Deep Low‐Frequency Earthquake Reveals Unsteady Fluid Flow Beneath Tengchong Volcano Field in Southeast Tibet

Abstract

Abstract Deep low‐frequency earthquakes (DLFE) are observed beneath volcanoes worldwide but are limited to island arc volcanoes, hotspot volcanoes, and rift zones. Here we show DLFEs in the Tengchong Volcano Field, southeast Tibet, located ∼300 km from the Indo‐Burma volcanic arc, by analyzing a 12‐year continuous seismic data set. The earthquakes were at a depth of ∼12 km, near the sidewall of the magma body detected by the magnetotelluric survey. The features of isotropic focal mechanism, episodic occurrence, and possible non‐power‐law scaling, with no detectable geodetic deformation, as well as the petrological signatures of the Holocene eruption product, suggest that the earthquakes were likely associated with the weak intermittent magma flows near the magma body. This finding may demonstrate the existence of unsteady magmatic processes in the margin of the Indo‐Eurasia collision zone, which could indicate unneglectable volcanic hazards, underestimated geothermal resources, and mineralization processes in similar regions.

Keywords

• deep low‐frequency earthquake
• Tengchong volcanic field
• continental collision zone
• unsteady fluid dynamics