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TAAL VOLCANO UPDATEJune 2010

JAIME S. SINCIOCOOIC, Volcano Monitoring and Eruption Prediction Division

Philippine Institute of Volcanology and Seismology Department of Science and Technology

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TAAL VOLCANO ISLAND: 23 sq km in area; highest point of the island: 311 m asl (SW rim of the Main Crater)

MAIN CRATER: 1.9 km in dia.; blue-green in color; 4 m asl; deepest point: 76 m; site of 12 eruptions from 1749 to 1911

TAAL CALDERA: 25 km across; formed between 140,000 to 5,380 B.P.; major adjacent volcanic edifices: Mt. Sungay, Mt. Batulao, Mt. Macolod, Mt. Malepunyo & Mt. Makiling

No. of recorded eruptions of Taal: 33 since 1572Latest eruption: 03 October 1977

Source: HIGP, Univ. Hawaii

NATURE OF ERUPTION

• Steam-driven eruptions caused by contact of groundwater with hot country rocks (no magma involved)

• Produce short ash columns, ashfall

• Usually precursory to magmatic eruptions

PHREATIC

1976• Weak to violent eruption of gas-

charged fluid magma characterized by lava fountaining and flowing

• Produce lava flows

STROMBOLIAN

1966

1969

PHREATOMAGMATIC• Very violent eruption generated by the explosive

contact of erupting magma with water

• Produce voluminous, slightly tall ash columns, laterally-projected pyroclastic currents (base surges) and blasts

PLINIAN

1991 Pinatubo eruption (Plinian)

• Very explosive, energetic release of voluminous magmatic gas, fragmented magma which propel with great force high in the air, forming huge mushroom clouds

• Very tall eruption column, penetrating stratosphere

• Produce extensive ashfall, pyroclastic flows, large crater

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Eruption centers of Taal Volcano

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Historical Eruption Centers

• 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)

1965 eruption site (Mt. Tabaro)

1911 eruption site (Main Crater)

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• Barangays and sitios of Taal Volcano Island belong to three municipalities. Talisay

Brgy. San Isidro (Tibag) – Sitios Balantoc & Panikihan Brgy. Tabla – Sitios Looc , Bignay, Pira-piraso &Tuoran

San Nicolas Brgy. Alas-as Brgy. Pulang Bato – Sitio Saluyan

Balete Brgy. Calauit

• Taal Volcano Island is a Permanent Danger Zone. It might be affected by various volcanic processes during eruptions that may

originate anywhere in the Island considering that it has 47 eruption centers. Permanent habitation, i.e. continuous occupancy of people, in the Volcano

Island is not allowed, The whole Volcano Island was declared as a National Park during the term

of President Ferdinand E. Marcos under Presidential Proclamation (PP) No. 235.

• On Oct. 6, 1996, President Fidel V. Ramos, through PP No. 906, declared Taal Volcano Island National Park a Protected Area under Category of Protected Landscape

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Current Status• Alert Level 2Alert Level 2• Observed parametersObserved parameters

– Increasing number and size of volcanic earthquakes detected daily; Increasing number and size of volcanic earthquakes detected daily; appearance of low frequency type volcanic quake; sappearance of low frequency type volcanic quake; some of the recorded ome of the recorded volcanic earthquakes were felt at Calauit and Pira-piraso with intensities volcanic earthquakes were felt at Calauit and Pira-piraso with intensities ranging from 1-3 and accompanied by rumbling soundsranging from 1-3 and accompanied by rumbling sounds. .

– Increasing temperature of Main Crater Lake (34°C as of May 24, 2010 Increasing temperature of Main Crater Lake (34°C as of May 24, 2010 compared to 32°C as of May 11, 2010); measurement as of June 8, compared to 32°C as of May 11, 2010); measurement as of June 8, 2010 is 33.5°C); 2010 is 33.5°C);

– Above normal values of Mg/Cl, SO4/Cl and total dissolved solids Above normal values of Mg/Cl, SO4/Cl and total dissolved solids (chemical composition)(chemical composition)

– Increasing trends shown by continuous ground temperatures and total Increasing trends shown by continuous ground temperatures and total magnetic field measurements by PHIVOLCS-EMSEV at Daang Kastila magnetic field measurements by PHIVOLCS-EMSEV at Daang Kastila and Main Crater Lakeand Main Crater Lake

– Occasional intensification of steaming activities at the northern and Occasional intensification of steaming activities at the northern and northeastern side of Main Crater; sometimes accompanied by audible northeastern side of Main Crater; sometimes accompanied by audible hissing soundshissing sounds

