First-ever map of mantle earthquakes expands scientific understanding

Stanford researchers published the first global map of continental mantle earthquakes in Science, showing regional clusters such as the Himalayas and the Bering Strait.

Stanford researchers have produced the first global map of continental mantle earthquakes. The study was published Feb. 5 in Science. These rare earthquakes originate in the mantle, below the crust, and are generally too deep to cause much shaking at Earth's surface. The map shows that mantle earthquakes occur worldwide but are regionally clustered, notably in the Himalayas and the Bering Strait. Researchers say the new dataset can help probe earthquake mechanics and the crust–mantle boundary. Key findings: - The paper presents the first-ever global map of continental mantle earthquakes. - The study was published Feb. 5 in Science and was led by Stanford researchers including Shiqi (Axel) Wang and Simon Klemperer. - Mantle earthquakes are geographically clustered, especially in the Himalayas and the Bering Strait south of the Arctic Circle. - The mantle is a warm, semisolid layer about 1,800 miles thick, separated from the crust by the Mohorovičić discontinuity, also called the Moho. - Mantle earthquakes are much less frequent than crustal quakes, perhaps roughly 100 times less often, and have been difficult to identify previously because of limited data. Summary: The map provides a new dataset that researchers expect will deepen understanding of how and where earthquakes originate and of upper mantle structure. The authors say it will enable further studies of how these rare mantle quakes initiate and of conditions at the crust–mantle boundary. The findings could broaden scientific insight into factors that influence more common, shallower earthquakes.