Recurring non-eruptive unrest at Taal (Philippines)

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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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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

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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

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Tectonic Setting of the Philippines

• 300 volcanoes
• 23 active
• 26 potentially active

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Taal Caldera
South China Sea
Metro Manila
Tagaytay City
Main Crater Lake
Taal Caldera
Taal Lake
Volcano Island
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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)

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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
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Areas affected by base surges (1754)
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Areas affected by base surges (1911, 1965)
Data Sources Pratt (1911) Worcester (1912)
Moore, Nakamura and Alcaraz, (1966) Moore
(1967) Arboleda and Ruelo, (198x)
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Base Surge Hazard Map
At risk 5000 people on Volcano Island at
least 100,000 people around Taal Lake
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(No Transcript)
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Response Action Based on Alert Level
ALERT LEVELS RESPONSE
Alert Level 1 Main Crater is off limits to the public because sudden explosions may occur or toxic gases may accumulate. Volcano Island residents and visitors must be aware and vigilant of the volcanos condition.
Alert Level 2 Main Crater, Daang Kastila and 1965-1977 Mt. Tabaro Eruption Site are off limits to the public. Selective evacuation women, children and elderly at the Volcano Island are advised to transfer to their relatives at the mainland.
Alert Level 3 Total evacuation of the Volcano Island.
Alert Level 4 Flank eruption lakeshore barangays facing eruption sitel Eruption site Main Crater lakeshore barangays of Talisay, Tanauan, Agoncillo, Balete, San Nicolas and Laurel. Additional areas to be evacuated shall be determined based on the development of escalating activity and possible location of eruption site.
Alert Level 5 Expansion of risk areas depending on the magnitude of eruption.
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Taal Volcano Seismicity (1990-1999) Pira-piraso
Station
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Taal Volcano Seismicity (2000-2011)
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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)

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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)

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Taal Volcano Seismicity (2005, 2008, 2010, 2011)
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Precise Leveling at SE slope
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CO2 Flux (2008-2011)
CO2 flux from ITER (Spain)-PHIVOLS
collaboration Graph from Arpa et al, 2011
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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
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Awareness and Preparedness Activities (Town of
Laurel 2008)
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Awareness and Preparedness Activities (Village of
Bilibinwang, Agoncillo 2008)
Village Captain
Civil Defense Director
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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

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THANK YOU!
www.phivolcs.dost.gov.ph PHIVOLCS Building, CP
Garcia Ave. UP Campus, Diliman, Quezon City Tel
426-1468 Fax [phone]