– Slight inflation since 2004 as measured by precise leveling; initial result Slight inflation since 2004 as measured by precise leveling; initial result of the survey conducted on June 7, 2010 showed further inflation by 3.0 of the survey conducted on June 7, 2010 showed further inflation by 3.0 mmmm

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Epicentral map as of June 18, 2010

TAAL EPICENTRAL MAPTAAL EPICENTRAL MAPJanuary-June 2010January-June 2010

LEGEND:LEGEND:

Seismic Station

Epicenters

Prepared by: L. Bañes 06/20/10

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Alert Level Criteria Interpretation

0 Background, quiet No eruption in foreseeable future.

1 Low level seismicity, fumarolic, other activity

Magmatic, tectonic or hydrothermal disturbance; no eruption imminent.

2 Low to moderate level of seismicity, persistence of local but unfelt earthquakes. Ground deformation measurements above baseline levels. Increased water and/or ground probe hole temperatures, increased bubbling at Crater Lake.

A) Probable magmatic intrusion; could eventually lead to an eruption. B) If trend shows further decline, volcano may soon go to level 1

3 Relatively high unrest manifested by seismic swarms including increasing occurrence of low frequency earthquakes and/or harmonic tremor (some events felt). Sudden or increasing changes in temperature or bubbling activity or radon gas emission or crater lake pH. Bulging of the edifice and fissuring may accompany seismicity.

A) If trend is one of increasing unrest, eruption is possible within days to weeks. B) If trend is one of decreasing unrest, volcano may soon go to level 2

4 Intense unrest, continuing seismic swarms, including harmonic tremor and/or “low frequency earthquakes” which are usually felt, profuse steaming along existing and perhaps new vents and fissures.

Hazardous explosive eruption is possible within days.

5 Base surges accompanied by eruption columns or lava fountaining or lava flows.

Hazardous eruption in progress. Extreme hazards to communities west of the volcano and ashfalls on downwind sectors.

Taal Volcano Alert Signals

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ALERT LEVELS ACTIVITIES

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 volcano’s condition.

Alert Level 2 Main Crater, Daang Kastila and 1965-1977 Mt. Tabaro Eruption Site are off limits to the public.

Alert Level 3 Selective evacuation – women, children and elderly at the Volcano Island are advised to transfer to their relatives at the mainland.

Alert Level 4 Total evacuation of the Volcano Island.

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.

TAAL HAZARD WARNINGS BASED ON ALERT SIGNALS

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RAISING/LOWERING OF ALERT LEVEL

DATE ALERT LEVEL EVENT

06 April 2000 Alert Level 0

29 September 2004 Advisory issued due to unfounded rumors of an impending eruption

29 October 2004 Alert Level 1 Significant increase in daily seismic count

09 January 2005 Alert Level 1

(reiterated)

Series of volcanic earthquakes recorded; some felt at Intensity II-III at Volcano Island (Pira-piraso)

30 June 2005 Alert Level 0

23 November 2005 Alert Level 1 Slight seismic unrest

08 June 2010 Alert Level 2 Increasing trends in monitoring parameters

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• Base surges (rapid horizontally moving mixture of volcanic debris and steam)

• Lava flow• Seiche (lake water oscillation)

and flooding• Ashfall and ballistic projectiles • Fissuring and subsidence• Volcanic gases• Landslide

Hazards Associated with Eruption of Taal Volcano

1965 base surge

1969 lava flow

Thermal area inside Main Crater

Impacts of Volcanic Hazards

People who perished at the Volcano Island due to base surge

Houses buried by ash during the 1965 eruption

1965 BASE SURGE

TEPHRA FALL

1911 ground fissures Lemery, Batangas

Daang Kastila fissure and landslide

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VOLCANIC UNRESTSYEAR DURATION SEISMICITY GROUND

DEFORMATIONMAIN CRATER LAKE

OBSERVATIONALERT

STATUS

1987 30 Oct. to 04 Nov. Earthquakes felt at the SSW of Taal Lake

No significant change, within noise level.

pH w/in the baseline of 2.5-3No significant change in lake temp

1988 August(two-week period)

Several small amplitude (ave. of 2 mm) high frequency

Slight inflation (water tube tiltmeter)

1989 June to October Ave. of 6 events a day. Epicenters were scattered at MCL to NE of Taal.

Slight inflation at MC and Mt. Tabaro

Small bubbles observed at MCL; no significant change in lake temperature and pH.

