強震發生後經常讓建物結構受損且造成人員傷亡或受困，此時有效的即時評估強餘震風險將有助於緊急救災行動的管理。傳統上使用Reasenberg-Jones (RJ)模型描述餘震的時間-規模風險，而空間風險的評估則利用變動半徑或固定半徑點格法結合RJ模型。事實上在強震發生的短期內，資料蒐集較為困難也稀少，採用點格法評估空間風險效率較低。本文利用2008年M_W 7.9的中國汶川地震發生之前且位於龍門山斷層附近的地震資料建立空間風險模型。加入該空間風險模型推廣RJ模型，記作SRJ模型，用以分析汶川地震後餘震的時空規模風險。根據SRJ模型或是根據RJ模型結合點格法計算龍門山斷層附近餘震的相對風險，並製作相對餘震風險圖進行餘震預警。最後本文根據接收者操作特徵曲線及其延伸的統計準則，評估藉由相對餘震風險圖預警未來餘震發生區域的效果。本文發現使用歷史地震資料所建立的空間模型，可改善點格法在即時評估空間風險時面臨資料稀少的問題，且能夠有效預警單一斷層地震的強餘震於未來一段時間內發生的空間。

After a drastic earthquake, the building structures are damaged and some people may be trapped or hurt. At this moment, the near real-time assessment of strong aftershocks is needed for the management of emergency rescue. To do so, the RJ model is conventionally used to describe the time-magnitude hazard of aftershocks. The RJ model incorporating with the gridding method with a fixed radius or varying radii is traditionally used to assess the spatial hazard of aftershocks. However, in the early stage of a drastic earthquake, data collection is difficult. Hence, the sparsely data usually bring up a less efficient assessment of spatial hazard aftershock. Therefore, a new spatial hazard model is constructed based on data before the 2008 M_W7.9 Wenchuan earthquake near the Longmenshan fault. The model is denoted by SRJ model since it is a generalization of the RJ model with the spatial hazard. The relative aftershock hazard (RAH) map can be obtained by using the SRJ or the gridding based methods. Finally, according to a variety of criteria based on receiver operating characteristic curve, the effectiveness of different RAH maps is evaluated on depicting the hazardous area of future large aftershocks of the Wenchuan earthquake.

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