2.1

M2.1 Earthquake 20 km S of Naalehu, HawaiiOctober 10, 2021

2021-10-10 22:28:30 UTC (2021-10-10) · approx. 12:28 PM UTC-10 local

MagnitudeM2.1(md)
Time22:28 UTC12:28 PM UTC-10
Depth34.0 kmshallow crustal
Coordinates18.883°, -155.546°
Felt by2DYFI responses
Status✓ Reviewed by USGS

On October 10, 2021 at 22:28 UTC, a magnitude 2.1 shallow crustal earthquake struck 20 km S of Naalehu, Hawaii, at a depth of 34.0 km and coordinates 18.8832°, -155.5457°.

Physical scale: An earthquake of magnitude 2.1 releases seismic energy equivalent to roughly 22.0 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 17 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 18.88°, -155.55°

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 2 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.

USGS DYFI community-reported intensity map for the M2.1 earthquake near 20 km S of Naalehu, Hawaii

Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report

Earthquake Details

Magnitude
2.1 md
Depth
34.0 km
shallow crustal
Location
18.8832°N
-155.5457°E
Felt Reports
2
DYFI responses
Community Intensity
0.0
CDI from reports

Technical Information

Event ID
hv72748847
Event Type
earthquake
Status
✓ Reviewed
Significance
68
Stations Used
28
Azimuthal Gap
273.0°
RMS Residual
0.12 sec
Last Updated
2021-10-14 03:18:22 UTC

Common Questions

How strong was the magnitude 2.1 earthquake near Naalehu, Hawaii?

The magnitude 2.1 earthquake that struck 20 km S of Naalehu, Hawaii on October 10, 2021 at 22:28 UTC had a depth of 34.0 km. For context, this was a minor earthquake typically detected only by instruments.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 2.1 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 2.1 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: hv72748847). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, October 10, 2021). M2.1 Earthquake 20 km S of Naalehu, HawaiiOctober 10, 2021. Retrieved October 14, 2021 from https://www.earthquaketracker.org/earthquakes/event/hv72748847/