M7.3 Earthquake 182 km NE of Gisborne, New Zealand — March 4, 2021
2021-03-04 13:27:34 UTC (2021-03-04) · approx. 1:27 AM UTC+12 local
Felt by 154 people across surrounding communities. Maximum shaking intensity MMI 6.5 (very strong).
On March 4, 2021 at 13:27 UTC, a magnitude 7.3 shallow crustal earthquake struck 182 km NE of Gisborne, New Zealand, at a depth of 10.0 km and coordinates -37.4787°, 179.4576°. The earthquake was reported felt by 154 peopleacross surrounding communities, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 6.5 (very strong). The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected.
Physical scale: An earthquake of magnitude 7.3 releases seismic energy equivalent to roughly 1.3 megatons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 66 km — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in New Zealand, a region characterized by the Hikurangi subduction zone in the North Island and the Alpine Fault in the South Island. The nearest mapped fault system is the Alpine Fault. View all earthquakes in New Zealand.
Learn more: Magnitude scale · Aftershock sequences
What the Shaking Felt Like
At MMI 6.5 (very strong), people in the most strongly affected areas would have experienced: Strong shaking felt by everyone. Heavy furniture may move. Books fall from shelves. Plaster and chimneys may crack. Damage is generally slight in well-built structures.
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 154 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 | 2,762,937 |
| MMI 4 | light | 211,562 |
| MMI 5 | moderate | 44,153 |
| MMI 6 | strong | 149 |
Earthquake Details
179.4576°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 7.3 earthquake near Gisborne, New Zealand?
The magnitude 7.3 earthquake that struck 182 km NE of Gisborne, New Zealand on March 4, 2021 at 13:27 UTC had a depth of 10.0 km. It was felt by 154 people with maximum shaking intensity of MMI 6.5 (very strong). For context, this was a strong earthquake capable of causing significant damage.
Where did the earthquake occur?
The earthquake epicenter was located at -37.4787°, 179.4576°, which is 182 km NE of Gisborne, New Zealand. View all earthquakes in New Zealand.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 7.3 earthquakes can continue for months to years and gradually diminish over time.
Has New Zealand had earthquakes this big before?
The largest recorded earthquake in New Zealand was the M8.2 Wairarapa earthquake of January 23, 1855. Today's magnitude 7.3 event is within one magnitude unit of that historical record.
Authoritative source: USGS event page (event ID: us7000dffl). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, March 4, 2021). M7.3 Earthquake 182 km NE of Gisborne, New Zealand — March 4, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000dffl/