Earthquakes on December 20, 2021
403
EARTHQUAKES on December 20, 2021
24-hour UTC period · USGS data
LARGEST: M6.2 — 7km N of Petrolia, CA
27 km deep · 4,378 people felt it
Elevated activitycompared to daily average (~250/day)
Magnitude Breakdown
M5.0+
5
M4.0–4.9
31
M3.0–3.9
23
M2.0–2.9
126
M1.0–1.9
218
Activity Summary
403
Total earthquakes
~250
Daily average
Elevated
Activity level
5
M5.0+ events
Geographic Breakdown
Top Countries (International)
South Sandwich Islands
2
Northern Mariana Islands
1
Significant Earthquakes (M4.5+)
6.2
7km N of Petrolia, CA
20:10 UTC · 27.0 km deep
Felt by 4,378
5.9
South Sandwich Islands region
03:39 UTC · 10.0 km deep
5.7
29km W of Petrolia, CA
20:10 UTC · 16.5 km deep
05.1
25 km ENE of Shizunai-furukawach?, Japan
16:05 UTC · 40.8 km deep
Felt by 4
5.0
40 km N of Burruyacú, Argentina
16:34 UTC · 10.0 km deep
Felt by 3
4.9
287 km WNW of Longyearbyen, Svalbard and Jan Mayen
17:22 UTC · 10.0 km deep
4.9
114 km E of Madang, Papua New Guinea
01:36 UTC · 238.9 km deep
Felt by 3
4.8
52km W of Petrolia, CA
20:13 UTC · 19.9 km deep
Felt by 8
Earthquake Map — December 20, 2021
All Earthquakes — December 20, 2021
Showing 30 of 185 (filtered from 403)
(Filtered to M2.0+. Change the magnitude filter to see smaller events.)
| Time ↓ | Mag ↕ | Location ↕ | Depth ↕ | Felt ↕ | MMI | Alert | Status | Details |
|---|---|---|---|---|---|---|---|---|
2021-12-20 2021-12-20 23:57:22 UTC | 2.7ml | 75 km WSW of Cantwell, Alaska 63.206°, -150.395° | 115.0 km | - | - | - | ✓ Reviewed | USGS → |
Seismographs logged a magnitude 2.7 earthquake 75 km WSW of Cantwell, Alaska with origin time 23:57 UTC on December 20, 2021. See the M2.7 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 23:49:19 UTC | 2.1md | 0 km NNE of P?hala, Hawaii 19.208°, -155.477° | 35.8 km | - | - | - | Auto | USGS → |
At 23:49 UTC on December 20, 2021, a magnitude 2.1 tremor occurred 0 km NNE of P?hala, Hawaii. It arrived roughly 17 hours after a larger magnitude 2.9 mainshock in the same 20 km area, placing it within the typical aftershock window. See the M2.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 23:40:29 UTC | 3.0ml | 8km SSW of Ferndale, CA 40.505°, -124.296° | 18.4 km | 1 | - | - | ✓ Reviewed | USGS → |
December 20, 2021 brought a magnitude 3.0 earthquake 8km SSW of Ferndale, CA, logged at 23:40 UTC. Coming 3 hours after a magnitude 6.2 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. See the M3.0 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 23:25:14 UTC | 2.8md | 14km N of Petrolia, CA 40.449°, -124.305° | 23.3 km | - | - | - | ✓ Reviewed | USGS → |
Reports of a magnitude 2.8 earthquake 14km N of Petrolia, CA came in on December 20, 2021 at 23:25 UTC. Coming 3 hours after a magnitude 6.2 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. The event was offshore. See the M2.8 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 23:21:36 UTC | 2.3md | 11km SSW of Ferndale, CA 40.481°, -124.310° | 18.8 km | - | - | - | ✓ Reviewed | USGS → |
Seismographs logged a magnitude 2.3 earthquake 11km SSW of Ferndale, CA with origin time 23:21 UTC on December 20, 2021. It arrived roughly 3 hours after a larger magnitude 6.2 mainshock in the same 20 km area, placing it within the typical aftershock window. See the M2.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 23:18:41 UTC | 2.2md | 8km N of Petrolia, CA 40.394°, -124.277° | 26.3 km | - | - | - | ✓ Reviewed | USGS → |
This magnitude 2.2 event was detected 8km N of Petrolia, CA on December 20, 2021, with origin time 23:18 UTC. It arrived roughly 3 hours after a larger magnitude 6.2 mainshock in the same 20 km area, placing it within the typical aftershock window. The event was offshore. See the M2.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 23:18:17 UTC | 2.7md | 29km W of Petrolia, CA 40.324°, -124.624° | 20.6 km | 1 | - | - | ✓ Reviewed | USGS → |
This magnitude 2.7 event was detected 29km W of Petrolia, CA on December 20, 2021, with origin time 23:18 UTC. Coming 3 hours after a magnitude 5.7 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. The event was offshore. See the M2.7 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 23:12:43 UTC | 2.6md | 21km W of Petrolia, CA 40.292°, -124.530° | 20.5 km | - | - | - | ✓ Reviewed | USGS → |
