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Recurring non-eruptive unrest at Taal (Philippines). R.U. Solidum, E.P. Laguerta and Taal Monitoring Team Philippine Institute of Volcanology and Seismology (PHIVOLCS). Volcano Observatory Best Practices Workshop: Near-term Eruption Forecasting 11-15 September 2011.
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Recurring non-eruptive unrest at Taal (Philippines) R.U. Solidum, E.P. Laguerta and Taal Monitoring Team Philippine Institute of Volcanology and Seismology (PHIVOLCS) Volcano Observatory Best Practices Workshop: Near-term Eruption Forecasting 11-15 September 2011
Introduction to PHIVOLCS – major activities • Monitoring, warning and advisory services on volcanic and earthquake hazards, including tsunami • - national seismic network • - 6 volcano observatories • Hazard mapping and risk assessment services • Research and development • Disaster preparedness and risk mitigation services
Introduction to PHIVOLCS – links (some) • Member of the Technical Working Group of the Disaster Risk Reduction and Management Councils (DRRMC) at National level and Regional to Provincial Level if present in area • Office of Civil Defense (OCD) • Local governments • Key government agencies – land use and development planning; local governance; education • Non-government organizations • Media
Tectonic Setting of the Philippines • ~300 volcanoes: • 23 active • 26 potentially active
Taal Caldera South China Sea Metro Manila Tagaytay City Main Crater Lake Taal Caldera Taal Lake Volcano Island
Historical Eruptions at Volcano Island • 33 eruptions since 1572 • latest eruption: October 1977 Historical Eruption Sites • Main Crater (1572, 1591, 1605-1611, 1634, 1635, 1641, 1645, 1749, 1754, 1790, 1808, 1825, 1842, 1873, 1874, 1878, 1903, 1904, 1911) • Binintiang Malaki (1707, 1715) • Binintiang Munti (1709, 1729) • Pira-piraso (1731) • Off Calauit (1716) • Mt. Tabaro (1965, 1966, 1967, 1968, 1969, 1970, 1976, 1977)
Some Destructive eruptions of Taal 1754 (15 May-30 Nov) – Main Crater; Plinian; VEI 4; ?dead 1911 (27 Jan- 7 Feb) – Main Crater; Phreatic; VEI 3; 1335 dead 1965 (28 to 30 Sep) – Mt. Tabaro; Phreato-magmatic; VEI 4; ~200 dead Taal base surge, 1965
Areas affected by 1754 base surge Tagaytay City Old Tanauan Mt. Batulao Old Lipa Eruption site Balayan Agoncillo Calaca Mt. Makulot Old Taal Data Sources: Arboleda and Ruelo, (1986); Torres, (1989) Lemery 0 20 Taal kilometers Areas affected by base surges (1754)
1911 1965 Eruption site Eruption site km km 0 4 0 4 Areas affected by base surges Areas affected by base surges (1911, 1965) Data Sources: Pratt (1911); Worcester (1912); Moore, Nakamura and Alcaraz, (1966); Moore (1967); Arboleda and Ruelo, (198x)
Base Surge Hazard Map At risk: ~5000 people on Volcano Island at least 100,000 people around Taal Lake
Taal Volcano Seismicity (1990-1999) Pira-piraso Station
Description of some unrest in Taal • 1991 Mar to Jul - increased seismicity up to 45 VT events/day; some felt at Intensities I-V; intense bubbling at Main Crater Lake (MCL); geysering at MCL; lake T increased by 2C • 1992 Feb 14-28 - dramatic increase in seismicity with 2550 VT events within 24hrs, several were felt; decreased to baseline within 2 weeks; Volcano Island uplifted up to 20cm; fissuring at northeastern slopes; intense bubbling at MCL; lake T increased by 2C (Alert level 2 then 3 – evacuation of Volcano Island) • 1994 Mar 11-31 - escalating increase in seismicity with 1550 VT events within 24hrs, several were felt at Intensities I-II; inflation of Volcano Island up to 16cm; fissuring at eastern slopes; intense bubbling at MCL; lake T increased by 5C (Alert level 3 – evacuation of Volcano Island)
SUMMARY OF SEISMIC SWARMS/UNRESTS AT TAAL VOLCANO Description of some unrest in Taal • 2010 Apr - June - increase in VT events, several were felt; slight inflation of Volcano Island; bubbling at MCL; lake T increased by 2-3C; increased steaming at Crater Lake (Alert level 2 - Main Crater off limits) • 2011 Apr-May – increase in VT events, several felt at Intensities I-III; quakes from 4km to 1km beneath Volcano island; preceded by CO2 flux of 4600 t/d in late March, 4 times background measurement (Alert level 2 – Main Crater off limits)
CO2 Flux (2008-2011) CO2 flux from ITER (Spain)-PHIVOLS collaboration Graph from Arpa et al, 2011
Communication of Forecast (via fax, email, web, phone) NDRRMC Head OP VAAC Tokyo Darwin PHIVOLCS HQ OCD National NDRRMC Members OCD Region DRRMC PHIVOLCS Observatory CAAP National Local Met Office National Local Province DRRMC Media National Media Local City/Town DRRMC CAAP – Civil Aviation Authority of the Philippines NDRRMC- National Disaster Risk Reduction and Management Council OCD – Office of Civil Defense OP- Office of the President Village DRRMC Public
Awareness and Preparedness Activities (Town of Laurel – 2008)
Awareness and Preparedness Activities (Village of Bilibinwang, Agoncillo – 2008) Village Captain Civil Defense Director
Some on-going initiatives for Taal • Improvement of monitoring systems: • - seismic telemetry (currently 8 stations: 4SP, 4BB) • - deformation (currently 3cGPS, one e-tilt; precise leveling, EDM) • - electromagnetism • - gas geochemistry (CO2) • - Main Crater Lake observations (chemistry, T) • * With international partners from NIED and Japanese institutions (JICA-JST), EMSEV Group, ITER (Spain), others? • Awareness and preparedness at local level with province and OCD Region • Advocacy for appropriate land use and development • planning
THANK YOU! www.phivolcs.dost.gov.ph PHIVOLCS Building, CP Garcia Ave. UP Campus, Diliman, Quezon City Tel 426-1468; Fax 9298366