Advanced real-time acquisition of the Vrancea earthquake early warning system: Fid-Bau Portal

Advanced real-time acquisition of the Vrancea earthquake early warning system

Mărmureanu, A. / Ionescu, C. / Cioflan, C.O.

Abstract The Vrancea seismogenic zone in Romania represents a peculiar source of seismic hazard, which is a major concern in Europe, especially to neighboring regions of Bulgaria, Serbia and Republic of Moldavia. Earthquakes in the Carpathian–Pannonian region are confined to the crust, except the Vrancea zone, where earthquakes with focal depth down to 200km occur. One of the cities most affected by earthquakes in Europe is Bucharest. Situated at 140–170km distance from Vrancea epicenter zone, Bucharest encountered many damages due to high energy Vrancea intermediate-depth earthquakes; the March 4, 1977 event (M w=7.2) produced the collapse of 36 buildings with 8–12 levels, while more than 150 old buildings were seriously damaged. A dedicated set of applications and a method to rapidly estimate magnitude in 4–5s from detection of P wave in the epicenter were developed. They were tested on all recorded data. The magnitude error for 77.9% of total considered events is in the interval [−0.3, +0.3] magnitude units. This is acceptable taking into account that the magnitude is computed from only 3 stations in a 5s time interval (1s delay is caused by data packing). The ability to rapidly estimate the earthquake magnitude combined with powerful real-time software, as parts of an early warning system, allows us to send earthquake warning to Bucharest in real time, in about 5s after detection in the epicenter. This allows 20–27s warning time to automatically issue preventive actions at the warned facility.