Coseismic displacements on Ischia island, real-time GPS positioning constraints on earthquake source location

Abstract

We use GNSS data to simulate the early seismic source location of a Mw 3.9 event occurred in the island of Ischia, Italy. The study suggests that real-time GNSS data can support the seismic location system in the early stage of the emergency phase. We demonstrate that this very shallow earthquake, triggered significant displacements at a few stations in less than half an hour. Using exclusively GPS data, the first location of the hypocenter was possible with a latency of only 20 minutes. Early upgrades of the offset field in the first two hours confirm the source location confined within 1-2 km in the horizontal plane and less than 1 km depth.