Value of an Earthquake Early Warning System for Central Chile
Abstract
Nearly 70% of the population of Chile is concentrated in its central part together with a significant portion of the productive, communications and power systems. Large events (M around 8 or larger) which could be considered as rupturing the main portion of the seismogenic width have taken place in 1647, 1730, 1822, 1906 and 1985. Clearly, the 1730 event, with an estimated magnitude over 9, stands out as the largest of this sequence. Although the recurrence intervals have been very regular (82±6 years), the rupture lengths differ substantially; the largest one, estimated in more than 500 km, was that associated with the 1730 event.
Exiguous evidence of coastal elevation changes as revealed by witness reports in 1822, and more abundant data for the 1906 event, are used as an indication of possible rupture areas associated with these events. Comparison of the 1906 rupture area with more precise determinations for the 1985 event, allow inferences of a variable mode of rupture in Central Chile. Updated plate locking models obtained by GNSS velocity estimations in the region, together with GNSS derived slip distribution for the 2010 M8.8 Maule, the 2105 M8.3 Illapel, as well as the Valparaiso 2017, M6.9, events are used to interpret the current state of preparation of the next large event in the area. Different source scenarios are studied to test the expected performance of an earthquake early warning system for the capital city that houses nearly 40% of the population of the country. Initial estimates indicate that, for earthquakes taking place along the Nazca-South America interface, warnings could be issued between 15 to 20 s before the stronger phase arrivals. Due to budget restrictions to acquire high-end observational equipment, a prototype system combining good performance with low cost, is currently under development to examine the feasibility of early warning alert systems in this region.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.S24C..03B
- Keywords:
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- 4315 Monitoring;
- forecasting;
- prediction;
- NATURAL HAZARDSDE: 7215 Earthquake source observations;
- SEISMOLOGYDE: 7219 Seismic monitoring and test-ban treaty verification;
- SEISMOLOGYDE: 7294 Seismic instruments and networks;
- SEISMOLOGY