Dr. Carla B. Dimalanta is a Professor at the National Institute of Geological Sciences (NIGS) at the University of the Philippines – Diliman specializing in exploration and marine geophysics. She earned her PhD in Earth and Planetary Sciences from the University of Tokyo, Japan. Her research integrates gravity and magnetic data to investigate Philippine ophiolites, delineate mineralization potential in key mineral districts and estimate crustal thickness. She advances arc-continent collision zone studies and provenance analyses of sedimentary sequences to identify continent-derived fragments. Additionally, she has contributed to an understanding of oceanic basins and proto-Philippine Sea Plate fragments through integrated geological and geophysical datasets. Recent initiatives apply edge detectors to global and regional gravity and magnetic datasets for mapping unmapped offshore faults and estimating heat flow in subduction zones.
Seismogenic Potential of the Manila Trench: Insights from Integrated Geophysical Datasets
C.B. Dimalanta1, L.T. Armada1, C.V. Malipol1, J.G. Cuevas1, E.J.M. Maglalang1,2, G.P. Yumul, Jr.1,3 and Shu-Kun Hsu4
1National Institute of Geological Sciences, College of Science, University of the Philippines, Diliman, Quezon City, Philippines
2School of Earth and Environmental Sciences, Cardiff University, Cardiff, Wales, United Kingdom
3Cordillera Exploration Company, Inc., Bonifacio Global City, Taguig City, Philippines
4Department of Earth Sciences, College of Earth Sciences, National Central University, Taiwan
Global and regional datasets, including gravity, magnetic and seismicity, are invaluable for investigating seismogenic potential in datasparse offshore regions like the Manila Trench. Recent investigations into the trench’s seismogenic potential to generate magnitude 8+ earthquakes and associated hazards, have advanced from the use of these datasets amid complexities from ridge subduction, impingement variations between its northern and southern segments, and heterogeneous sediment budgets driven by mass wasting and erosion. Edge detection filters applied to gravity and magnetic anomalies from the World Gravity Model (WGM2012) and World Digital Magnetic Anomaly Model (WDMAM2.2) reveal previously unmapped fault splays, which are possible offshore extensions of the Philippine Fault Zone. Magnetic data further enable heat flow estimation through Curie Point Depth analysis in subduction zones. This is vital for areas where direct measurements of heat flow data are not available. Strain rates from earthquake focal mechanism solutions from the Global Centroid Moment Tensor (GCMT) and geodetic datasets highlight the mechanical behavior of the subducting slab along the trench. Integrating these approaches provides a reassessment of the Manila Trench mega-thrust’s seismogenic potential, refining hazard models and underscoring the need to understand the evolution of this trench system.