An Updated Lagrangian Finite Element Approach for Tsunami Modeling in Compressible Fluids

Session: Fifty Years of Tsunami Science: from the 1964 Earthquake and Tsunami to the SAFRR Tsunami Scenario – Advances in Tsunami Source Characterization, Numerical Analysis and Hazard Mitigation

 

 

In this work, we have developed an updated Lagrangian finite element method to simulate the gravitational waves in compressible fluids. The equation of motion and boundary conditions are evalulated in the deformed configuration. Gravity is explicitly considered. This approach has a simple physical basis and does not require many assumptions in the simulation. It has a potential of increased numerical stability due to the lack of convective terms appearing in the momentum equations in the Eulerian schemes. Additionally, the treatment of boundary conditions is straightforward. This approach allows us to simulate non-linear wave propagation from all gravitational wave sources, without refering to complicated algorithms for adaptive mesh refinements. Our next step is use the same approach to incorporate coseismic landslides in the dynamic rupture models of shallow subduction earthquakes. In Ma and Hirakawa (2013), we proposed that coseismic submarine landslides can occur because large seafloor uplift due to extensive wedge failure significantly steepens the upper wedge slope. For a wedge on the verge of failure initially any steepening of slope can easily lead to landslides, which is an alternative explanation for the large horizontal seafloor displacement observed in the 2011 Tohoku earthquake. By fully coupling dynamic rupture, coseismic landslides, and tsunami propagation in a single code, potentially important interaction of time-dependent seafloor displacements and tsunami excitation and propagation can be rigorously addressed.

Friday, May 2nd / Poster #38 / Cook/Arteaga