Subsurface Crustal Structure of Kanlaon Volcano, Philippines from 3D Tomography
Christian Joseph Clarito , Winchelle Ian Sevilla, Lois Abigail Jumawan, Mari-Andylene Quintia, and Ma. Antonia Bornas
Affiliations: Department of Science and Technology -- Philippine Institute of Volcanology and Seismology
Presentation type: Poster
Presentation time: Friday 16:30 - 18:00, Room Poster Hall
Poster Board Number: 22
Programme No: 1.5.29
Abstract
Kanlaon Volcano on Negros Island in central Philippines is one of the country's most active volcanoes, with an eruptive history documented since 1866. Over 30 eruptions, primarily phreatic in nature, have been recorded. To gain a better understanding of Kanlaon's subsurface crustal system and the factors influencing its activity, this study conducted the first 3D seismic tomography study of the volcano. The 3D P- and S-velocity models were produced using the free Local Earthquake Tomography (LOTOS) software (Koulakov, 2009) for iterative passive source tomography. Utilizing data from 16 seismic stations of the Kanlaon Volcano Network and nearby stations of the Philippine Seismic Network, the dataset covered a wide range of earthquake depths from May 2017 to November 2024. This allowed the generation of high-quality, topography-corrected volcanic earthquake relocations and to image the volcano's subsurface structure at higher resolution. The observation period includes stages of seismic unrest: the detection of deep long-period (DLP) events in 2017 and VT swarms in June 2020 and September 2024. Preliminary results reveal distinct seismic velocity distributions (Vp and Vs) and Vp/Vs ratios, providing valuable imaging of Kanlaon's magmatic plumbing system. Keywords: Kanlaon Volcano, 3D seismic tomography, magmatic plumbing system ** **