Alice-Agnes Gabriel, Assistant Professor of Geophysics at LMU Munich and the lead researcher from the LMU side of the team. “Incorporating the observed natural complexity of earthquake sources invariably involves the use of numerical methods, highly efficient simulation software, and High Performance Computing (HPC) systems,” said Dr. The team published the results of their research in the Extreme Scale Multi-Physics Simulations of the Tsunamigenic 2004 Sumatra Megathrust Earthquake paper that won the Best Paper award at SC17. Researchers from the Ludwig-Maximilians-Universität Munich (LMU) and the Technical University of Munich (TUM) investigated the 2004 Sumatra-Andaman earthquake to help better understand the dynamics of megathrust earthquakes and tsunamis. This is due to the inaccessibility and the complexity of the geological setting, the general uncertainties on how earthquakes operate and the massive amount of data produced by synthetic scenarios. However, understanding megathrust earthquakes and the tsunamis they cause is challenging. Scientists perform extensive research on earthquakes to learn more about them and to help discover a way to predict when earthquakes will occur. The exact sequence of events involved in the earthquake continues to raise many questions.
The Sumatra earthquake ruptured the greatest fault length of any recorded earthquake and triggered a series of tsunamis, killing up to 280,000 people in 14 countries, and even displaced Earth’s North Pole by 2.5 cm. The resulting Mw 9.1–9.3 megathrust earthquake generated a tsunami that was up to 30m high along the northern coast of Sumatra. Failure of 1300–1500 km of the Sumatra subduction zone caused more than eight minutes of violent shaking. The December 2004 Sumatra-Andaman earthquake was one of the most powerful and destructive seismic events in history. Courtesy of Ludwig-Maximilians-Universität Munich. Each layer is characterized by a different wave speed and thus requires a different mesh resolution.
The subsurface consists of horizontally layered continental crust and subducting layers of oceanic crust. The curved megathrust is intersecting bathymetry, as are the 3 adjacent splay faults: one forethrust and two backthrusts. Complex 3D geometry of the Sumatra subduction zone model. Tectonic plates involved in the Sumatra-Andaman earthquake. These seismic waves, trapped by the softer sedimentary rock in the Rift and Embayment and amplified by the softer sediments above, cause the duration of long-period shaking to be about 30–45 seconds in some areas, including Memphis, Little Rock, and Paducah, Kentucky.Figure 1. These higher amplitude waves are the more damaging surface waves. As the seismic waves propagate away from the hypocenter in all directions, we see successive waves of strong ground shaking that begins moving along the Reelfoot rift and tends to be focused northeast toward Paducah, Kentucky, and southwest toward Little Rock, Arkansas. The colors are keyed to the peak intensity of ground velocity at the surface. The solid straight line in the middle of the New Madrid seismic zone is the surface projection of the modeled fault, which ruptures in the simulation. Your browser does not support the video tag.
Further, the relatively unconsolidated material in the Mississippi embayment amplifies the ground shaking and also traps seismic energy to prolong the duration of ground shaking. It demonstrates the profound focusing effect the Reelfoot rift has on ground shaking produced by earthquakes.
and is intended to show the general character of the long-period ground shaking expected for a large earthquake in the New Madrid seismic zone. The simulation is based on a detailed geologic model of the central U.S. region for a magnitude 7.7 strike-slip earthquake on the southern section of the New Madrid seismic zone. This animation shows the simulated ground motion of the Earth’s surface that could occur in the central U.S.