GAK_Q57.TIF - Gulf of Alaska U.S. EEZ GLORIA sidescan-sonar data mosaic (27 of 30) (LCC, 50 m, WGS84)

GLORIA data for the Gulf of Alaska Exclusive Economic Zone (EEZ) were acquired during five cruises over a four year period. The first cruise conducted in 1986 (F-1-86-GA) surveyed an area of the north-central mosaic area and covered an area of approximately 40,000 square kilometers (sq km). The second two cruises (F-8-88-AA, F-9-88-WG) were conducted in 1988. One of the 1988 cruises (F-8-88-AA) focused on a survey of the Aleutian Arc. The eastern most portion of that survey extended outside of the Aleutian Arc survey area and covered an area of approximately 52,000 square kilometers (sq km) of seafloor on the western edge of the Gulf of Alaska. The final two cruises (F-6-89-GA, F-7-89-EG) were completed in 1989. As in earlier EEZ reconnaissance surveys, the USGS utilized the GLORIA (Geological LOng-Range Inclined Asdic) sidescan-sonar system to complete the geologic mapping. The collected GLORIA data were processed and digitally mosaicked to produce continuous imagery of the seafloor. Thirty digital mosaics with a 50-meter pixel resolution were completed for the region.阿拉斯加湾专属经济区（Exclusive Economic Zone，EEZ）的GLORIA数据，系在四年周期内的五次科考航次中采集获取。1986年开展的首次航次（编号F-1-86-GA），勘测范围覆盖北中部镶嵌区，总面积约4万平方千米。1988年共完成两次后续航次（编号分别为F-8-88-AA、F-9-88-WG），其中F-8-88-AA航次以阿留申弧勘测为核心任务。该航次的最东端勘测区域超出了阿留申弧的原定勘测范围，覆盖了阿拉斯加湾西部边缘约5.2万平方千米的海底区域。最后两次航次（编号F-6-89-GA、F-7-89-EG）于1989年完成。与此前的专属经济区踏勘勘测航次一致，美国地质调查局（United States Geological Survey，USGS）采用GLORIA（Geological LOng-Range Inclined Asdic，地质长距离倾斜声呐）侧扫声呐系统完成地质填图工作。采集得到的GLORIA数据经过处理与数字镶嵌，生成了连续的海底影像。本次研究区域共计完成30幅像素分辨率为50米的数字镶嵌影像。