IASPEI - Picture Gallery

IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS002 Poster presentation 1839
Large Scale Landslide Tsunami Experiments
Dr. Hermann Fritz
Civil and Environmental Engineering Georgia Institute of Technology
Fahad Mohammed, Jeseon Yoo
Tsunamis are commonly associated with submarine earthquakes. However more than 10% of all
tsunamis are generated by landslides or landslide like volcano collapses with subaerial, partially
submerged or submarine origins. Landslides may pose perceptible tsunami hazards to areas commonly
regarded as immune. A large number of historic and prehistoric slope failures have been reported
covering a broad range of landslide volumes and resulting tsunamis. In recorded history landslide
generated tsunamis have attained local wave heights and runup heights of more than 100m and 500m,
respectively, thereby locally exceeding maximum wave and runup heights of tectonic tsunamis by more
than an order of magnitude. The coupling between the landslide motion and the generated tsunami
waves is of critical importance given the characteristic trans-critical landslide versus tsunami velocity
Froude numbers. Landslide generated tsunamis were investigated in the three-dimensional tsunami
basin at OSU based on the generalized Froude similarity. The landslide emplacement characteristics
were controlled by means of a novel pneumatic landslide tsunami generator. Deformable landslides of
subaerial and submarine origin were modeled with granular materials. State-of-the-art measurement
techniques such as particle image velocimetry (PIV), a digital video system comprising multiple above
and underwater video cameras, multiple acoustic transducer arrays, hydrophones, as well as resistance
wave and runup gauges were applied. The wave generation was characterized by an extremely
unsteady three phase flow consisting of the slide granulate, water and air entrained into the flow. PIV
provided instantaneous surface velocity vector fields, which gave insight into the kinematics of the wave
generation process. At high impact velocities flow separation occurred on the slide shoulder resulting in
a hydrodynamic impact crater. The recorded wave profiles were extremely directional, unsteady, nonlinear
and located in the intermediate water depth wave regime.
Keywords: landslide tsunami, osu, piv