## 1 Introduction  
Seismic events in a subduction zone are strongly related to its thermal structure. The eastern Aleutian Islands, Alaska Peninsula (southwestern Alaska) and south-central Alaska represent seismically devastating subduction zones constituting an active plate margin with geological and structural complexities under high earthquake risk and are linked to various tectonic processes [1]. The composition of the downgoing oceanic crust beneath Alaska is heterogeneous and varies along strike with distinct topographic features (Figure 1). The contrasting slab morphologies between southwestern and south-central Alaska depend on the effects of variable dynamic, kinematic and geometric factors (e.g., [2]). Southwestern Alaska features active volcanism and abundant seismicity, which extends westward to the Aleutian Islands above a steeply subducting oceanic crust [3; 4; 5]. [PERSON] et al. [6] have found that the seismic events and arc magmatism occurring here show a trend of along-strike variation. South-central Alaska exhibits a corner geometry in map view (e.g., [7; 8]), where the oceanic plate is bounded to the east by the Queen Charlotte-Fairweather transform system [9]. The Yakutat block, a subducted oceanic plateau rafted to its current location by the motion of the Pacific plate for at least 23 Myr [10], is subducted 600 km inland of the trench [9] with a thick oceanic crust [11]. In the mantle wedge, the back-arc low-velocity zone extends to depths of 100-150 km, implying that the downward-moving oceanic plate releases fluid/melts into the mantle wedge through dehydration processes, and the mafic magma is then transferred into the wedge [3; 5; 12]. Furthermore, the distribution of volcanoes and the associated arc magmatism in south-central Alaska are thought to be controlled by overlying and subducting plates [13]. Figure 1: Tectonic map. The color indicates surface topography (ETOPO, [14]). The light blue dotted line marks the model area. The yellow arrows denote the direction (orientation) and velocity (length) of subduction, and the red barbed lines mark convergent plate boundaries (with the teeth on the overriding plate). The red curves represent the isodepth contours of the subducted Pacific plate with a contour interval of 20 km (Slab 2.0, [15]). Red triangles indicate arc volcanoes [16]. The colored spheres all indicate M > 3 earthquakes (IRIS) from 1 January 2000 to December 2010 and all M > 5.5 earthquakes from 1 January 1900 to December 2000 (Centennial Database). Earthquake magnitudes are indicated by sphere color. The blue ellipses with dashed lines represent the slow slip event patches in the Upper Cook (2008\(-\)2012, [17]) and Lower Cook Inlets (2010\(-\)2011, [18]). Green areas show the distribution of deep tremors [19]. The green dashed line indicates low-frequency earthquakes [20]. Bold blue bold lines indicate the 1992.0-2004.8 (\(\sim\)M 7.8) Slow Slip Event, and bold red lines indicate the 2009.85-2011.81 (\(\sim\)M 7.2) Slow Slip Event [21; 22]. The white dashed lines indicate the Kaltag Fault and Western-Central Denali Fault [23]. Numerous large earthquakes have historically occurred in Alaska, such as the Mw9.2 Great Alaskan earthquake of 1964, the Mw8.6 Aleutian Islands earthquake of 1946, and the Mw 8.2 Alaska Peninsula earthquakes of 1938 and 2021 (Figure 1). After four minutes and thirty-eight seconds, The Great Alaskan Earthquake (Mw9.2) is recognized as the second-most powerful earthquake in recorded world history, during which 970 km of the fault ruptured and moved up to 18 m, and an 8.2 m tsunami destroyed the village of Chenega and caused damage as far away as Hawaii and Japan (Tsunami Research Group, 2015). In regard to recent GPS observations, slow slip events (SSEs, [24]) in south-central Alaska are segmented due to along-strike variations in plate coupling, such as the SSE patches in the Upper Cook [17; 25; 26] and Lower Cook Inlets [18]. Deep tremors are estimated to occur in south-central Alaska (e.g., [19; 27]) (Figure 1).