Magnitude 6.6 Earthquake Strikes Northern Mid-Atlantic Ridge, USGS Issues Green Alert
On March 21, 2026, a magnitude 6.6 earthquake struck the northern Mid-Atlantic Ridge in the North Atlantic Ocean. The U.S. Geological Survey (USGS) event page (event ID us6000si5l) recorded the quake at 12:16:46 UTC on March 21, at a depth of about 10 km, centered at 23.86 degrees north latitude and 45.80 degrees west longitude along the mid-ocean ridge, far from any land.
The USGS PAGER loss-estimation system issued a green alert for the earthquake, indicating a low likelihood of casualties and damage; there is no significant population center within 400 km of the epicenter. The Pacific Tsunami Warning Center issued a tsunami information bulletin for the event, and USGS reported no casualties or property damage.
The Mid-Atlantic Ridge is the submarine mountain range and plate boundary running the length of the Atlantic Ocean, and earthquakes along it mostly occur in waters far from land. At magnitude 6.6, this was one of the stronger undersea earthquakes worldwide that month.
Related: Magnitude 7.5 Deep Earthquake West of Tonga Is the Strongest Worldwide So Far in 2026
Source: U.S. Geological Survey
Published by GSM · USA (original Chinese edition)
Photo: 图：位于华盛顿的美国内政部主内政大楼外景，USGS 隶属内政部，这次北大西洋中脊6.6级地震由该局测定发布。ajay_suresh 摄，CC BY 4.0，经 Wikimedia Commons。 / Photo: The U.S. Department of the Interior's Main Interior Building in Washington; the USGS, which measured and reported this magnitude 6.6 Mid-Atlantic Ridge earthquake, is part of the Interior Department. Photo by ajay_suresh, CC BY 4.0, via Wikimedia Commons.