On December 20, 2021 at 23:12 UTC, a magnitude 2.6 earthquake struck 21km W of Petrolia, CA. It arrived roughly 3 hours after a larger magnitude 5.7 mainshock in the same 20 km area, placing it within the typical aftershock window. The event was offshore. See the M2.6 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 23:11:41 UTC | 2.4md | 7km NNW of Petrolia, CA 40.383°, -124.301° | 26.3 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 2.4 earthquake 7km NNW of Petrolia, CA at 23:11 UTC on December 20, 2021. Coming 3 hours after a magnitude 6.2 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. See the M2.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 23:06:20 UTC | 3.0md | 6 km SE of Maria Antonia, Puerto Rico 17.945°, -66.844° | 13.0 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 3.0 earthquake 6 km SE of Maria Antonia, Puerto Rico at 23:06 UTC on December 20, 2021. The event was offshore. See the M3.0 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 23:02:26 UTC | 2.5md | 12km SW of Rio Dell, CA 40.431°, -124.218° | 27.7 km | - | - | - | ✓ Reviewed | USGS → |
At 23:02 UTC on December 20, 2021, a magnitude 2.5 tremor occurred 12km SW of Rio Dell, CA. Coming 3 hours after a magnitude 6.2 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. The event was offshore. See the M2.5 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:59:55 UTC | 2.0md | 11km NNE of Petrolia, CA 40.416°, -124.237° | 27.5 km | - | - | - | ✓ Reviewed | USGS → |
Reports of a magnitude 2.0 earthquake 11km NNE of Petrolia, CA came in on December 20, 2021 at 22:59 UTC. It arrived roughly 3 hours after a larger magnitude 6.2 mainshock in the same 20 km area, placing it within the typical aftershock window. See the M2.0 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:57:54 UTC | 2.6md | 22km SW of Ferndale, CA 40.466°, -124.479° | 27.0 km | - | - | - | ✓ Reviewed | USGS → |
Seismographs logged a magnitude 2.6 earthquake 22km SW of Ferndale, CA with origin time 22:57 UTC on December 20, 2021. Coming 3 hours after a magnitude 6.2 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. The event was offshore. See the M2.6 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:56:32 UTC | 4.3mb | 283 km WNW of Attu Station, Alaska 54.048°, 169.424° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 4.3 earthquake 283 km WNW of Attu Station, Alaska at 22:56 UTC on December 20, 2021. See the M4.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:51:08 UTC | 2.8md | 29km W of Petrolia, CA 40.326°, -124.630° | 19.0 km | 3 | - | - | ✓ Reviewed | USGS → |
Reports of a magnitude 2.8 earthquake 29km W of Petrolia, CA came in on December 20, 2021 at 22:51 UTC. This event falls inside the aftershock decay of a nearby magnitude 5.7 earthquake that occurred about 3 hours earlier. The event was offshore. See the M2.8 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:45:27 UTC | 2.8md | 33km W of Petrolia, CA 40.319°, -124.674° | 19.0 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 2.8 seismic event took place 33km W of Petrolia, CA on December 20, 2021 at 22:45 UTC. Coming 3 hours after a magnitude 5.7 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. The event was offshore. See the M2.8 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:43:43 UTC | 4.5mb | Volcano Islands, Japan region 22.359°, 143.767° | 114.1 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 4.5 earthquake was recorded in the Volcano Islands, Japan region on December 20, 2021 at 22:43 UTC. See the M4.5 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:43:14 UTC | 2.3md | 3 km SE of P?hala, Hawaii 19.179°, -155.455° | 37.2 km | - | - | - | Auto | USGS → |
A magnitude 2.3 earthquake was recorded 3 km SE of P?hala, Hawaii on December 20, 2021 at 22:43 UTC. Coming 16 hours after a magnitude 2.9 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. The event was offshore. See the M2.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:40:00 UTC | 2.6md | 10km NNW of Petrolia, CA 40.411°, -124.309° | 25.9 km | - | - | - | ✓ Reviewed | USGS → |
December 20, 2021 brought a magnitude 2.6 earthquake 10km NNW of Petrolia, CA, logged at 22:40 UTC. It arrived roughly 2 hours after a larger magnitude 6.2 mainshock in the same 20 km area, placing it within the typical aftershock window. See the M2.6 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:33:31 UTC | 2.3md | 20km NNE of Redway, CA 40.294°, -123.767° | 25.9 km | 3 | - | - | ✓ Reviewed | USGS → |
On December 20, 2021 at 22:33 UTC, a magnitude 2.3 earthquake struck 20km NNE of Redway, CA. See the M2.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:25:08 UTC | 2.8ml | 196 km W of Adak, Alaska 51.873°, -179.489° | 121.2 km | - | - | - | ✓ Reviewed | USGS → |
