ANALYSIS OF SMARTPHONE EARTHQUAKE EARLY WARNING NETWORKS IN CHILE AND COSTA RICA

Abstract

Seismometers and continuous GNSS stations can be used to detect the ground motion from an earthquake, and issue an alarm before strong ground shaking reaches a population center. Although Earthquake Early Warning (EEW) systems have been around since 1991, they have been implemented in only a few countries due to the large costs associated with installing, maintaining, and monitoring them. The accelerometers and GNSS chips inside modern smartphones can detect the shaking and displacements from large earthquakes, and so smartphones can augment or even replace the high cost scientific grade instruments that are traditionally used in EEW networks to help lower costs, and make these systems more affordable for developing countries. Our team has developed an EEW system that uses smartphones for its sensors, and has installed networks in Chile and Costa Rica. Here we analyze the performance of the internal and external GNSS chips used in our system while installed in several building types, the latencies associated with the message transmission time, and the performance of our Costa Rica EEW system in a real-world application by simulating the 2012 Nicoya Earthquake. Our analysis suggests that the external UBLOX GNSS chip used in our system should be able to detect the displacements from large earthquakes, and that our network latency isn’t large enough to significantly reduce our ability to issue timely warnings.