An Eastern Aleutian Trench Seismic Record
R. von Huene, J. Miller, M. Fisher, G. Smith, 1983. "An Eastern Aleutian Trench Seismic Record", Seismic Expression of Structural Styles: A Picture and Work Atlas. Volume 1–The Layered Earth, Volume 2–Tectonics Of Extensional Provinces, & Volume 3–Tectonics Of Compressional Provinces, A. W. Bally
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After the 1964 Alaska earthquake, seismic records were collected across the eastern Aleutian Trench to study subduction-zone tectonics because geologic and seismologic studies indicated a subduction-related cause. Single-channel seismic-reflection records collected during the 1960s penetrated strata in the trench and about 1,000 m (3,281 ft) of rocks under the slope; only rarely was the top of the igneous oceanic crust detected for more than several kilometers beneath the front of the subduction zone (von Huene, 1972). In the first published multichannel seismicreflection records across the eastern Aleutian Trench (Seely, 1977), the reflection from the oceanic crust can be traced about 40 km (25 mi) landward of the trench, and the deformed stratification above this crust was shown in sufficient detail that a general structural style could be outlined. Structural style was also apparent in a series of records collected subsequently (von Huene, 1979; von Huene et al, 1979), but none of these multichannel records are migrated. The record presented here, from the Aleutian subduction zone off southern Kodiak Island (Figure 1), is migrated. A comparison of the unmigrated and migrated sections shows the improved resolution of structural detail that results from the migration process. This record and those from previous publications show a remarkable diversity of structural style in the subduction zone near Kodiak Island. In the record displayed here, the foot of the landward slope of the trench has a relatively simple structure in comparison with that evident in adjacent records from a seismic network off southern Kodiak Island. This record exemplifies one structural style of the subduction zone off southern Kodiak Island and shows the local formation of thrust packets within an accretionary complex.