December 20, 2021 brought a magnitude 2.8 earthquake 196 km W of Adak, Alaska, logged at 22:25 UTC. The event was offshore. See the M2.8 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:19:15 UTC | 2.3md | 7km NNE of Petrolia, CA 40.389°, -124.263° | 23.0 km | 4 | - | - | ✓ Reviewed | USGS → |
On December 20, 2021, worldwide seismic activity registered a magnitude 2.3 earthquake 7km NNE of Petrolia, CA at 22:19 UTC. This event falls inside the aftershock decay of a nearby magnitude 6.2 earthquake that occurred about 2 hours earlier. See the M2.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:17:55 UTC | 2.4md | 4 km S of Guánica, Puerto Rico 17.933°, -66.910° | 11.0 km | - | - | - | ✓ Reviewed | USGS → |
Reports of a magnitude 2.4 earthquake 4 km S of Guánica, Puerto Rico came in on December 20, 2021 at 22:17 UTC. It arrived roughly 15 hours after a larger magnitude 2.6 mainshock in the same 20 km area, placing it within the typical aftershock window. The event was offshore. See the M2.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:10:14 UTC | 2.4md | 10km NNE of Petrolia, CA 40.409°, -124.247° | 24.0 km | - | - | - | ✓ Reviewed | USGS → |
This magnitude 2.4 event was detected 10km NNE of Petrolia, CA on December 20, 2021, with origin time 22:10 UTC. It arrived roughly 2 hours after a larger magnitude 6.2 mainshock in the same 20 km area, placing it within the typical aftershock window. See the M2.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:09:15 UTC | 2.6md | 8km W of Petrolia, CA 40.333°, -124.372° | 31.4 km | 2 | - | - | ✓ Reviewed | USGS → |
This magnitude 2.6 event was detected 8km W of Petrolia, CA on December 20, 2021, with origin time 22:09 UTC. It arrived roughly 2 hours after a larger magnitude 6.2 mainshock in the same 20 km area, placing it within the typical aftershock window. The event was offshore. See the M2.6 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 22:08:18 UTC | 2.2ml | 52 km NE of Kobuk, Alaska 67.295°, -156.201° | 20.9 km | - | - | - | ✓ Reviewed | USGS → |
At 22:08 UTC on December 20, 2021, a magnitude 2.2 tremor occurred 52 km NE of Kobuk, Alaska. It arrived roughly 12 hours after a larger magnitude 2.7 mainshock in the same 20 km area, placing it within the typical aftershock window. The event was offshore. See the M2.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 21:53:46 UTC | 3.9mw | 6km NE of Petrolia, CA 40.358°, -124.226° | 26.9 km | 1 | III | - | ✓ Reviewed | USGS → |
Reports of a magnitude 3.9 earthquake 6km NE of Petrolia, CA came in on December 20, 2021 at 21:53 UTC. This event falls inside the aftershock decay of a nearby magnitude 6.2 earthquake that occurred about 2 hours earlier. The event was offshore. See the M3.9 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 21:52:53 UTC | 3.3ml | 18km SW of Ferndale, CA 40.475°, -124.425° | 25.1 km | 2 | II | - | ✓ Reviewed | USGS → |
This magnitude 3.3 event was detected 18km SW of Ferndale, CA on December 20, 2021, with origin time 21:52 UTC. This event falls inside the aftershock decay of a nearby magnitude 6.2 earthquake that occurred about 2 hours earlier. The event was offshore. See the M3.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 21:52:03 UTC | 2.2md | 12km SSW of Ferndale, CA 40.481°, -124.320° | 21.1 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 2.2 earthquake 12km SSW of Ferndale, CA at 21:52 UTC on December 20, 2021. This event falls inside the aftershock decay of a nearby magnitude 6.2 earthquake that occurred about 2 hours earlier. See the M2.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-12-20 2021-12-20 21:51:53 UTC | 2.3md | 12km SW of Rio Dell, CA 40.435°, -124.221° | 29.4 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 2.3 earthquake 12km SW of Rio Dell, CA at 21:51 UTC on December 20, 2021. It arrived roughly 2 hours after a larger magnitude 6.2 mainshock in the same 20 km area, placing it within the typical aftershock window. The event was offshore. See the M2.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
Legend:
Mag: Magnitude (magType = ml, mb, mw, etc.)
Felt: Number of DYFI felt reports
MMI: Modified Mercalli Intensity (I-X+)
Alert: PAGER alert level
Depth: Shallow (<70km), Intermediate, Deep (>300km)
Status: Auto = preliminary, Reviewed = verified by seismologist
Click any row to see additional technical details.
About This Page
This page shows all earthquakes recorded by the USGS Earthquake Hazards Program during the 24-hour UTC period on December 20, 2021. Data includes all events of magnitude 1.0 or greater. Past earthquake data is considered final after review by USGS seismologists.