HR: 1330h
AN: S12A-0377 [PDF]
TI: Earthquake Induced Water Waves in Washington State
AU: * Barberopoulou, A
EM: aggeliki@ess.washington.edu
AF: University of Washington, Department of Earth and Space Sciences, Seattle, WA 98195 United States
AU: Qamar, A
EM: tony@ess.washington.edu
AF: University of Washington, Department of Earth and Space Sciences, Seattle, WA 98195 United States
AU: Pratt, T L
EM: tpratt@ocean.washington.edu
AF: University of Washington, US Geological Survey, School of Oceanography, Seattle, WA 98195 United States
AB:
The Mw 7.9 Denali earthquake of 3 November 2002 caused minor damage to at least 20 houseboats by initiating water waves in
Lake Union, Seattle, Washington. Damage caused by unusual water activity is not uncommon in Washington State. Newspaper
reports show that damage also has been caused by water waves in the Seattle area during local or distant earthquakes in 1899
(Yakutat Bay Alaska earthquake), 1949 (Olympia earthquake) and 1965 (Seattle-Tacoma earthquake). Analysis of Pacific
Northwest Seismic Network (PNSN) recordings of the Denali earthquake demonstrates that large water waves are due in part to
local amplification of seismic waves by the underlying Seattle sedimentary basin. Simple formulae predict water wave
amplitudes only half or smaller than those reported for swimming pools and lakes. Resonance initiated by multiple cycles of
surface waves, focusing, and near-shore effects could further amplify the water waves. To understand the type and origins of
these water waves, we are examining the response of a water body of rectangular shape and rectangular cross-section subjected
to hypothetical forcing functions, and to forcing functions derived from seismograph records of major earthquakes. The
results provide estimates of the potential wave heights during future large earthquakes on the nearby subduction zone or on
local faults.
DE: 1845 Limnology
DE: 4560 Surface waves and tides (1255)
DE: 7200 SEISMOLOGY
DE: 7223 Seismic hazard assessment and prediction
SC: Seismology [S]
MN: 2003 Fall Meeting