M5.9 Earthquake 39 km S of Mount Buller, Australia — September 21, 2021
2021-09-21 23:15:53 UTC (2021-09-21) · approx. 9:15 AM UTC+10 local
Felt by 5,846 people across a wide area. Maximum shaking intensity MMI 7.1 (severe).
On September 21, 2021 at 23:15 UTC, a magnitude 5.9 shallow crustal earthquake struck 39 km S of Mount Buller, Australia, at a depth of 12.0 km and coordinates -37.4920°, 146.3534°. The earthquake was reported felt by 5,846 peopleacross a wide area, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 7.1 (severe). The USGS PAGER system issued a yellow alert level for this event, indicating local impact possible. The nearest populated place is Traralgon (population 21,960).
Physical scale: An earthquake of magnitude 5.9 releases seismic energy equivalent to roughly 11 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 7.1 km — a useful intuition for the size of the slip patch on the fault.
Nearest Populated Places
What the Shaking Felt Like
At MMI 7.1 (severe), people in the most strongly affected areas would have experienced: Very strong shaking. Difficult to stand. Damage to weak structures; slight damage to well-built structures. Furniture broken. Fallen plaster and loose bricks.
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 5,846 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Population exposure (USGS PAGER)
Estimated population that experienced each level of shaking. Based on the USGS PAGER rapid impact assessment, which combines ShakeMap output with global population grids.
| Shaking intensity (MMI) | Description | Population exposed |
|---|---|---|
| MMI 3 | weak | 6,373,297 |
| MMI 4 | light | 6,686,686 |
| MMI 5 | moderate | 853,579 |
| MMI 6 | strong | 16,834 |
| MMI 7 | very strong | 111 |
Earthquake Details
146.3534°E
Technical Information
Common Questions
How strong was the magnitude 5.9 earthquake near Mount Buller, Australia?
The magnitude 5.9 earthquake that struck 39 km S of Mount Buller, Australia on September 21, 2021 at 23:15 UTC had a depth of 12.0 km. It was felt by 5,846 people with maximum shaking intensity of MMI 7.1 (severe). For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at -37.4920°, 146.3534°, which is 39 km S of Mount Buller, Australia. The nearest populated place is Traralgon (population 21,960).
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.9 earthquakes can continue for days to weeks and gradually diminish over time.
Authoritative source: USGS event page (event ID: us7000fd9v). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, September 21, 2021). M5.9 Earthquake 39 km S of Mount Buller, Australia — September 21, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000fd9v/