The Earthquake Engineering Online Archive

Geotechnical engineering reconnaissance of the November 3, 2002 Mw 7.9 Denali earthquake, Alaska [electronic resource]

Kayen, Robert E.; Sitar, Nicholas; Carver, Gary A.; Collins, Brian; Moss, Robb E. S.

UCB/EERC-2003/04, Earthquake Engineering Research Center, University of California, Berkeley, 2003, Website (400/E177/2003-04)

Following the Denali, Alaska, earthquake, the authors conducted a reconnaissance of the region to investigate the geotechnical engineering features of the event. The focus of the investigation was to characterize the spatial extent and amplitude of ground failures and to assess damage to structures. The most noteworthy aerial observations were that geotechnical and structural damage appeared to be focused towards the eastern end of the Denali-Totschunda fault rupture area. Sparse sand vents and lateral spreads on bars of the western Tanana River, from Fairbanks to Delta, became pervasive to the east. Likewise, for the four glacier-proximal rivers draining toward the north, little or no liquefaction was observed on the western Delta and Johnson Rivers; whereas, the eastern Robertson and Tok Rivers and, especially, the Nabesna River had observable-to-abundant fissures and sand vents. Ice on frozen lakes and ponds was shattered within about 30-40 km of the fault along the western part of the surface rupture and to the east became more widespread. In the Northway region, ice on most lakes was broken at distances of more than 100 km. Where the fault crossed the trans-Alaska pipeline, strong shaking, inertial motions, and permanent offset of the fault beneath the pipe resulted in damage to 8 horizontal support members and 9 anchored supports near the fault crossing. The pipe is free to slide on Teflon skids; and, in numerous locations, especially south of the fault, the pipe collided with vertical support members. These effects were not critical to the integrity of the pipeline, which performed well during the event.

Available online: http://eerc.berkeley.edu/research/denali