Earthquakes on August 23, 2021
387
EARTHQUAKES on August 23, 2021
24-hour UTC period · USGS data
LARGEST: M5.2 — South Sandwich Islands region
10 km deep
Elevated activitycompared to daily average (~250/day)
Magnitude Breakdown
M5.0+
4
M4.0–4.9
56
M3.0–3.9
8
M2.0–2.9
59
M1.0–1.9
260
Activity Summary
387
Total earthquakes
~250
Daily average
Elevated
Activity level
4
M5.0+ events
Significant Earthquakes (M4.5+)
5.2
South Sandwich Islands region
06:02 UTC · 10.0 km deep
5.1
South Sandwich Islands region
03:05 UTC · 10.0 km deep
5.1
South Sandwich Islands region
00:56 UTC · 10.0 km deep
5.0
South Sandwich Islands region
14:28 UTC · 10.0 km deep
4.9
136 km ESE of Iquique, Chile
21:02 UTC · 103.3 km deep
Felt by 9
4.9
218 km SW of Waingapu, Indonesia
08:40 UTC · 10.0 km deep
4.8
Kermadec Islands, New Zealand
19:43 UTC · 178.5 km deep
4.8
65 km E of Yilan, Taiwan
10:56 UTC · 10.0 km deep
Earthquake Map — August 23, 2021
All Earthquakes — August 23, 2021
Showing 30 of 127 (filtered from 387)
(Filtered to M2.0+. Change the magnitude filter to see smaller events.)
| Time ↓ | Mag ↕ | Location ↕ | Depth ↕ | Felt ↕ | MMI | Alert | Status | Details |
|---|---|---|---|---|---|---|---|---|
2021-08-23 2021-08-23 23:49:36 UTC | 4.3mb | 150 km E of Yamada, Japan 39.309°, 143.679° | 19.7 km | - | - | - | ✓ Reviewed | USGS → |
Reports of a magnitude 4.3 earthquake 150 km E of Yamada, Japan came in on August 23, 2021 at 23:49 UTC. The event was offshore. See the M4.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 23:14:14 UTC | 4.3mb | Mariana Islands region 21.753°, 142.998° | 295.1 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 4.3 seismic event took place in the Mariana Islands region on August 23, 2021 at 23:14 UTC. See the M4.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 22:51:52 UTC | 2.4ml | 11km W of Calipatria, CA 33.144°, -115.631° | 7.9 km | - | - | - | ✓ Reviewed | USGS → |
On August 23, 2021, worldwide seismic activity registered a magnitude 2.4 earthquake 11km W of Calipatria, CA at 22:51 UTC. Coming 8 hours after a magnitude 4.0 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. The event was offshore. See the M2.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 22:51:27 UTC | 2.4md | 28km SSW of Smith Valley, NV 38.546°, -119.457° | 3.9 km | 1 | - | - | ✓ Reviewed | USGS → |
August 23, 2021 brought a magnitude 2.4 earthquake 28km SSW of Smith Valley, NV, logged at 22:51 UTC. This event falls inside the aftershock decay of a nearby magnitude 3.0 earthquake that occurred about 15 hours earlier. This very shallow event was close enough to the surface that even modest magnitudes can produce significant local shaking. See the M2.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 22:50:38 UTC | 2.5ml | 9 km NNE of Hamilton, Washington 48.600°, -121.957° | 2.5 km | 8 | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 2.5 earthquake 9 km NNE of Hamilton, Washington at 22:50 UTC on August 23, 2021. It arrived roughly 1 hours after a larger magnitude 2.8 mainshock in the same 20 km area, placing it within the typical aftershock window. 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. | ||||||||
2021-08-23 2021-08-23 22:27:26 UTC | 2.8ml | 9 km NNE of Hamilton, Washington 48.606°, -121.959° | 2.4 km | 37 | II | - | ✓ Reviewed | USGS → |
A magnitude 2.8 earthquake was recorded 9 km NNE of Hamilton, Washington on August 23, 2021 at 22:27 UTC. In the 72 hours after this event, the USGS recorded 4 smaller earthquakes within 20 km, consistent with an ongoing aftershock sequence rooted here. See the M2.8 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 22:18:58 UTC | 3.0md | 5 km SSE of Guánica, Puerto Rico 17.924°, -66.885° | 8.0 km | - | - | - | ✓ Reviewed | USGS → |
