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NAME OF VOLCANO:                   BULUSAN
LOCATION:                                     Sorsogon Province, 70 km southeast of Mayon Volcano and                                                                                                                                      approximately 250km SE of Manila (12°46.2'N, 124°03'E) 

Elevation: 1.559 km
Base Diameter: 15 km
Type of Volcano: Stratovolcano formed inside a caldera
Hotsprings: San Benon Springs, Mapaso Springs, San Vicente Springs, Masacrot Springs
Craters and Fissure:

1. Crater No. 1 or Blackbird Lake - 20 m in diameter and 15 m deep
2. Crater No. 2 - roughly oval in shape, 60 m by 30 m and 15 m deep
3. Crater No. 3 - approximately 90 m in diameter and 20 m deep
4. Crater No. 4 - near the NE rim, opened during the 1981 eruption
Fissure - located below Crater No. 4, measuring 5 to 8 m wide and about 100 m long

Adjacent Volcanic Edifice: Mt. Homahan, Mt. Binitacan, Mt. Batuan, Mt. Calungalan, Mt. Calaunan, Mt. Tabon-Tabon, Mt. Juban and Mt. Jormajan


Rock Type: Two-pyroxene andesite in Bulusan, dacite associated with caldera
Tectonic Setting: Bicol Volcanic Chain
Date of eruptive deposits:

a) 1500 - 5800 years based on material from pyroclastic deposits
b) 30K+ for caldera deposits


Number of Historical Eruptions: 18
Latest Eruption/Activity: 2017 March 02 01:57 PM - 02:23 PM
Eruption Type:

1. Phreatic (e.g. 1918-1922, 1980)
2. Strombolian (e.g. 1918-1919)
3. Caldera-forming (e.g. 40,000 YBP)

Precursors to Eruption:

1. Increase in the frequency of volcanic quakes with rumbling sounds
2. Increased steaming activity
3. Noticeable increase in the extent of drying up of vegetation around the volcano's upper slopes
4. Variation in the temperature of hot springs at San Benon
5. Rumbling sound
6. Increased amount of whitish to yellowish deposits of sulfur sublimates at NNW portion of the crater


Type of Hazards:

1. Pyroclastic flows (hot blasts, hot avalanche)
2. Lava flows
3. Lahars
4. Ashfall

Permanent Danger Zone: Four (4) km radius from the summit
Other Buffer Zones: 4 to 10 km from the summit (Probable Danger Zone)


Volcano Observatory: Bulusan Volcano Observatory, Cabid-an, Sorsogon City
Monitored Methods:

1. Seismic
2. Ground deformation – precise leveling, electronic distance measurement (EDM), tilt
3. Hotspring temperature and flow rate measurements
5. Visual observations – steaming activity and other visually observed phenomena

Monitoring Stations:

A - Seismic Network
· Bulusan Volcano Observatory, Sorsogon City (VBN)
· Upper Inlagadian Hill Seismic Station (VBIH)
· Upper Mayong Payong Hill Seismic Station (VBMH)
· Mt. Jormajan Repeater Site (VBRJJ)
· Upper San Roque Seismic Station (VBSR)
· Salvacion Slope Repeater Site (VBSS)

B - Ground Deformation Network
· EDM : Survey lines at Salvacion-Hinde and Aniog-Lower Slope
· PRECISE LEVELING: Survey line at Mapaso
· TILT MEASUREMENT (wet) - San Benon