Earthquakes on August 16, 2021
356
EARTHQUAKES on August 16, 2021
24-hour UTC period · USGS data
LARGEST: M6.9 — South Sandwich Islands region
17 km deep · 3 people felt it
Elevated activitycompared to daily average (~250/day)
Magnitude Breakdown
M5.0+
12
M4.0–4.9
85
M3.0–3.9
9
M2.0–2.9
66
M1.0–1.9
184
Activity Summary
356
Total earthquakes
~250
Daily average
Elevated
Activity level
12
M5.0+ events
Geographic Breakdown
By US State
Significant Earthquakes (M4.5+)
6.9
South Sandwich Islands region
11:10 UTC · 16.7 km deep
Felt by 3
5.7
South Sandwich Islands region
05:46 UTC · 16.4 km deep
5.5
South Sandwich Islands region
23:37 UTC · 41.5 km deep
5.5
South Sandwich Islands region
20:50 UTC · 10.0 km deep
5.3
South Sandwich Islands region
08:46 UTC · 35.0 km deep
5.2
South Sandwich Islands region
10:23 UTC · 35.0 km deep
5.1
South Sandwich Islands region
19:17 UTC · 10.0 km deep
5.1
South Sandwich Islands region
14:36 UTC · 50.2 km deep
Earthquake Map — August 16, 2021
All Earthquakes — August 16, 2021
Showing 30 of 172 (filtered from 356)
(Filtered to M2.0+. Change the magnitude filter to see smaller events.)
| Time ↓ | Mag ↕ | Location ↕ | Depth ↕ | Felt ↕ | MMI | Alert | Status | Details |
|---|---|---|---|---|---|---|---|---|
2021-08-16 2021-08-16 23:58:56 UTC | 4.6mb | 6 km NW of Petrinja, Croatia 45.475°, 16.234° | 10.0 km | 44 | - | - | ✓ Reviewed | USGS → |
On August 16, 2021 at 23:58 UTC, a magnitude 4.6 earthquake struck 6 km NW of Petrinja, Croatia. The event was offshore. See the M4.6 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 23:37:24 UTC | 5.5mww | South Sandwich Islands region -59.540°, -26.302° | 41.5 km | - | III | green | ✓ Reviewed | USGS → |
Seismographs logged a magnitude 5.5 earthquake in the South Sandwich Islands region with origin time 23:37 UTC on August 16, 2021. The USGS PAGER system assigned a green alert level for this event, signalling no significant casualties or damage expected. See the M5.5 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 23:34:12 UTC | 2.2md | 40km NNE of Toms Place, CA 37.906°, -118.557° | 0.9 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 2.2 earthquake 40km NNE of Toms Place, CA at 23:34 UTC on August 16, 2021. This very shallow event was close enough to the surface that even modest magnitudes can produce significant local shaking. See the M2.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 23:24:51 UTC | 4.6mb | South Sandwich Islands region -58.661°, -24.932° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 4.6 earthquake was recorded in the South Sandwich Islands region on August 16, 2021 at 23:24 UTC. It arrived roughly 2 hours after a larger magnitude 4.7 mainshock in the same 20 km area, placing it within the typical aftershock window. See the M4.6 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 23:12:52 UTC | 2.2ml | 95 km E of Yakutat, Alaska 59.672°, -138.055° | 6.0 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 2.2 seismic event took place 95 km E of Yakutat, Alaska on August 16, 2021 at 23:12 UTC. The event was offshore. See the M2.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 23:04:53 UTC | 4.7mb | South Sandwich Islands region -59.801°, -26.216° | 35.0 km | - | - | - | ✓ Reviewed | USGS → |
This magnitude 4.7 event was detected in the South Sandwich Islands region on August 16, 2021, with origin time 23:04 UTC. This event falls inside the aftershock decay of a nearby magnitude 5.3 earthquake that occurred about 14 hours earlier. See the M4.7 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 22:59:37 UTC | 4.2mb | South Sandwich Islands region -57.638°, -24.934° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 4.2 earthquake in the South Sandwich Islands region at 22:59 UTC on August 16, 2021. See the M4.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 22:55:47 UTC | 2.6ml | 158 km SE of Perryville, Alaska 55.028°, -157.184° | 42.5 km | - | - | - | ✓ Reviewed | USGS → |
