臺灣博碩士論文加值系統

震災向來是台灣的主要天災之一，降低震災帶來的生命財產損失也一直是人們努力的目標，然而人類目前在科學技術上未能準確預測地震會何時發生，因此產生地震預警(Earthquake Early Warning, EEW)的概念與研究：當地震發生時，盡快偵測到並估算地震資訊，將預警警報發送至全國各地，讓人們能做好地震即將來襲的應對準備，間接降低震災造成的財物損失與人員傷亡。
本文建立了一個地震預警系統，使用測站數量超過400個、佈置於台灣各地的Palert地震網，相當於一個高密度的地震感測網路，收集測站的感測資料並使用STA/LTA觸發器用來偵測地震初達波P波的到達，當偵測到地震事件後並對震源位置進行定位。有別於地面上的一般定位，地震震源定位是一個三維空間的定位問題，而且地震波在地殼內的傳遞速度並非等速而會隨著地形、地質、深度等因素而不同，本文利用不同測站有著不同的P波到達時間此一特性，使用理論到時差與觀測到時差設計一個等時差吻合度模型，並以經度、緯度、深度三個不同維度將地形切割成一個三維虛擬網格，虛擬網格中的最小單位稱為細胞，任意一個細胞皆可套入等時差吻合度模型並得到一個吻合度數值，此數值相對越高代表越吻合目前的已知條件。換句話說吻合度最高的細胞即是震源位置，對於如何找到吻合度最高的細胞，提出相鄰搜尋法的演算法。在實驗中，搜集2013年全年發生在台灣本島與沿海，芮氏規模超過4.0以上的地震感測記錄，並以窮舉搜尋法、尺度收縮搜尋法及Geiger定位法做為比較對象，從結果來看，相鄰搜尋法有著計算速度快、定位準確及定位結果穩定的優點，證明可實際運用於地震預警及地震防災上。

Earthquakes have always been a major disaster in Taiwan, but due to our inability to accurately predict the occurrence of an earthquake, the concept and study of EEW (Earthquake Early Warning) emerged: when an earthquake occurs, if we can detect it and estimate its properties as soon as possible, we can send out warnings and let people prepare for the incoming disaster, indirectly reduces the damage of properties and losses of lives from an earthquake.
This study created a novel EEW system utilizing the Palert network, a high density sensor network consisting of over 400 detection sites deployed across Taiwan. When we detect the first arrival wave with the STA/LTA triggers, we can determine whether an earthquake have occurred and locate the hypocenter. Unlike traditional locating problems, the position of the hypocenter is 3-dimensional. Thus, we created a scoring model that takes advantage of the different P-wave arrival time between detection sites, then divide the terrain into a 3-dimensional virtual grid based on longitude, latitude and depth. The virtual grid is composed of various cells, with each cell having a score under the scoring model. The higher the score, the more the cell fits into the known parameters of the hypocenter. In other words, the highest-scoring cell is the hypocenter, and we purpose a neighborhood method for finding this cell. In our experiments, we gathered every earthquakes occurred on 2013 in Taiwan or the surrounding sea with a magnitude greater than ML4.0, and we compare our method to an exhaustive method, a downscaling method and Geiger's method. From the results, our neighborhood method has the advantages of high speed, accurate location and stable results, proving that our method can be readily applied to EEW and disaster prevention.

第一章 緒論 1
1.1 背景 1
1.2 研究動機與目標 2
1.3 研究方法 3
1.4 本文貢獻 4
1.5 論文架構 5
第二章 相關文獻探討 6
2.1 地震預警的回顧與發展 6
2.2 P波偵測與估算相關研究 7
第三章 系統架構 10
3.1 系統簡介 10
3.2 感測訊號 11
3.3 資料接收與轉發 12
3.4 資料處理與計算 13
第四章 偵測與定位方法 15
4.1地震偵測方法 15
4.2 一維連續速度模型與走時 18
4.3 虛擬網格與等時差吻合度模型 21
4.4 相鄰搜尋法 23
第五章 模擬結果與效能評估 25
5.1 比較方法 25
5.1.1 窮舉搜尋法 25
5.1.2 尺度收縮搜尋法 25
5.1.3 Geiger定位法 27
5.2 實驗環境及參數 28
5.3 測站數對偵測率的影響 29
5.4 測站數對定位結果的影響 30
5.5 震央與深度定位結果平面圖 34
5.6 案例討論 44
5.6.1 03月27日南投縣仁愛鄉芮氏規模6.2地震 44
5.6.2 06月02日南投縣魚池鄉芮氏規模6.5地震 46
5.6.3 10月31日花蓮縣萬榮鄉芮氏規模6.4地震 48
第六章 結論與未來展望 51
參考文獻 53

[1]Y.-M. Wu, and H. Kanamori, “Experiment on an onsite early warning method for the Taiwan early warning system,” Bulletin of the Seismological Society of America, vol. 95, no. 1, pp. 347-353, Feb. 2005.