This magnitude 3.0 event was detected 5 km SSE of Guánica, Puerto Rico on August 23, 2021, with origin time 22:18 UTC. It arrived roughly 15 hours after a larger magnitude 3.4 mainshock in the same 20 km area, placing it within the typical aftershock window. See the M3.0 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 22:15:27 UTC | 2.1ml | Alaska Peninsula 58.856°, -154.413° | 122.6 km | - | - | - | ✓ Reviewed | USGS → |
August 23, 2021 brought a magnitude 2.1 earthquake near Alaska Peninsula, logged at 22:15 UTC. This event falls inside the aftershock decay of a nearby magnitude 2.2 earthquake that occurred about 19 hours earlier. See the M2.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 22:03:11 UTC | 2.2ml | 7 km ENE of P?hala, Hawaii 19.223°, -155.408° | 34.2 km | - | - | - | Auto | USGS → |
On August 23, 2021 at 22:03 UTC, a magnitude 2.2 earthquake struck 7 km ENE of P?hala, Hawaii. This event falls inside the aftershock decay of a nearby magnitude 2.4 earthquake that occurred about 14 hours earlier. See the M2.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 21:55:43 UTC | 2.9ml | 11km W of Calipatria, CA 33.143°, -115.631° | 9.4 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 2.9 seismic event took place 11km W of Calipatria, CA on August 23, 2021 at 21:55 UTC. Coming 7 hours after a magnitude 4.0 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. The event was offshore. See the M2.9 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 21:18:50 UTC | 4.2mb | Izu Islands, Japan region 31.527°, 142.694° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 4.2 earthquake was recorded in the Izu Islands, Japan region on August 23, 2021 at 21:18 UTC. See the M4.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 21:05:43 UTC | 2.1ml | 44km NE of Holtville, CA 33.062°, -115.011° | -0.2 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 2.1 seismic event took place 44km NE of Holtville, CA on August 23, 2021 at 21:05 UTC. This very shallow event was close enough to the surface that even modest magnitudes can produce significant local shaking. See the M2.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 21:02:24 UTC | 4.9mb | 136 km ESE of Iquique, Chile -20.900°, -69.059° | 103.3 km | 9 | - | - | ✓ Reviewed | USGS → |
At 21:02 UTC on August 23, 2021, a magnitude 4.9 tremor occurred 136 km ESE of Iquique, Chile. See the M4.9 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 20:59:53 UTC | 4.7mb | 34 km WNW of Sibolga, Indonesia 1.904°, 98.516° | 80.9 km | - | - | - | ✓ Reviewed | USGS → |
On August 23, 2021 at 20:59 UTC, a magnitude 4.7 earthquake struck 34 km WNW of Sibolga, Indonesia. See the M4.7 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 20:49:02 UTC | 4.4mb | 109 km W of Constitución, Chile -35.521°, -73.591° | 10.0 km | 1 | - | - | ✓ Reviewed | USGS → |
Reports of a magnitude 4.4 earthquake 109 km W of Constitución, Chile came in on August 23, 2021 at 20:49 UTC. The event was offshore. See the M4.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 20:26:05 UTC | 2.3ml | 38 km ENE of McKinney Acres, Texas 32.401°, -102.134° | 10.5 km | - | - | - | ✓ Reviewed | USGS → |
This magnitude 2.3 event was detected 38 km ENE of McKinney Acres, Texas on August 23, 2021, with origin time 20:26 UTC. See the M2.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 20:09:28 UTC | 2.0ml | 163 km SE of Atka, Alaska 51.082°, -172.663° | 20.0 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 2.0 earthquake was recorded 163 km SE of Atka, Alaska on August 23, 2021 at 20:09 UTC. The event was offshore. See the M2.0 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 19:43:50 UTC | 4.8mb | Kermadec Islands, New Zealand -29.753°, -178.562° | 178.5 km | - | - | - | ✓ Reviewed | USGS → |
This magnitude 4.8 event was detected near Kermadec Islands, New Zealand on August 23, 2021, with origin time 19:43 UTC. See the M4.8 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 19:40:54 UTC | 2.4ml | 13 km SSE of Fern Forest, Hawaii 19.352°, -155.094° | 6.3 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 2.4 earthquake 13 km SSE of Fern Forest, Hawaii at 19:40 UTC on August 23, 2021. This event falls inside the aftershock decay of a nearby magnitude 2.6 earthquake that occurred about 4 hours earlier. See the M2.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 19:28:50 UTC | 4.0mb | 247 km ESE of Chiniak, Alaska 56.443°, -148.820° | 10.0 km | - | I | - | ✓ Reviewed | USGS → |
