P-wave Arrival Detection based on Signal Cross-Correlation for Earthquake Localization

• Main Authors: Ping-yao Liao, 廖柄堯
• Other Authors: Tai-Lin Chin
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/33424889985978148459

碩士 === 國立臺灣科技大學 === 資訊工程系 === 101 === Since old days, Taiwan has been always threaten by the large, destructive earthquakes as a result of the geographical position between the Philippine Sea Plate and Eurasian Plate. When the earthquake occurred people always suffered from the great damage and the loss of lives after the earthquake. If people can predict the occurrence of the earthquake, people can save the property and lives from the disaster. The earthquake is always affected by many factors such as the geological configuration. Even many research on predicting earthquake, there is not the correct and precise predicting result on practical application up to now. Recently most the research focus on the earthquake early warning(EEW). After earthquake the system can estimate the magnitude, intensity and epicenter of the earthquake according to the P-wave then provides alerts to the urban area near the epicenter as soon as possible. It is the main idea of the earthquake early warning. This procedure let people take emergency measures early to prevent the more damage from the forthcoming strong ground shaking by the S-wave. The effect of EEW could be evaluated on two aspects, one is how much time EEW spends from the earthquake occurs until it sends the alert, the other one is the accuracy of the estimated earthquake information in the alert. The proposed method in this paper focuses on the accuracy of the estimated information. Previous research on detecting and timing the P-wave in real-time usually use the single signal collected by a station. In this paper we propose the Cross-Correlation P-wave Detection(CCPD) scheme to utilize the similarity among the signals from different stations to automatically detect and pick the time for P-wave. We first choose the seed station according to the signal quality of the stations then calculate the score and P-wave arrival times based on cross-correlation coefficients with neighbor stations. Subsequently, we set the thresholds to filter the imprecise P-arrival time. Finally, we make a simulation as EEW works in real time to explain how to set the thresholds to filter the imprecise calculated P-wave arrival times and verify the effect of CCPD method by taking those filtered P-wave arrival times into localizing the epicenter.