MAYON VOLCANO

Alert Level	Monitoring Network
Hazard Map	Volcano Observatory
Chronology of Historical Eruption

NAME OF VOLCANO:                        MAYON

LOCATION:                                         Albay, 300 km southeast of Manila

                                                             (13°15.4'N, 123°41.1’E)

PHYSICAL FEATURES

Elevation:  2.46 km          

Base Diameter:  20 km

Base Circumference:  62.8 km (reckoned from 10-km radius) encompassing the towns of Camalig, Malilipot and Sto. Domingo                   

Area:  314.1 km² (estimated from 62.8 km base circumference)

Type of Volcano:  Stratovolcano                         

Adjacent Volcanic Edifice:  Mt. Malinao, Lignon Hill and Balong Gloria Hill

GEOLOGICAL FEATURES

Rock Type:  Basalt to Olivine-bearing Pyroxene Andesite         

Tectonic Setting:  Bicol Volcanic Chain

VOLCANIC ACTIVITY

Number of Historical Eruptions:  48

Latest Eruption/Activity:

14 July 2006 (mild eruption – quiet effusion of lava) - on going

Eruption Type:

1. Strombolian  (e.g.. 1978, 1st phase of 1984 eruption)

2. Vulcanian  (e.g. 1st phase of 1968 eruption, 2nd phase of 1984 eruption)

3. Plinian  (e.g. 1814)

 Precursors to Eruptions:

1. Increase in seismicity level  (Background: 0-10 volcanic quakes per day)

2. Ground tilt due to magma intrusion.

3. Change in color of steam emission from white to gray due  to entrained ash

4.  Increase in the volume of steam emission

5.  Crater glow due to  presence of magma at or near the  crater.

6. Rumbling sounds due to gas explosions, wall fracturing, landslides

VOLCANIC HAZARDS

Type of Hazards:

1. Airfall tephra

2. Lava flows

3. Pyroclastic flows

4. Lahars

Permanent Danger Zone:  six (6) km radius from the summit

MONITORING ACTIVITY

Volcano Observatory:  Lignon Hill Observatory (LHO) - 12 km SSE of the summit   (123°43.56’ E, 13°09.64’N)

Monitoring Methods:

1. Seismic monitoring (number of volcanic quakes and tremors)

2. Ground deformation (precise leveling, electronic tilt, GPS)

3. Visual observations

4. Sulfur dioxide emission rate (by COSPEC)

5. Water well monitoring

Monitoring Stations

A - Seismic Network

·         Digital Permanent: Lignon Hill Observatory,  Upper Anoling,  Upper Sta. Misericordia and Mayon

                        Rest House with repeater sites at Mt. Bariw, Upper Sto. Domingo and Tabaco

·         Digital Mobile: Upper Mayon Rest House, Upper Masarawag and Lignon Hill Observatory with

                        repeater sites at Ligao and Camalig

·         Analog: Upper Anoling

B - Ground Deformation

·         Precise leveling lines:  Buang Junction to Mayon Rest House (20 benchmarks); Lidong (13

                          benchmarks) and Anoling

·         GPS stations: Legazpi (Lignon Hill), Sto. Domingo (San Andres), Malilipot (Calbayog),

                         Tabaco  (MRH), Malinao, Ligao (Nabonton) and Camalig (Upper Anoling, Tinago, and

                          Palanog)

·         Permanent Electronic tilt: Upper Anoling, Buang  and Mayon Rest House

·         Mobile electronic tilt: Upper Anoling, Lower Anoling and Upper MRHO