A magnitude 4.0 seismic event took place 247 km ESE of Chiniak, Alaska on August 23, 2021 at 19:28 UTC. See the M4.0 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 19:19:23 UTC | 4.2mb | 79 km SW of Ishigaki, Japan 23.824°, 123.616° | 30.5 km | - | - | - | ✓ Reviewed | USGS → |
Seismographs logged a magnitude 4.2 earthquake 79 km SW of Ishigaki, Japan with origin time 19:19 UTC on August 23, 2021. The event was offshore. See the M4.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 18:52:53 UTC | 2.9ml | 111 km SSE of Sand Point, Alaska 54.429°, -159.773° | 30.5 km | - | - | - | ✓ Reviewed | USGS → |
August 23, 2021 brought a magnitude 2.9 earthquake 111 km SSE of Sand Point, Alaska, logged at 18:52 UTC. See the M2.9 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 18:49:33 UTC | 4.3mb | Kuril Islands 47.267°, 153.099° | 89.8 km | - | - | - | ✓ Reviewed | USGS → |
August 23, 2021 brought a magnitude 4.3 earthquake near Kuril Islands, logged at 18:49 UTC. See the M4.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 18:06:53 UTC | 4.5mb | Macquarie Island region -53.882°, 159.222° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 4.5 earthquake was recorded in the Macquarie Island region on August 23, 2021 at 18:06 UTC. See the M4.5 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 17:33:53 UTC | 2.3ml | 20 km WSW of Stanley, Idaho 44.160°, -115.188° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
Reports of a magnitude 2.3 earthquake 20 km WSW of Stanley, Idaho came in on August 23, 2021 at 17:33 UTC. It arrived roughly 12 hours after a larger magnitude 2.6 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. | ||||||||
2021-08-23 2021-08-23 17:09:04 UTC | 2.2ml | 44 km NW of Toyah, Texas 31.610°, -104.115° | 7.1 km | - | - | - | ✓ Reviewed | USGS → |
At 17:09 UTC on August 23, 2021, a magnitude 2.2 tremor occurred 44 km NW of Toyah, Texas. The event was offshore. See the M2.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 16:49:58 UTC | 2.0md | 2 km SE of P?hala, Hawaii 19.191°, -155.461° | 35.5 km | - | - | - | Auto | USGS → |
This magnitude 2.0 event was detected 2 km SE of P?hala, Hawaii on August 23, 2021, with origin time 16:49 UTC. Coming 8 hours after a magnitude 2.4 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. The event was offshore. See the M2.0 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 16:43:14 UTC | 2.0md | 7 km SSE of P?hala, Hawaii 19.141°, -155.449° | 34.7 km | - | - | - | Auto | USGS → |
Reports of a magnitude 2.0 earthquake 7 km SSE of P?hala, Hawaii came in on August 23, 2021 at 16:43 UTC. It arrived roughly 8 hours after a larger magnitude 2.4 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. | ||||||||
2021-08-23 2021-08-23 16:42:02 UTC | 2.2ml | 254 km ESE of Attu Station, Alaska 52.070°, 176.710° | 142.8 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 2.2 earthquake 254 km ESE of Attu Station, Alaska at 16:42 UTC on August 23, 2021. See the M2.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-23 2021-08-23 16:15:51 UTC | 2.0ml | 11km N of Westmorland, CA 33.132°, -115.639° | 7.7 km | - | - | - | ✓ Reviewed | USGS → |
Seismographs logged a magnitude 2.0 earthquake 11km N of Westmorland, CA with origin time 16:15 UTC on August 23, 2021. This event falls inside the aftershock decay of a nearby magnitude 4.0 earthquake that occurred about 1 hours earlier. The event was offshore. See the M2.0 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 23, 2021. Data includes all events of magnitude 1.0 or greater. Past earthquake data is considered final after review by USGS seismologists.