000 | Under 1% |
| 10,000 to 100,000 | Under 1% |
| 100,000 to 10,000,000 | Under 1% |
Fault motion and ground failure
How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.
- Faulting
- Reverse (thrust)
- Moment magnitude
- 5.5 Mww
- Nodal plane 1
- Strike 18°, dip 19°, rake 101°
- Nodal plane 2
- Strike 187°, dip 71°, rake 86°
How well it is located
Reviewed by a seismologist.
- Location uncertainty
- About 3.2 km horizontally, 1.5 km in depth
- Magnitude uncertainty
- ±0.05
- Depth from
- Operator assigned
- Station coverage gap
- 47°
- Stations used
- 277
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 2.5 and up: 4 in the 60 days after this one and 1 in the 30 days before it.
After
- 4.781 km WSW of San Antonio, Chile · 2862 days ago · 19 km deep · 3 km away · felt by 1
- 4.488 km WSW of San Antonio, Chile · 2861 days ago · 14 km deep · 12 km away
- 4.185 km WSW of San Antonio, Chile · 2861 days ago · 10 km deep · 5 km away
- 5.07 km SSW of San Antonio, Chile · 2858 days ago · 35 km deep · 77 km away · felt by 139
Before
Earthquakes todayChile earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event us1000i02j (also filed as iscgem616643659). Read Fri, Oct 2, 2026, 9:27 PM UTC.