Seismographs logged a magnitude 2.6 earthquake 158 km SE of Perryville, Alaska with origin time 22:55 UTC on August 16, 2021. The event was offshore. See the M2.6 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 22:55:09 UTC | 2.0ml | 94 km SSE of Sand Point, Alaska 54.566°, -159.868° | 14.4 km | - | - | - | ✓ Reviewed | USGS → |
On August 16, 2021, worldwide seismic activity registered a magnitude 2.0 earthquake 94 km SSE of Sand Point, Alaska at 22:55 UTC. See the M2.0 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 22:54:44 UTC | 4.6mb | South Sandwich Islands region -59.983°, -26.104° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
Seismographs logged a magnitude 4.6 earthquake in the South Sandwich Islands region with origin time 22:54 UTC on August 16, 2021. See the M4.6 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 22:34:44 UTC | 4.6mb | South Sandwich Islands region -58.420°, -25.032° | 21.7 km | - | - | - | ✓ Reviewed | USGS → |
On August 16, 2021, worldwide seismic activity registered a magnitude 4.6 earthquake in the South Sandwich Islands region at 22:34 UTC. See the M4.6 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 22:30:18 UTC | 2.0md | 9 km NNW of Volcano, Hawaii 19.521°, -155.273° | 1.3 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 2.0 earthquake was recorded 9 km NNW of Volcano, Hawaii on August 16, 2021 at 22:30 UTC. This very shallow event was close enough to the surface that even modest magnitudes can produce significant local shaking. See the M2.0 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 22:22:58 UTC | 2.2ml | 91 km SSE of Perryville, Alaska 55.107°, -158.842° | 19.5 km | - | - | - | ✓ Reviewed | USGS → |
August 16, 2021 brought a magnitude 2.2 earthquake 91 km SSE of Perryville, Alaska, logged at 22:22 UTC. See the M2.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 22:22:50 UTC | 4.6mb | South Sandwich Islands region -60.444°, -25.970° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
At 22:22 UTC on August 16, 2021, a magnitude 4.6 tremor occurred in the South Sandwich Islands region. See the M4.6 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 21:53:25 UTC | 4.7mb | South Sandwich Islands region -58.363°, -23.662° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
Reports of a magnitude 4.7 earthquake in the South Sandwich Islands region came in on August 16, 2021 at 21:53 UTC. Coming 11 hours after a magnitude 6.9 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. See the M4.7 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 21:40:23 UTC | 2.1ml | 6 km E of P?hala, Hawaii 19.211°, -155.414° | 29.4 km | - | - | - | Auto | USGS → |
This magnitude 2.1 event was detected 6 km E of P?hala, Hawaii on August 16, 2021, with origin time 21:40 UTC. It arrived roughly 1 hours after a larger magnitude 3.1 mainshock in the same 20 km area, placing it within the typical aftershock window. The event was offshore. See the M2.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 21:31:50 UTC | 2.7ml | 135 km ESE of Chignik, Alaska 55.785°, -156.430° | 49.4 km | - | - | - | ✓ Reviewed | USGS → |
On August 16, 2021 at 21:31 UTC, a magnitude 2.7 earthquake struck 135 km ESE of Chignik, Alaska. See the M2.7 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 21:27:33 UTC | 2.4ml | 22 km W of Nikiski, Alaska 60.692°, -151.698° | 73.4 km | - | - | - | ✓ Reviewed | USGS → |
At 21:27 UTC on August 16, 2021, a magnitude 2.4 tremor occurred 22 km W of Nikiski, Alaska. The event was offshore. See the M2.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 21:19:17 UTC | 3.1ml | 6 km ENE of P?hala, Hawaii 19.226°, -155.421° | 33.4 km | 2 | - | - | ✓ Reviewed | USGS → |
On August 16, 2021, worldwide seismic activity registered a magnitude 3.1 earthquake 6 km ENE of P?hala, Hawaii at 21:19 UTC. In the 72 hours after this event, the USGS recorded 3 smaller earthquakes within 20 km, consistent with an ongoing aftershock sequence rooted here. See the M3.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 21:15:39 UTC | 3.7ml | 1 km S of Niederau, Austria 47.433°, 12.083° | 10.0 km | 20 | - | - | ✓ Reviewed | USGS → |
