Moderate mag. 5.8 earthquake - Tonga: South of Fiji Islands on Tuesday, 17 August 2021 at 17:24 (GMT) - information
Moderate mag. 5.8 earthquake - South Pacific Ocean, 291 km southwest of Nukalofa, Nuku'alofa, Tongatapu, on Wednesday, Aug 18, 2021 at 6:24 am (GMT +13)
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Moderate magnitude 5.8 earthquake at 184 km depth
17 Aug 17:34 UTC: First to report: GFZ after 10 minutes.
17 Aug 17:36: Magnitude recalculated from 5.9 to 6.0. Hypocenter depth recalculated from 185.0 to 184.0 km (from 115 to 114 mi). Epicenter location corrected by 7.2 km (4.4 mi) towards W.
17 Aug 18:08: Magnitude recalculated from 6.0 to 5.8.
17 Aug 17:36: Magnitude recalculated from 5.9 to 6.0. Hypocenter depth recalculated from 185.0 to 184.0 km (from 115 to 114 mi). Epicenter location corrected by 7.2 km (4.4 mi) towards W.
17 Aug 18:08: Magnitude recalculated from 6.0 to 5.8.
Earthquake details
| Date & time | Aug 17, 2021 17:24:52 UTC - |
| Local time at epicenter | Wednesday, Aug 18, 2021 at 6:24 am (GMT +13) |
| Status | Confirmed |
| Magnitude | 5.8 |
| Depth | 184.0 km |
| Epicenter latitude / longitude | 23.12°S / 177.04°W  (South Pacific Ocean, Tonga) |
| Antipode | 23.12°N / 2.96°E |
| Shaking intensity | Light shaking near epicenter |
| Felt | 0 reports |
| Primary data source | GFZ (German Research Centre for Geosciences) |
| Nearest volcano | Unnamed 24.8°S/177.02°W (187 km / 116 mi) |
| Nearby towns and cities | 289 km (179 mi) SW of Haveluloto (pop: 3,420) | Show on map | Quakes nearby 291 km (181 mi) SW of Nukalofa (Nuku'alofa) (pop: 22,400) | Show on map | Quakes nearby 291 km (181 mi) SW of Nuku‘alofa (pop: 22,400) | Show on map | Quakes nearby 293 km (182 mi) SW of ‘Ohonua (Ohonua) (pop: 1,240) | Show on map | Quakes nearby 300 km (187 mi) SW of Kolonga (pop: 1,100) | Show on map | Quakes nearby 461 km (286 mi) SW of Bangai (Pangai) (pop: 1,740) | Show on map | Quakes nearby 289 km (179 mi) SW of Amsterdam Island (pop: 75,000) | Show on map | Quakes nearby |
| Weather at epicenter at time of quake | Light Rain  21°C (70 F), humidity: 79%, wind: 8 m/s (16 kts) from E |
| Estimated seismic energy released | 3.2 x 1013 joules (8.78 gigawatt hours, equivalent to 7558 tons of TNT or 0.5 atomic bombs!) | about seismic energy |
Data for the same earthquake reported by different agencies
Info: The more agencies report about the same quake and post similar data, the more confidence you can have in the data. It takes normally up to a few hours until earthquake parameters are calculated with near-optimum precision.
| Mag. | Depth | Location | Source |
| 5.8 | 184 km | Tonga: South of Fiji Islands | GFZ |
| 5.8 | 139 km | Tonga: SOUTH OF FIJI ISLANDS | EMSC |
| 5.8 | 182 km | Tonga: South of Fiji Islands | BMKG |
| 5.7 | 171 km | Tonga: Near North Shore | RENASS |
| 5.8 | 157 km | 285 Km SW of Vaini, Tonga | USGS |
| 5.8 | 171 km | Tonga: South of Fiji Islands | GeoAu |
User reports for this quake
User reports estimate the perceived ground shaking intensity according to the MMI (Modified Mercalli Intensity) scale.
Aftershocks
[More info]
Recorded aftershocks, latest first (2 quakes)
Date and time | Mag Depth | Location | Details |
| Sep 17, 2021 16:42 47 weeks ago | 4.3 151 km | South Pacific Ocean, 252 km SW of Nukalofa, Nuku'alofa, Tongatapu | More |
| Aug 19, 2021 10:24 51 weeks ago | 4.8 180 km | South Pacific Ocean, Tonga | More |
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