Map of tectonic settings around Mayon volcano, Philippines

Map of tectonic settings around Mayon volcano, Philippines

Major tectonic structures around Mayon volcano (southeast Luzon, Philippines): central segment of the Philippine fault and the major fault splays identified south and north of it (after Lagmay et al, 2005).

Tectonically, Mayon is located in the Bicol Basin (Oas Graben), a northwest trending structural depression. Structural analysis of previous study reveals a regional transtensional stress regime in the Bicol basin, which induced the northwest striking leftlateral faults to have a normal slip component (Lagmay et al., 2005). The Oas Graben bounded by Legaspi Lineament to the north and San Vicente Linao Fault to the south. The Legazpi Lineament (N70oW) is seismically active and is a left-lateral fault with a normal component to the east (Le Rouzic, 1999). GPS data analysis (Rangin et al., 1999) derived a left-lateral motion of 13 mm/yr along the Legaspi Fault with 13 mm/yr of extension perpendicular to it.

References: 

A.M.F. Lagmay, A.M.P. Tengonciang, H.S. Uy, Structural setting of the Bicol Basin and kinematic analysis of fractures on Mayon Volcano, Philippines, Journal of Volcanology and Geothermal Research, Volume 144, Issues 1–4, 15 June 2005, Pages 23-36, ISSN 0377-0273, 10.1016/j.jvolgeores.2004.11.015.