[2]Y. Nakamura, “UrEDAS, urgent earthquake detection and alarm system, now and future,” Proceedings of the 13th world conference on earthquake engineering, 2004.
[3]S. Horiuchi, H. Negishi, K. Abe, A. Kamimura, and Y. Fujinawa, “An automatic processing system for broadcasting earthquake alarms,” Bulletin of the Seismological Society of America, vol. 95, no. 2, pp. 708-718, Apr. 2005.
[4]T. Odaka, K. Ashiya, S. Y. Tsukada, S. Sato, K. Ohtake, and D. Nozaka, “A new method of quickly estimating epicentral distance and magnitude from a single seismic record,” Bulletin of the Seismological Society of America, vol. 93, no. 1, pp. 526–532, Feb. 2003.
[5]Y.-M. Wu, and H. Kanamori, “Exploring the feasibility of on-site earthquake early warning using close-in records of the 2007 Noto Hanto earthquake,” Earth Planets and Space, vol. 60, no. 2, pp. 155, 2008.
[6]Y.-M. Wu, H. Kanamori, R. Allen, and E. Hauksson, “Determination of earthquake early warning parameters, τc and Pd, for southern California,” Geophysical Journal International, vol. 170, no. 2, pp. 711-717, 2007.
[7]Y.-M. Wu, H.-Y. Yen, L. Zhao, B.-S. Huang, and W.-T. Liang, “Magnitude determination using initial P waves: A single‐station approach,” Geophysical Research Letters, vol. 33, no. 5, 2006.
[8]C.E. Johnson, A. Bittenbinder, B. Bogaert, L. Dietz, and W. Kohler, “Earthworm: A flexible approach to seismic network processing,” Iris newsletter, vol. 14, no. 2, pp. 1-4, 1995.
[9]Y.-M. Wu, D.-Y. Chen, T.-L. Lin, C.-Y. Hsieh, T.-L. Chin, W.-Y. Chang, W.-S. Li, and S.-H. Ker, “A High‐Density Seismic Network for Earthquake Early Warning in Taiwan Based on Low Cost Sensors,” Seismological Research Letters, vol. 84, no. 6, pp. 1048-1054, Nov. 2013.
[10]Y.-M. Wu, and T.-L. Lin, “A test of earthquake early warning system using low cost accelerometer in Hualien, Taiwan,” Early Warning for Geological Disasters, pp. 253-261, 2014.
[11]Y. Fujinawa, Y. Rokugo, Y. Noda, Y. Mizui, M. Kobatashi, and E. Mizutani, “Efforts of earthquake disaster mitigation using earthquake early warning in Japan,” The 14th world conference on earthquake engineering, 2008.
[12]J.M. Aranda, A. Jimenez, G. Ibarrola, F. Alcantar, A. Aguilat, M. Inostroza, and S. Maldonado, “Mexico City seismic alert system,” Seismological Research Letters, vol. 66, no. 6, pp. 42-53, 1995.
[13]N.-C. Hsiao, Y.-M. Wu, T.-C. Shin, L. Zhao, and T.-L. Teng, “Development of earthquake early warning system in Taiwan,” Geophysical research letters, vol. 36, no. 5, 2009.
[14]K.-S. Liu, T.-C. Shin, and Y.-B. Tsai, “A free-field strong motion network in Taiwan: TSMIP,” TAO, vol. 10, no. 2, pp. 377-396, Jun.1999.
[15]Y.-M. Wu, T.-C. Shin, C.-C. Chen, Y.-B. Tsai, W. H. K. Lee, and T.-L. Teng, “Taiwan rapid earthquake information release system,” Seismological Research Letters, vol. 68, no. 6, pp. 931-943, Nov. 1997.
