EarthBrowserEarthquake · Friday, October 23, 2026
Magnitude 4.3 earthquake 289 km W of Houma, Tonga
A magnitude 4.3 (light) earthquake struck 289 km W of Houma, Tonga on Friday, October 23, 2026 at , at a depth of 463 km (deep).
- Magnitude
- 4.3Light
- Depth
- 463km · deep
- Time
- Epicenter
- 20.89° S
178.07° W - Aftershocks so far
- 3within 250 km
- Largest aftershock
- 6.1M
17 days ago · USGS id us6000u4ac · last revised
The full globe opens the 3D cross-section: the hypocenter at depth, the plate boundary and subducting slab where there is one, the aftershock sequence as it grows, and the sea floor around an offshore epicenter.
What a magnitude 4.3 means
Light earthquakes are widely felt near the epicenter, rattling windows and shelves, but rarely cause damage.
A magnitude 4.3 releases about 32 times the seismic energy of a magnitude 3.3, roughly the energy of 43 tonnes of TNT. Magnitude measures the energy released at the source; how hard the ground shook at any one place depends on distance, depth and local geology, and is reported separately as intensity.
Deep earthquakes (below 300 km) happen far down in a sinking slab of oceanic plate. They are felt over very large distances but rarely cause damage, and they do not generate tsunamis.
Nearby earthquakes and aftershocks
This event is part of a sequence: a larger magnitude 6.1 struck 68 km away on Nov 5, 17:21 UTC, so this is most likely one of its foreshocks.
| Time (UTC) | Magnitude | Depth | Distance | Location |
|---|---|---|---|---|
| 6.1 | 541 km | 68 km | Fiji region | |
| 4.6 | 556 km | 189 km | Fiji region | |
| 4.4 | 576 km | 195 km | Fiji region | |
| before | 4.2 | 625 km | 118 km | Fiji region |
| before | 4.5 | 552 km | 61 km | Fiji region |
| before | 5.9 | 585 km | 74 km | Fiji region |
| before | 4.6 | 513 km | 70 km | 260 km WNW of Houma, Tonga |
| before | 4.6 | 560 km | 119 km | 268 km WNW of Houma, Tonga |
| before | 4.4 | 638 km | 122 km | Fiji region |
| before | 4.7 | 573 km | 50 km | Fiji region |
Frequently asked questions
How is earthquake magnitude measured?
Modern magnitudes are moment magnitudes (Mw), computed from the seismic moment: the area of the fault that slipped, how far it slipped and the rigidity of the rock. Each whole step up the scale is about 32 times more energy, so a magnitude 7 releases roughly a thousand times the energy of a magnitude 5.
What is the difference between magnitude and intensity?
Magnitude is one number for the whole earthquake, describing the energy released at the source. Intensity describes the shaking at a particular place, on the Modified Mercalli scale from I (not felt) to X+ (extreme), and falls off with distance from the epicenter.
What is an aftershock?
An aftershock is a smaller earthquake in the same area after a larger one, as the crust around the ruptured fault adjusts to the new stresses. They are most frequent in the first hours and days and fade over weeks to months, though a large mainshock can produce aftershocks for years.
Why do the magnitude and location change?
The first solution uses the nearest stations only. As recordings arrive from more seismographs around the world, USGS revises the magnitude, depth and epicenter, sometimes several times in the first hours. This page reflects the latest revision.
Where does this earthquake data come from?
From the U.S. Geological Survey’s real-time earthquake feeds, which combine the USGS National Earthquake Information Center with regional seismic networks worldwide. EarthBrowser ingests the feed every minute.