资源环境科技发展态势分析平台

On 8 September 2017, a great (M-w 8.2) normal faulting earthquake ruptured within the subducting Cocos Plate similar to 70 km landward from the Middle American Trench beneath the Tehuantepec gap. Iterative inversion and modeling of teleseismic and tsunami data and prediction of GPS displacements indicate that the steeply dipping rupture extended similar to 180 km to the northwest along strike toward the Oaxaca coast and from similar to 30 to 70 km in depth, with peak slip of similar to 13 m. The rupture likely broke through the entire lithosphere of the young subducted slab in response to downdip slab pull. The plate boundary region between the trench and the fault intersection with the megathrust appears to be frictionally coupled, influencing location of the detachment. Comparisons of the broadband body wave magnitude (m(B)) and moment-scaled radiated energy (E-R/M-0) establish that intraslab earthquakes tend to be more energetic than interplate events, accounting for strong ground shaking observed for the 2017 event.