Shallow Crustal Structure Beneath Taal Volcano, Philippines, Revealed by the 1993 Seismic Explosion Survey

Autor: NISHIGAMI, Kin'ya, SHIBUTANI, Takuo, OHKURA, Takahiro, HIRATA, Masaya, HORIKAWA, Haruo, SHIMIZU, Kouichi, MATSUO, Shigemitsu, NAKAO, Setsuro, ANDO, Masataka, BAUTISTA, Bartolome C., BAUTISTA, Ma. Leonila P., BARCELONA, Edito S., VALERIO, Ramses, LANUZA, Angelito G., CHU, Arnold V., VILLEGAS, Jason Jude, RASDAS, Ariel R., MANGAO, Enrico A., GABINETE, Elmer, PUNONGBAYAN, Baby JaneT., NARAG, Ishmael C., MARTE, Felix, PUNONGBAYAN, Raymundo S.
Jazyk: angličtina
Rok vydání: 1994
Zdroj: Bulletin of the Disaster Prevention Research Institute. 44(3):123-138
ISSN: 0454-7675
Popis: We carried out an seismic explosion survey at Taal volcano in March, 1993. The explosions were done at the west of the volcanic island and digital event recorders were deployed along a fan-shooting survey line at the east of the volcanic island and also along a short straight survey line across the island. Small-aperture arrays were also operated at two sites west of the volcanic island. We found that P waves that traveled just beneath the main crater strongly attenuated and showed later arrivals. This result suggests the existence of a low-velocity and low-Q region around the main crater at a depth of about 1.5km, although the location and extent cannot be determined exactly. P wave velocity of this abnormal region may be eatimated to be lower than that of the surroundings by much greater than about 25%, if we assume the region is restricted just beneath the main crater. We applied the NMO correction to the later part of seismograms and found a reflector around the east of the main crater at a depth of about 6km, which may suggest the top surface of the magma reservoir.
Databáze: OpenAIRE