1991 March to July Earthquake count up to 45 events a day. Quakes occasionally felt at volcano island (RF I-V). Epicenters at MCL to ENE of Taal.

No significant inflation or deflation was measured

pH values ranged from 2.5 to 2.37; intense bubbling inside the MCL; lake temperature increased from 30 to 32C; geysering at the NNE wall of MCL w/ temp. ranging from 97-100°C; more steaming vents were formed due to fissuring along the thermal area

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VOLCANIC UNRESTSYEAR DURATION SEISMICITY GROUND DEFORMATION MAIN CRATER LAKE

OBSERVATIONALERT

STATUS

1992 14-28 February

Dramatic increase. Total of 2,550 events detected within 24 hours with several felt events but decreased to the baseline in less than two weeks.

Volcano island uplifted up to about 20 cm. Fissuring at Daang Kastila (5-50 mm wide & 20-400 m long; E-W trends and parallel to MC) and at Pira-piraso (2.6 mm wide and 1-2 m long – 5 fissures)

Intense bubbling inside the MCL (detected by acoustic pressure sensor); abrupt increase of 2° in lake temp. as detected by telemetered sensor)

Alert Level 2-3 (total evacuation of TVI )

1994 11 March to 31 May

Escalating increase; total of 1,550 events detected within 24 hours with several felt events (RF I-II); epicenters clustered at the E and SE sides of Taal with depths of <5 km.

Inflation of 16 cm at Daang Kastila and 9.8 cm at Calauit, SE of Taal. Two ground fissures formed at Calauit approx. 70 m apart (8.0 mm and 10 mm wide)

pH values of 2.18 to 2.20; intense bubbling at the E & NE sector of MCL; lake temp. gradually increased from 34C to 39C.

Alert Level 3 (evacuation of women, children and the elderly from TVI)

2000 19 July to 31 October

Seismic swarm; 59 located earthquakes; epicenters covered E and SE of MCL with depths of 2-5 km

No significant change No significant change in Main Crater Lake

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VOLCANIC UNRESTSYEAR DURATION SEISMICITY GROUND

DEFORMATIONMAIN CRATER LAKE

OBSERVATIONALERT

STATUS

2004 23 Sept. to November

Significant increase in daily seismic count; large amplitude earthquakes; epicenters scattered within vicinity of Main Crater, near Binintiang Malaki (NNW) and near Calauit area (SSE); depths of less than 1.0 to 4.0 km beneath the volcano

Slight inflation of the volcanic edifice

No significant change in Main Crater Lake; steaming activity at the thermal areas inside the crater also remained weak

Alert Level 1 (29 October 2004)

2005 Jan. to Feb.; 21 Nov

Series of volcanic earthquakes recorded; some felt at Intensity II-III at Volcano Island (Pira-piraso); epicenters located within Main Crater and SSE near Calauit; depths of less than 1.0 to 4.0 km

No significant change

No significant change Alert Level 1 reiterated in January;

(AL lowered to 0 on 30 June 2005; AL 1 raised on 23 Nov. 2005)

2006 January,

November

January – high level of seismicity; quakes clustered mainly at the East and Southeast sectors of Volcano Island covering the Main Crater and Calauit areas; depths of 2 - 4 km

November 17 - Geysering activity near the shoreline of Main Crater Lake; muddy water spewed 2-3 m high; sulfur stench also observed; MCL temp at 35°C; slight increase in bubbling activity the crater lake

Alert Level 1

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VOLCANIC UNRESTSYEAR DURATION SEISMICITY GROUND

DEFORMATIONMAIN CRATER LAKE

OBSERVATIONALERT

STATUS

2007 June June – Increase in seismic activity; felt at Int. II-III at Pira-piraso; felt also at Calauit; depths of 2.8-3.4 km

June survey – inflation of the volcano edifice

Alert Level 1

2008 August & Sept. Volcanic quakes on 28 Aug. 2008 (12:33 PM and 12:46 PM) were felt at Int. II in Bgy. Pira-piraso with depths of 0.6 to 0.8 km.; epicenters were located at Daang Kastila.Another quake occurred on 30 Sept. 2008 felt at Pira-piraso, Alas-as & Banyaga (Int. I) with epicenters located 650 m west of the Island and depth of 1.7 km.

Deflation – based on Jan, Feb., April & Sept. 2008 measurements

Still inflated – based on 2004 measurements

Investigation conducted on 29 August 2008 showed that there are remarkable changes in the thermal areas at the northeastern and eastern sectors of Main Crater.

Advisory issued to notify concerned authorities and the public of the volcano’s unrest.

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THANK YOU!

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