The slip behaviour of subduction faults and the viscoelastic rheology of Earth’s mantle govern crustal deformation throughout the subduction earthquake cycle. This Ph.D. dissertation presents research results on two topics: (1) coseismic and postseismic slip of the shallowest segment of subduction faults and (2) postseismic deformation following great subduction earthquakes controlled by mantle viscoelasticity. Topic 1: Slip behaviour of the shallowest subduction faults. By modelling high-resolution cross-trench bathymetry surveys before and after the 2011 Mw 9.0 Tohoku-oki earthquake, we determine the magnitude and distribution of coseismic slip over the most near-trench 40 km of the Japan Trench megathrust. The inferred > 60 m average slip and a gentle increase by 5 m towards the trench over this distance indicate moderate degree of net coseismic weakening of the shallow fault. Using near-trench seafloor and sub-seafloor fluid pressure variations as strain indicators in conjunction with land-based geodetic measurements, we determine coseismic-slip and afterslip distributions of the 2012 Mw 7.6 Costa Rica earthquake. Here, trench-breaching slip similar to the Tohoku-oki rupture did not occur during the earthquake, but afterslip extended to the trench axis and reached ~0.7 m over 1.3 years after the earthquake, exhibiting a velocity-strengthening behaviour. These two contrasting examples bracket a possibly wide range of slip behaviour of the shallow megathrust. They help us understand why large tsunamis are generated by some but not all subduction earthquakes. Topic 2: Postseismic deformation following great subduction earthquakes. Due to the asymmetry of megathrust rupture, with the upper plate undergoing greater coseismic tension than the incoming plate, viscoelastic stress relaxation causes the trench and land areas to move in opposite, opposing directions immediately after the earthquake. Seafloor geodetic measurements following the 2011 Tohoku-oki earthquake, modelled in this work, provided the first direct observational evidence for this effect. Systematic modelling studies in this work suggest that such viscoelastic opposing motion should be common to all Mw ≥ 8 subduction earthquakes. As the effect of viscoelastic relaxation decays with time and the effect of fault relocking becomes increasingly dominant, the dividing boundary of the opposing motion continues to migrate away from the rupture area. Comparative studies of ten 8 ≤ Mw ≤ 9.5 subduction earthquakes in this dissertation quantifies the primary role of earthquake size in controlling the “speed” of the evolution of this deformation. Larger earthquakes are followed by longer-lived opposing motion that affects a broader region of the upper plate. / Graduate

銀行法第125條之2中「違背職務」要件之解釋在實務上分歧甚大，當涉及授信行為時，涉及複雜商業實務與認定，則更顯難解。因此，於第二章中，本文自財務金融領域的觀點，提出授信的定義、種類與目的，分析授信之相關風險與風險因子之判讀方式，並詳介授信實務之流程、職責分配及規範類型，期能描繪出銀行授信行為於真實世界中的輪廓。在第三章中，本文自法律領域的觀點，分析銀行法背信罪之立法背景、與普通背信罪的關聯、各構成要件的解釋。並針對其中「違背職務」要件的解釋爭議，篩選出若干具有代表性的判決用以後續之分析。在第四章中，本文結合了財務金融領域及法律領域的觀點，提出了本文見解。首先，本文援引了德國學者Hefendehl的集體法益與累積犯理論，認為本罪的保護法益為「人民對銀行制度的信賴」，而銀行財產則僅為「個別累積效果的」明文化規定，亦即保護法益的中介載體。接著本文復援引容許風險之概念，主張應實質判斷個案之授信行為是否已逾越容許風險，藉以判斷是否構成違背職務。最後，本文提出了四階層的具體化判準，並指出在實質判斷風險之存否與高低時，應以巴塞爾協定提出的內部評等法，借 EL=PD×LGD×EAD 之公式協助吾人判斷，至於各該風險因子之判讀，亦應參考本文第二章所提及的若干財務金融知識，以做出最合於現實法益變動的判斷。