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Could a Decentralized Onsite Earthquake Early Warning System Help in Mitigating Seismic Risk in North-Eastern Italy? The Case of the Ms 6.5 1976 Friuli Earthquake

Session: Earthquake Early Warning Live in California! Current Status and Challenges I

Type: Oral

Date: 4/23/2021

Presentation Time: 10:30 AM Pacific

Description: 

In May 1976, an earthquake of Ms=6.5 occurred in Friuli (Italy), resulting in 976 deaths, 2,000 injured, and 60,000 homeless. Due to two further shocks that occurred in September 1976, some 40,000 people were displaced to the coast, far away from the epicentral area. It is notable that at the time of the earthquake, only one seismological station was installed in the affected region. The resulting lack of information, combined with a dearth of mitigation planning for responding to such events, lead to a clear picture of the impact of the disaster being available only after a few days.

This region is now covered by nearly 100 seismological and strong motion stations operating in real- time. Furthermore, 54 new average-cost real-time strong motion stations have been recently added, with the aim of improving the density of ground motion observation, and to measure the level of shaking recorded at selected buildings. The final goal is to allow rapid impact estimations to be made in order to improve upon the response of civil protection authorities. Today, considering the higher density seismological network, new efforts in terms of the implementation and testing of earthquake early warning (EEW) systems as a possible tool for mitigating seismic risk are certainly worthwhile.

In this presentation, we show the results obtained by analyzing in playback, and using an algorithm for Decentralized On-Site Earthquake Early Warning (DOSEEW), broad-band synthetic strong motion data calculated at 18 of the stations installed in the region, while considering the magnitude and location of the 1976 Friuli earthquake The analysis shows that the anisotropy of the lead-times is not only related to the finite nature of the source, but also on the slip distribution. A reduction of 10% of injured persons appears to be possible if appropriate mitigating actions are employed. The safety of strategic industrial facilities could benefit from the development of efficient automatic procedures.

Presenting Author: Stefano Parolai

Student Presenter: No

Authors