1Seismic Studies in the Mount Peulik/Becharof

• Main Authors: Seth Moran, Peter Haeussler, John Power
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Anchorage; alaska range; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.582.4554; http://www.scec.org/instanet/01news/es_abstracts/moranEarthscope_2001_abs.pdf

The Mount Peulik/Becharof Lake area (MPBL) is located on the Alaska Peninsula approximately 530 km southwest of Anchorage (Figure 1). This region includes a number of important transitions in magmatic-tectonic trends: 1) A major subduction zone segment boundary defined by the western extent of the 1964 Great Alaskan Earthquake (Mw 9.2) and the eastern extent of the 1938 Mw 8.2 earthquake; 2) A dramatic change in volcano spacing and alignment between the tightly-spaced Katmai volcano group to the east and Chiginagak, Aniakchak, and Veniaminof volcanoes to the west (Figure 2) (this change is also associated with the southern terminus of contiguous mountains that make up the Alaska Range); 3) A hypothesized zone of crustal weakness, defined by the volcanic vents of Mount Peulik and the Ukinrek Maars (Figure 2), several lineaments along the southwestern shoreline of Becharof Lake, and anomalous shallow seismic swarms occurring in 1977 and 1998 near Becharof Lake (Figure 2). Each seismic swarm occurred in associ-ation with nearby magma movement; the 1977 swarm in association with the eruption of Ukinrek Maars (Estes, 1978; Kienle et al., 1980), the 1998 swarm in association with magma intrusion beneath Mount Peu-lik, detected via InSAR, that may have triggered the swarm (Lu et al., in press). Figure 1. Map showing the location of the Mount Peulik/Becharof Lake area. Also plotted are locations of major faults (brown lines), rupture zones for the Mw9.2 and Mw8.2 earthquakes, Holocene volcanic centers (yellow stars), and historically active volcanoes (pink stars).