This blog post summarizes a recent seismic event on Hawaii’s Big Island: a magnitude 4.2 earthquake that occurred Sunday morning northwest of Kalaoa.
I’ll explain the basic facts reported by the U.S. Geological Survey (USGS), what the measurements mean for the community, and practical guidance for residents and visitors based on three decades of experience in earthquake science and emergency response.
Quick overview of the quake
The earthquake struck just before 8:30 a.m. local time (2:30 p.m. ET) and briefly shook communities across the island.
Residents in Hilo and other locales reported feeling mild tremors, and local monitoring confirmed that the event produced no immediate injuries or structural damage.
Seismic details and USGS findings
Magnitude and timing: The USGS recorded the event as a magnitude 4.2, which is in the low-to-moderate range for felt earthquakes.
Such quakes commonly cause little to no damage but can be distinctly felt by people in nearby communities.
Epicenter and depth: The epicenter was located approximately 10 miles northwest of Kalaoa at a focal depth of about 28.5 miles beneath the surface.
Depth matters: earthquakes this deep tend to be felt over a wider area but typically produce less intense surface shaking than a shallow event of the same magnitude.
Local impacts: The USGS Shake Map and reports from residents indicate mild shaking in multiple communities, including Hilo.
Authorities reported no tsunami threat, and there are no confirmed reports of injuries or structural damage at the time of this writing.
Ongoing monitoring: Local agencies and the USGS continue to monitor seismicity for potential aftershocks.
Aftershocks are common and the public should remain alert to official advisories.
What this means for residents and infrastructure
For residents, the immediate takeaway is reassurance: this event produced only mild shaking and no reported damage.
Any felt earthquake is a reminder that Hawaii is an active seismic region and preparedness matters.
Preparedness, response, and practical steps
From my 30 years working in earthquake science and preparedness, I recommend simple, proven actions to reduce risk and anxiety after a felt event:
Seismic monitoring is continuous. While a magnitude 4.2 quake typically causes limited effects, it is an important reminder to maintain preparedness and keep emergency plans current.
Local authorities will continue to monitor for aftershocks and provide updates. Residents should follow those advisories and report any damage through official channels.
Here is the source article for this story: Big Island of Hawaii rattled by magnitude 4.2 earthquake