Stanford scientists have created the first global map of the rare continental mantle earthquakes that occur beneath the Earth's thin crust in the mantle.[1] These earthquakes occur worldwide, but are regionally clustered especially in the Himalayas of South Asia and the Bering Strait between Asia and North America.[1][2] Using seismic wave and crustal thickness analysis, the researchers identified 459 continental mantle earthquakes since 1990 from an initial set of more than 46,000 earthquakes.[1] The number is conservative and could be higher with the expansion of seismic networks in remote areas such as the Tibetan Plateau.[1] Most continental earthquakes have epicenters at depths of 10 to 30 km, which is above the Moho boundary in the crust.[1] This method uses regional seismic waves and their amplitudes compared to crustal earthquakes.[2] Mantle earthquakes occur in regions with crustal earthquakes, but under a wider range of tectonic and thermal conditions.[2] The study will provide insight into the crust-mantle boundary and the behavior of the upper mantle.[1]