新震模信息法與地震群湯模型之研究;A study on an improved pattern informatics method and the soup-of-group model for earthquakes

NCUIR > College of Earth Sciences > Graduate Institute of Geophysics > Electronic Thesis & Dissertation > Item 987654321/77023

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/77023

Title:	新震模信息法與地震群湯模型之研究;A study on an improved pattern informatics method and the soup-of-group model for earthquakes
Authors:	張齡云;Chang, Ling-Yun
Contributors:	地球科學學系
Keywords:	地震活動度;震模信息法;群湯模型;seismicity;pattern informatics method;soup-of-group model
Date:	2018-08-06
Issue Date:	2018-08-31 13:10:34 (UTC+8)
Publisher:	國立中央大學
Abstract:	要直接測量複雜地震斷層系統中的狀態變數是相當困難的，但透過測量型態變數(如：地震活動度)的變化可以了解系統的狀態。震模信息法是計算地震活動度變異量的方法，其物理概念是透過在希爾伯特空間中分解出地震活動度於時間空間的基本型態(特徵向量)，計算地震活動度在變化區間中每個位置之狀態向量的相位角飄移量，因而得到與災害地震相關的地震活動度異常區。Cheong[2014]將群湯模型應用在地震系統的研究，由粒狀介質的交互作用結合和分裂成各種大小的叢集模擬地震系統，並貼切的展現出許多觀察到的地震特性，如冪律分布等。本研究中首次利用群湯模型中災害地震發生前地震活動度在不同的規模段都會產生變化的特性改良震模訊息法。新式震模信息法會先計算不同規模段的相對機率，再相乘所有相對機率得到新的相對機率。利用新式震模信息法本研究規律計算了每個月的熱點圖，並觀察規模大於5.5之目標地震的前兆現象，再以ROC法檢測計算結果，最後發現利用新方法所得到之異常區比原始方法更加顯著且和災害地震有密切的關係，有效的改善了低地震活動度區雜訊的問題。相較於之前僅計算一個時間點的PI值，本研究透過除以時空中最高的PI值，可以同時比較及考量空間中所有網格在所有時間點的PI值，得到可能隱含地震發生機率概念的「絕對PI值」，也可以訂出對於全部時間和空間而言與災害地震有關聯性的絕對PI高值區域。 ;Earthquakes originate from a driven nonlinear threshold system. It’s impossible to fully understand the dynamical processes and measure the internal state variables, but we can know the system by pattern state. Rundle et al. purposed the Pattern Informatics (PI) method to analyze the changes of seismicity before and around a large earthquake[Rundle et al., 2003; Tiampo et al., 2002a; Chen et al., 2005; 2006; Wu et al., 2008a]. In this study, we calculated the anomaly area which associated with large earthquakes in Taiwan region by PI method from Taiwan CWB earthquakes catalog. Chenong et al. [2014] well applied the Soup-of–group (SOG) model, a mathematics model, to earthquakes system. In SOG earthquake model, the numbers of small events had expectation decreased (seismic quiescence) in order of magnitude before the large earthquake occur. Therefore, in this study, we first time ever improved the PI method, inspired from SOG model, by calculating the change of seismicity rate by dividing the magnitude range into several segments and multiple them to get a new PI relative probability. We retrospectively tested the target earthquakes with magnitude larger than 5.5 from 2000 to 2016 by new PI method, and objectively evaluated the performances of the new method by the Relative Operating Characteristic (ROC) method which were significantly better than original results. Finally, we obtained absolute PI values by comparing the PI values of all the grids in space at 204 timing, and it was possible to define a true absolute high value region for all of time and space in the future calculations. The most important is that the future large earthquakes will occur with high probability in these anomaly areas determined by absolute PI high value from this study, so there is a high probability that absolute PI values can be delicate converted into the probability of earthquake occurrence.
Appears in Collections:	[Graduate Institute of Geophysics] Electronic Thesis & Dissertation

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