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South‐central Alaska features a history of massive volcanic activity. How the Denali volcanic gap (DVG) formed and why the Wrangell volcanoes are clustered remain vigorously debated. Investigating the crustal thermal structure can be crucial for understanding subsurface magmatic activity. We present a high‐resolution broadband Lg‐wave attenuation model to constrain crustal thermal anomalies beneath Alaska. Strong Lg attenuation is observed beneath the volcanoes in south‐central Alaska, indicating thermal anomalies and possible melting in the crust. In contrast, the central Yakutat terrane (YT) and DVG are characterized by weak Lg attenuation, suggesting the existence of a cool crust that prevents hot mantle materials from invading the crust. This cool crust is likely the reason for the DVG. Quarter‐toroidal crustal melting with strong attenuation is revealed around the YT. This curved zone of crustal melting, possibly driven by toroidal mantle flow, weakly connects the Wrangell and Buzzard Creek‐Jumbo Dome magmatic chambers. Plain Language Summary: The Alaskan mainland is located at the western end of the North American plate. This region is adjacent to the Bering Sea to the west and overlies the subducting Pacific Plate to the south. The Yakutat microplate subducts northward below Alaska with a velocity similar to that of the Pacific plate but with a lower angle. Many volcanoes have developed in south‐central Alaska, including those in the Aleutian arc, the Buzzard Creek‐Jumbo Dome, and the Wrangell volcanic field (WVF). However, the origins, storage and transport patterns of the magmas feeding these volcanoes are still unclear and under debate. In this study, we conduct Lg‐wave attenuation tomography on the Alaskan mainland and use the results to investigate the regional crustal thermal structure. The imaging results reveal a cold Yakutat terrane and hot crustal features beneath the volcanoes. The Denali volcanic gap is characterized by weak crustal attenuation, indicating that cool crust may have inhibited volcanic activity. Quarter‐toroidal crustal melting is revealed by a curved belt of strong attenuation. The crustal magmatic chambers may weakly connect the WVF and the Buzzard Creek‐Jumbo Dome volcanoes. Key Points: A high‐resolution broadband Lg‐wave attenuation model is obtained for the Alaskan mainlandStrong Lg‐wave attenuation beneath the volcanoes indicates crustal thermal anomalies and meltingA quarter‐toroidal crustal melting belt weakly connects the magmatic chambers beneath the Buzzard Creek‐Jumbo Dome and Wrangell volcanoes [ABSTRACT FROM AUTHOR]

The deformation mechanism in southeastern Tibet since the continental collision between the Indian and Eurasian plates could be explained by several models, including two major classic end-member models, the rigid-block extrusion model and the crustal flow model. Crustal channel flow is likely an important tectonic regime for properly explaining a large number of geological and geophysical observations but remains in competition with the block extrusion model. Consequently, detecting ductile flow connectivity would play a key role in understanding the tectonic evolution of the southeastern Tibetan Plateau. Here, we established a high-resolution broad-band Q Pg model for the crust in SE Tibet by using a joint inversion tomography method based on both single- and two-station Pg data. We verified the stability of the Q Pg tomography by comparing the Q Pg values at 1 Hz between the joint inversion and the two-station method. Two low- Q Pg zones were observed, isolated by the high- Q Pg Emeishan large igneous province (ELIP). Strong Pg attenuation beneath the Songpan-Ganzi Block and Western Sichuan Block may indicate the presence of crustal material flow due to relatively weak rheological strength. Cooled basaltic magma remnants in the inner zone of the ELIP likely block the southeastward migration of crustal materials driven by the gravity and lateral pressure gradient, and restrict the flow to the Western Sichuan Block, resulting in surface uplift and crustal thickening. Strong Pg attenuation near the Xiaojiang Fault and the Red River Fault may result from mantle upwelling in this region. Our Q Pg model, combined with previous results, suggests that the tectonic deformation in the southeastern Tibetan Plateau has been mainly controlled by the effects of crustal channel flow and asthenospheric upwelling since the Late Miocene. [ABSTRACT FROM AUTHOR]

The Anatolian Plateau, currently experiencing rapid uplift and westward escape, records both the termination of oceanic subduction and the conversion to continental collision. The crustal response to the transition of the subduction environment from eastern to western Anatolia can be inferred by the seismic velocity and attenuation structures. With this study, we construct a broadband Lg‐wave attenuation model for the Anatolian Plateau and use it to constrain lateral crust heterogeneities linked to this transition. Crustal Lg attenuation links late Cenozoic magmatism with asthenospheric upwelling by characterizing the lithospheric thermal structure. The widely distributed strong attenuation observed in eastern Anatolia may be related to the crustal partial melting due to mantle upwelling after the delamination and subsequent break‐off of the Bitlis slab. Lithospheric dripping in central Anatolia likely facilitates the mantle flows through the window between the Cyprus and Aegean slabs, which results in the piecemeal low QLg ${Q}_{\mathit{Lg}}$ anomaly in central Anatolia. Plain Language Summary: Different parts of the Anatolian Plateau are in different evolution stages between oceanic subduction and continental collision and currently undergoing plateau uplift and tectonic escape. The regional seismic velocity and attenuation can be used to characterize crustal partial melting and lateral heterogeneity, which can further identify the underlying subduction process. In this study, we construct a high‐resolution broadband Lg‐wave attenuation model for the Anatolian Plateau. Strong Lg attenuation in Anatolia correlates well with late Cenozoic magmatism distributions and can be an indicator of high temperature or partial melting in the crust. Combined with previous studies, we suggest that the mantle upwelling induced by the delamination of the Bitlis slab is likely reworking the crust in eastern Anatolia and is the cause of widespread thermal anomalies there. The lithospheric dripping process in central Anatolia may facilitate the mantle flows through the window between the Cyprus and Aegean slabs, and results in a piecemeal low QLg ${Q}_{\mathit{Lg}}$ anomaly pattern in central Anatolia. Key Points: A high‐resolution broadband Lg‐wave attenuation model is constructed for the Anatolian PlateauWidespread strong attenuation in the eastern Anatolian crust is likely related to slab delaminationThe circular‐shaped attenuation anomaly may result from slab tearing and lithospheric dripping beneath central Anatolia [ABSTRACT FROM AUTHOR]