| Summary: | 碩士 === 國立交通大學 === 土木工程系所 === 105 === Earthquake Early Warning [EEW] has become one of the forefront researches in seismology and signal processing in recent years. The key reason for this popularity is related to the great deal of application this research has in present day society since earthquakes are still responsible for a large percentage of property damages and lives lost. At present it is still beyond our understanding to predict an earthquake before it occurs, however EEW is the closest option we have to help save lives and reduce losses.
Earthquake early warning hence is an important tool for modern day earthquake prone societies like Taiwan, Japan and the US. Lots of resources are being spent on the development of different types of EEW system networks of varying types. Current systems may be operated by both government of private sectors. Most if not all government systems are mainly based on traditional seismic stations positions at different geographical locations, these sensors alert distant sensors and main observation station when an event is triggered, giving warning of the incoming propagation of an earthquake wave. More advanced methods being develop utilized by private companies and researchers use smartphones as sensors with installed applications that feeds back acceleration data of the smartphone to a centralized network that triggers when an earthquake event is detected.
The latter of these methods are the focus of this research document. This is the first step in a multi-phase development a smartphone based seismic detection network using MATLAB in Taiwan. This initial step is to show that a smartphone can be used to measure earthquake intensity and issue an alert to a single user using the MATLAB platform. The smart phone used in this research is a Samsung Galaxy S6 device. Other tools used includes installation of the MATLAB Mobile app on the smartphone, a computer with MATLAB software and a router. Tests were performed at the National Chiao Tung University Structural Engineering Building and at the National Center for Research on Earthquake Engineering in Taiwan.
One of the main goals in this research was to investigate alternative methods to trigger an earthquake alarm apart from using the more popular STA/LTA algorithm however the main objective was to be able to create a MATLAB script that can alert a single user when an earthquake is occurring. To do this an earthquake event was simulated by placing the smartphone on a shaking table while running the written MATLAB code. The result of which allowed the researcher to remotely detect an earthquake motion and receive and alert that an earthquake event was being propagated. Final results showed PGA (Peak Ground Acceleration) values measured were within eighty-five (85%) of input signal’s peak acceleration amplitudes. Reaction time from the start of the event to reporting of an event is estimated to be around ten (10) seconds on average. On this basis one can develop future mechanisms to create a smartphone seismic network locally which can be regionally applied.
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