[16]Y.-M. Wu, W. H. K. Lee, C.-C. Chen, T.-C. Shin, T.-L. Teng, and Y.-B. Tsai, “Performance of the Taiwan rapid earthquake information release system (RTD) during the 1999 Chi-Chi (Taiwan) earthquake,” Seismological Research Letters, vol. 71, no. 3, pp. 338-343, May 1997.
[17]W.H.K. Lee, T.-C. Shin, and T.-L. Teng, “Design and implementation of earthquake early warning systems in Taiwan,” Proc. 11th World Conference on Earthquake Engineering, 1996.
[18]Y.-M. Wu, T.-C. Shin, and Y.B. Tsai, “Quick and reliable determination of magnitude for seismic early warning,” Bulletin of the Seismological Society of America, vol. 88, no. 5, pp. 1254-1259, Oct. 1998.
[19]Y.-M. Wu, J.-K. Chung, T.-C. Shin, N.-C. Hsiao, Y.-B. Tsai, W. H. K. Lee, and T.-L. Teng, “Development of an integrated earthquake early warning system in Taiwan-Case for the Hualien area earthquakes,” TAO, vol. 10, no. 4, pp. 719-736, Dec.1999.
[20]R. Allen, “Automatic earthquake recognition and timing from single traces,” Bulletin of the Seismological Society of America, vol. 68, no. 5, pp. 1521-1532, Oct. 1978.
[21]R. Allen, “Automatic phase pickers: their present use and future prospects,” Bulletin of the Seismological Society of America, vol. 72, no. 6b, pp. s225-s242, Dec. 1982.
[22]R. Allen, and H. Kanamori, “The potential for earthquake early warning in southern California,” Science, vol. 300, no. 5620, pp. 786-789, Sep. 2003.
[23]Y. Nakamura, “On the urgent earthquake detection and alarm system (UrEDAS),” Proc. of the 9th World Conference on Earthquake Engineering, vol. 7, pp. 673-678, Aug. 1988.
[24]H. Kanamori, “Real-time seismology and earthquake damage mitigation,” Annu. Rev. Earth Planet. Sci., vol. 33, pp. 195-214, Dec. 2004.
[25]Y.-M. Wu, and H. Kanamori, “Development of an earthquake early warning system using real-time strong motion signals,” Sensors, vol. 8, no. 1, pp. 1-9, 2008.
[26]L. Geiger, “Probability method for the determination of earthquake epicenters from the arrival time only,” Bulletin of St. Louis University, vol. 8, no. 1, pp. 56-71, 1912.
[27]S. Satriano, A. Lomax, and A. Zollo, “Real-time evolutionary earthquake location for seismic early warning,” Bulletin of the Seismological Society of America, vol. 98, no. 3, pp. 1482-1494, Jun. 2008.
[28]F. Aurenhammer, “Voronoi diagrams—a survey of a fundamental geometric data structure,” ACM Computing Surveys, vol. 23, no. 3, pp. 345-405, Sep. 1991.
[29]K.R. Anderson, “Epicentral location using arrival time order,” Bulletin of the Seismological Society of America, vol. 71, no. 2, pp. 541-545, Apr. 1981.
[30]D.P. Schaff, and D. Waldhauser, “Waveform cross-correlation-based differential travel-time measurements at the Northern California Seismic Network,” Bulletin of the Seismological Society of America, vol. 95, no. 6, pp. 2446-2461, Dec. 2005.
[31]P.M. Shearer, “Improving local earthquake locations using the L1 norm and waveform cross correlation: Application to the Whittier Narrows, California, aftershock sequence,” Journal of Geophysical Research: Solid Earth, vol. 102, no. b4, pp. 8269-8283, Apr. 1997.
[32]T. Sakaki, M. Okazaki, and Y. Matsuo, “Earthquake shakes Twitter users: real-time event detection by social sensors,” Proceedings of the 19th international conference on World wide web, pp. 851-860, Apr. 2010.
[33]T. Sakaki, M. Okazaki, and Y. Matsuo, “Tweet analysis for real-time event detection and earthquake reporting system development,” IEEE Transactions on Knowledge and Data Engineering, vol. 25, no. 4, pp. 919-931, Apr. 2013.
[34]I.V. Rodriguez, “Automatic Time-picking of Micro seismic Data Combining STA/LTA and the Stationary Discrete Wavelet Transform,” CSPG CSEG CWLS Convention, convention abstracts, 2011.
[35]S.W. Stewart, “Principles and applications of micro earthquake networks,” Academic Press , vol. 2, 1981.