Taal Volcano
Quick Reference Notes

Location: Batangas Province, 60km South of Manila (14° 00 1’N – 120° 59.6° E)

Physical Characteristics:
Type of Volcano:  A complex of cinder and tuff cones formed inside a large caldera
Main Rock Type: Olivine Basalt
Area of Volcano Island: 23 sq. km
Highest Point of the Volcano Island: 311 m asl – SW rim of the Main Crater
Base Diameter:  5 km
Volume: 2 km³
Area of Taal Lake: 267 sq km; 2m asl( lake level); depth 100m (N portion) 150-160m (S portion)
Cones and Craters: 35 identified cones (26tuff cones, 5 cinder cones, 4  maars) and 47 craters
Main Crater: 1.9 km in dia; blue-green in color; 4m asl; deepest point: 76m; pH 2.3-2.5, site of 12 historical eruptions from 1749 to 1911 (1749, 1754, 1790, 1808, 1825, 1842, 1873, 1874, 1878, 1903, 1904 and 1911)
Taal Caldera: 25km across; formed between 140,000 to 5,380 B.P.
Major Adjacent Volcanic Edifices: Mt. Makiling, My. Batulao, Mt. Sungay, Mt. Malepunyo, Mt. Macolod

Historical Eruptions:
No of Redcorded Eruptions: 33 since 1572
Last Eruption: 03 September 1977 (phreatic eruption)
Destructive Eruptions:
1749 - destroyed the entire Volcano Island and the towns of Taal, old Sala and part of old Tanauan
1754 - destroyed towns of Sala, Lipa, tanauan and Talisay
1911 - devastated Volcano Island killed 1334 people; ashes reached Manila
1965 – affected the entire Volcanic Island;  ashfall covered an area of 60sq km; killed 200 people

Historical Eruption Centers:
Main Crater (e.g 1749, 1754, 1911 eruptions)
Binintiang Malaki (e.g. 1767, 1715 eruptions)
Binintiang Munti (e.g. 1709, 1731 eruptions)
Pira-piraso (1731 eruption)
Off Calauit (1716 eruption)
Mt. Tabaro Eruption Site (1965-1970, 1976-1977 eruptions)

Eruption Types:
Phreatic-steam-driven explosion (e.g. 1878, 1911, 1970)
Phreatomagnetic – steam-driven with magma involved (e.g. 1749, 1965, 1966)
Strombolian –quiet lava emissions (e.g 1968, 1969)
Plinian- eruption of great violence characterized by voluminous explosive ejections of pumice and ash flows (1754 eruption)

Known Precursors to Historical Eruptions
-Increase in frequency of quakes with occasional felt events accompanied by rumbling sounds
-Increase temperature and level of Main Crater Lake
-Development of new thermal areas/ reactivation of old ones
- Ground swells or inflation and ground fissuring

Philippine Institute of Volcanology and Seismology
Volcano Monitoring and Eruption Prediction Division
-Increase in temperature of ground probe holes at Mt. Tabaro
-Sulfuric odor and acrid fumes
-Fish kills and drying up of vegetation

Phenomena Associated with Eruption
-Base surges – rapidly moving mixtures of volcanic debris and steam
-Ash falls and ballistic projectiles
-Lava flows
-Seiches/ Tsunamis and flooding
-Fissuring and ground subsidence
-Lakeshore Landslide

Monitoring Techniques:
Monitoring Method:

1. Geophysical Methods:
• Seismic Monitoring – telemetered seismic network; seismographs at Buco and Pirapiraso
2. Geodetic Methods- ground deformation
• Electronic Distance Measurement (EDM)
• Precise leveling
• Tilt measurement (wet and dry)
3. Multi-parameter  digital telemetry – seismic, tilt, temperature, acoustics, radon, conductivity, water level
4. Geochemical and geothermal methods (pH, silica, chloride, Mg/CL ratio)
5. Visual Observations

Monitoring Stations:
-Buco Observatory – 9.7 km N of Main Crater (120°59.06’E, 14°05.10’N)
-Tagaytay Observatory -11.3km NW of Main Crater (120°56.04’E, 14°06.18’N)

Evacuation Scheme/ High Danger Zones
Areas to be evacuated in case of eruption similar (in nature and magnitude) to:
1965 activity – entire Volcano Island and 4 lakeshore barangays of Agoncillo and laurel
1911 activity – entire Volcano Island; and lakeshore barangays of Talisay, Tanauan, Agoncillo, Balete, San Nicolas and Laurel