The role of the Investigator Fracture Zone on the Sumatra subduction zone process using high-resolution bathymetry, seismic reflection data and geodynamic modelling
Event Type: Seminar
Event Date: 31 August 2018 - 4:00pm to 5:00pm
Venue: ASE 3D Visualisation Laboratory (N2-B1c-16c)
Speaker: Fernando Villanueva
About the speaker:
Fernando is a PhD Candidate in Exploration Geophysics at Institut de Physique du Globe de Paris in collaboration with the Earth Observatory of Singapore. His research focuses on processing and interpretation of high resolution bathymetric and seismic data acquired in the offshore Western Sumatra. He also works with numerical simulations of wave propagation and geodynamic models. His interest is in the state-of-the-art methodologies for imaging and data processing used to describe the evolution and deformation of the oceanic lithosphere. He holds an M. Sc. Degree in Geophysics from Institut de Physique de Globe de Paris, in France, and a B. Sc. Degree in Computational Physics from Tecnológico de Monterrey, in Mexico.
Fernando has participated in two research cruises in the Indian Ocean on board the French R/V Marion Dufresne. He started his experience in geophysics working as a computational physicist in the petroleum exploration company CGG. Previously, he was a visiting student researcher in the Computational Quantum Chemistry group at Rice University, US, and a student researcher in the Computational Intelligence and Robotics department at Tecnológico de Monterrey, Mexico.
About the event:
Great earthquakes occur mainly on subduction plate boundaries, but what causes the along strike earthquake segmentation remain poorly understood. To understand the earthquake segmentation, we acquired high-resolution seismic reflection and multibeam bathymetry data as part of the MEGATERA experiment in 2015. The survey of this work was located where the Investigator Fracture Zone (IFZ), a linear group of long ridges, impinges the trench along the Central Sumatra subduction zone. The subduction of these four group of ridges (IFR1-IFR4) has a considerable impact on the accretionary wedge morphology, including strike-slip and normal faulting along with thrusts, leading to the development of complex channel systems and basins, and hence erosion. The relief of IFZ ridges has uplifted the forearc sediments, creating subsidence in the wake of subducting ridges. Frontal parts of the subducting ridges have created long-lived thrusts whereas the decollement passes through the sedimentary sequences between two neighbouring ridges. I performed a 3-D numerical geodynamic model to study the stress evolution and pattern deformation of the oblique subduction of the ridges. Finally, I analysed and compared the numerical experiment to the interpretation of the seafloor and subsurface observations. The results indicate that the subducting IFZ might create low inter-plate coupling, acting as a segment boundary, and is a good candidate of having stopped southeastward propagation of the 2005 Mw 8.7 Nias-Simeulue earthquake.