NUKU’ALOFA, July 6 — A magnitude 5.1 earthquake struck 211 km ESE of Hihifo, Tonga, at 14:43 UTC on Monday, according to the U.S. Geological Survey. The quake occurred at a depth of 10 km, placing it in the shallow category. Seismologists classify earthquakes less than 70 km deep as shallow events, which typically produce stronger shaking at the surface than deeper quakes of the same magnitude.
No tsunami warning was issued following the event, the USGS confirmed. The USGS detected the earthquake through its real-time global seismic monitoring network.
The agency’s data places the epicenter in a region of the South Pacific known for frequent tectonic activity. The record shows this is not an isolated event. At least 500 earthquakes of magnitude 5.0 or greater have been recorded within about 300 km of this area over the past two decades.
The strongest during that period was a magnitude 8.1 earthquake in 2009. A magnitude 5.1 earthquake is classified as moderate.
According to the USGS, such events are capable of causing minor to moderate damage near the epicenter. The shallow depth of this particular quake increases the likelihood that shaking was felt more intensely by anyone in the immediate vicinity. Seismologists note that aftershocks are common following an earthquake of this size.
The record shows that aftershocks may continue for days or even weeks after the main event. People in the affected area are generally advised to be prepared for further shaking. The Tonga region sits along the Pacific Ring of Fire, a zone of intense seismic and volcanic activity.
The area has a long history of significant earthquakes. The 2009 magnitude 8.1 event remains the largest recorded within the 300 km radius over the past two decades.
At this time, there are no reports of damage or casualties. The USGS continues to monitor the region for any subsequent seismic activity.
