M4.2 Earthquake 8 km ENE of P?hala, Hawaii — August 1, 2020
2020-08-01 20:03:07 UTC (2020-08-01) · approx. 10:03 AM UTC-10 local
Felt by 192 people across surrounding communities. Maximum shaking intensity MMI 4.7 (moderate).
On August 1, 2020 at 20:03 UTC, a magnitude 4.2 shallow crustal earthquake struck 8 km ENE of P?hala, Hawaii, at a depth of 31.7 km and coordinates 19.2398°, -155.4130°. The earthquake was reported felt by 192 peopleacross surrounding communities, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 4.7 (moderate). The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. This earthquake was detected by 63 seismic stations with good location accuracy and was assigned a USGS significance rating of 346, placing it among routine seismic activity. The nearest populated place is Pahala (population 1,356).
Physical scale: An earthquake of magnitude 4.2 releases seismic energy equivalent to roughly 31 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 484 m — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in Hawaii, a region characterized by intraplate volcanic activity over the Hawaiian mantle plume hotspot, with seismicity driven by magma intrusion and flank instability. View all earthquakes in Hawaii.
Learn more: Magnitude scale · Aftershock sequences
Nearest Populated Places
What the Shaking Felt Like
At MMI 4.7 (moderate), people in the most strongly affected areas would have experienced: Mild shaking, similar to a passing truck. Hanging objects swing. Glasses and dishes may rattle. Not commonly felt outdoors.
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 192 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 | 124,557 |
| MMI 4 | light | 1,157 |
| MMI 5 | moderate | 7 |
Earthquake Details
-155.4130°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.2 earthquake near P?hala, Hawaii?
The magnitude 4.2 earthquake that struck 8 km ENE of P?hala, Hawaii on August 1, 2020 at 20:03 UTC had a depth of 31.7 km. It was felt by 192 people with maximum shaking intensity of MMI 4.7 (moderate). For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 19.2398°, -155.4130°, which is 8 km ENE of P?hala, Hawaii. The nearest populated place is Pahala (population 1,356). View all earthquakes in Hawaii.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.2 earthquakes can continue for several days and gradually diminish over time.
Has Hawaii had earthquakes this big before?
The largest recorded earthquake in Hawaii was the M7.9 Ka'u District earthquake of April 2, 1868. Today's magnitude 4.2 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: hv72070977). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2020, August 1, 2020). M4.2 Earthquake 8 km ENE of P?hala, Hawaii — August 1, 2020. Retrieved February 24, 2021 from https://www.earthquaketracker.org/earthquakes/event/hv72070977/