Reports of a magnitude 3.7 earthquake 1 km S of Niederau, Austria came in on August 16, 2021 at 21:15 UTC. The event was offshore. See the M3.7 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 21:14:04 UTC | 4.7mb | South Sandwich Islands region -58.597°, -25.165° | 35.0 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 4.7 seismic event took place in the South Sandwich Islands region on August 16, 2021 at 21:14 UTC. See the M4.7 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 20:51:57 UTC | 2.1ml | 32 km S of Port Angeles East, Washington 47.817°, -123.349° | 39.7 km | - | - | - | ✓ Reviewed | USGS → |
Reports of a magnitude 2.1 earthquake 32 km S of Port Angeles East, Washington came in on August 16, 2021 at 20:51 UTC. The event was offshore. See the M2.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 20:50:34 UTC | 5.5mww | South Sandwich Islands region -60.248°, -24.928° | 10.0 km | - | II | green | ✓ Reviewed | USGS → |
On August 16, 2021, worldwide seismic activity registered a magnitude 5.5 earthquake in the South Sandwich Islands region at 20:50 UTC. The USGS PAGER system assigned a green alert level for this event, signalling no significant casualties or damage expected. See the M5.5 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 20:49:48 UTC | 4.5mb | South Sandwich Islands region -58.621°, -23.748° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 4.5 earthquake was recorded in the South Sandwich Islands region on August 16, 2021 at 20:49 UTC. Coming 9 hours after a magnitude 5.0 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. See the M4.5 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 20:34:54 UTC | 2.8ml | 69 km ESE of Denali National Park, Alaska 63.212°, -150.533° | 118.1 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 2.8 seismic event took place 69 km ESE of Denali National Park, Alaska on August 16, 2021 at 20:34 UTC. See the M2.8 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 20:29:14 UTC | 4.6mb | South Sandwich Islands region -58.506°, -23.250° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 4.6 earthquake in the South Sandwich Islands region at 20:29 UTC on August 16, 2021. This event falls inside the aftershock decay of a nearby magnitude 6.9 earthquake that occurred about 9 hours earlier. See the M4.6 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 20:28:02 UTC | 4.7mb | South Sandwich Islands region -57.329°, -25.432° | 35.0 km | - | - | - | ✓ Reviewed | USGS → |
August 16, 2021 brought a magnitude 4.7 earthquake in the South Sandwich Islands region, logged at 20:28 UTC. See the M4.7 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 20:16:52 UTC | 4.2mb | 246 km W of Haveluloto, Tonga -21.109°, -177.583° | 517.8 km | - | - | - | ✓ Reviewed | USGS → |
This magnitude 4.2 event was detected 246 km W of Haveluloto, Tonga on August 16, 2021, with origin time 20:16 UTC. This deep-focus earthquake originated far below the brittle crust, deep inside the mantle. See the M4.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 20:11:23 UTC | 4.6mb | South Sandwich Islands region -57.829°, -24.157° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
This magnitude 4.6 event was detected in the South Sandwich Islands region on August 16, 2021, with origin time 20:11 UTC. Coming 6 hours after a magnitude 5.0 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. See the M4.6 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-16 2021-08-16 19:59:41 UTC | 2.5md | 12km ESE of Angwin, CA 38.548°, -122.313° | -0.2 km | 5 | - | - | ✓ Reviewed | USGS → |
August 16, 2021 brought a magnitude 2.5 earthquake 12km ESE of Angwin, CA, logged at 19:59 UTC. This very shallow event was close enough to the surface that even modest magnitudes can produce significant local shaking. See the M2.5 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 August 16, 2021. Data includes all events of magnitude 1.0 or greater. Past earthquake data is considered final after review by USGS seismologists.