Science of Tsunami Hazards Volume 19, pages 150-170 (2001)
MODELING THE LA PALMA LANDSLIDE TSUNAMI
Charles L. Mader
Mader Consulting Co.
Honolulu, Hawaii USA
The tsunami expected from a lateral collapse of the Cumbre Vieja Volcano on La Palma
in the Canary Islands was modeled. The flank collapse for a ‘worst case” landslide was
modeled as a 650 meter high, 20 kilometer radius water wave after 30 kilometers of travel
as predicted by physical modeling studies of Fritz at ETH in Zurich, Switzerland.
The modeling was performed using the SWAN code which solves the nonlinear long
waver equations. The tsunami generation and propagation was modeled using a 10 minute
Mercator grid of 600 by 640 cells. The small wavelength and period of the tsunami expected
from the landslide source results in an intermediate wave rather than a shallow water
tsunami wave. The use of a shallow water model only describes the geometric spreasing
of the wave and not the significant dispersion such a short period wave would exhibit.
Dispersion would reduce the wave amplitudes to less than one-third of the shallow water
The upper limit shallow water modeling indicates that the east coast of the U.S.A. and
the Caribbean would receive tsunami waves less than 3 meters high. The European and
African coasts would have waves less than 10 meters high.
Full Navier-Stokes modeling including dispersion and geometric spreading for the Fritz
initial wave profile predicts that the maximim wave amplitude off the U.S. east coast would
be about a meter. Even with shoaling the wave would not present a significant hazard.
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