JDR Vol.10 No.1 pp. 91-98
doi: 10.20965/jdr.2015.p0091


Geometry and Structure of the Philippine Fault in Ragay Gulf, Southern Luzon

Hirotake Yasuda*, Teresito Bacolcol**, Arturo Daag**,
Ericson Bariso**, Emmanuelle Mitiam**, Jaime Marjes**,
and Takashi Nakata***

*Department of Geophysics, Kyoto University, Kitashirakawa-oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan

**Philippine Institute of Volcanology and Seismology (PHIVOLCS), C. P. Garcia Avenue, Quezon City 1101, Philippines

***Department of Geography, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8522, Japan

August 19, 2014
December 18, 2014
February 1, 2015
Philippine fault, Ragay Gulf, submarine active fault, acoustic survey
A 15 km southward offshore extension of the Philippine Fault in the Ragay Gulf near the east coast of the Bondoc Peninsula is recognized and described with 150 newly acquired, high-resolution acoustic reflections. The vertically dipping fault strikes roughly NWSE and exhibits pressure ridges and depression structures indicative of strike-slip movement. The southern portions of the fault exhibit particularly sharp breaks on the seafloor that were probably produced by the 1973 Ragay Gulf Earthquake. Offsets of distinct acoustic layers are interpreted to indicate the strikeslip fault has slipped in earthquakes at least four, and likely more than 11 times during Holocene.
Cite this article as:
H. Yasuda, T. Bacolcol, A. Daag, E. Bariso, E. Mitiam, J. Marjes, and T. Nakata, “Geometry and Structure of the Philippine Fault in Ragay Gulf, Southern Luzon,” J. Disaster Res., Vol.10 No.1, pp. 91-98, 2015.
Data files:
  1. [1] C. R. Allen, “Geological criteria for evaluating seismicity,” The Geological Society of America Bulletin, Vol.86, No.8, pp. 1041-1057, 1975.
  2. [2] T. Nakata, M. Okamura, H. Matsuoka, R. U. Solidum Jr., J. Daligdig, and N. Tungol, “Subsurface structure of the Philippine Fault in Ragay Gulf, Southern Luzon,” Japan Geoscience Union Meeting, 2006.
  3. [3] T. Nakata, A. Sangawa, and S. Hirano, “A report on tectonic landforms along the Philippine fault zone in the northern Luzon, Philippines,” The Science Reports of the Tohoku University. 7th series, Geography, Vol.27, No.2, pp. 69-93, 1977.
  4. [4] M. A. Aurelio, E. Barrier, C. Rangin, and C. Muller, “The Philippine Fault in the Late Cenozoic tectonic evolution of the Bondoc-Masbate-N. Leyte area, Central Philippines,” Journal of Southeast Asian Earth Sciences, Vol.6, pp. 221-238, 1981.
  5. [5] T. Nakata, H. Tsutsumi, R. S. Punongbayan, R. E. Rimando, J. A. Daligdig, A. S. Daag, and G. M. Besana, “Surface fault ruptures of the 1990 Luzon earthquake, Philippines,” Special Publication No.25, Research Center for Regional Geography, Hiroshima University, 1996.
  6. [6] H. Tsutsumi and J. S. Perez, “Large-scale active fault map of the Philippine fault based on aerial photograph interpretation,” Active Fault Research, No.39, pp. 29-37, 2013.
  7. [7] T. J. Fitch, ”Plate convergence, transcurrent faults, and internal deformation adjacent to Southeast Asia and the western Pacific,” Journal of Geophysical Research, Vol.77, No.23, pp. 4432-4460, 1972.
  8. [8] S. B. Yu and L. C. Kuo, “GPS observation of crustal deformation in the Taiwan-Luzon,” Geophysical Research Letters, Vol.26, pp. 923-926, 1999.
  9. [9] T. Bacolcol, E. Barrier, T. Duquesnoy, A. Aguilar, R. Jorgio, R. dela Cruz, and M. Lasala, “GPS constraints on Philippine fault slip rate in Masbate Island, central Philippines,” Journal of the Geological Society of the Philippines, Vol.60, pp. 1-7, 2005.
  10. [10] H. Tsutsumi, Y. Fukushima, P. S. Perez, and J. J. Lienkaemper, “Aseismic creeping of the Philippine fault in Leyte Island, Philippines, revealed by field observation and InSAR analysis,” SSS32-P33, Japan Geoscience Union Meeting, 2013.
  11. [11] H. K. Archarya, “Seismic slip on the Philippine fault and its tectonics implications,” The Geological Society of America, Vol.8, No.1, pp. 40-42, 1980.
  12. [12] E. M. Morante and C. R. Allen, ”Displacement of the Philippine fault during the Ragay Gulf earthquake of 17 March 1973,” The Geological Society of America Abstracts with Programs, Vol.7, pp. 744-745, 1974.
  13. [13] R. E.Wilcox, T. P. Harding, and D. R. Seely, “BasicWrench Tectonics,” The American Association of Petroleum Geologists Bulletin, Vol.57, pp. 74-96, 1973.
  14. [14] T. P. Harding, “Seiemic characteristics and identification of negative flower structures, positive flower structures, and positive structural inversion,” The American Association of Petroleum Geologists Bulletin, Vol.69, pp. 582-600, 1985.
  15. [15] J. Acosta, “Occurrence of acoustic masking in sediments in two area of the continentak shelf of Spein: Ria de Muros (NW) and Gulf of Cadiz (SW)2,” Marine Geology, Vol.58, pp. 427-434, 1984.
  16. [16] T. Nakata and H. Goto, “New geometric criteria for active fault segmentation: Fault branching and d1p-slip distribution pattern along strike-slip faults,” Active Fault Research, No.17, pp. 43-53, 1998.
  17. [17] H. Tsutsumi, J. S. Perez, J. U. Marjes, K. L. Papiona, and N. T. Ramos, “Coseismic Displacement and Recurrence Interval of the 1973 Ragay Gulf Earthquake, Southern Luzon, Philippines,” Journal of Disaster Research, Vol.10, No.1 (this issue).
  18. [18] E. Barrier, P. Huchon, and M. Aurelio, “Philippine fault: A key for Philippine kinematics,” The Geological Society of America, Vol.19, No.1, pp. 32-35, 1991.

*This site is desgined based on HTML5 and CSS3 for modern browsers, e.g. Chrome, Firefox, Safari, Edge, Opera.

Last updated on Jul. 23, 2024