Awareness and Preparedness
|Taal Volcano Advisory|
|Tuesday, 08 June 2010 10:41|
Taal Volcano Bulletin
08 June 2010
This is a notice for raising the alert level status of Taal Volcano from Alert Level 1 to Alert Level 2.
Beginning last week of April 2010, monitored parameters have shown anomalous change as indicated by the following observations:
1. Since 26 April 2010, the number of volcanic earthquakes detected per day continued to increase. For the past 24 hours, 32 high frequency volcanic earthquakes were detected. The size of recorded earthquakes has also been increasing. In addition, a low frequency type volcanic earthquake was detected on 02 June 2010.
2. Temperature measurement of the Main Crater Lake had increased to 34.00C on 24 May 2010, higher by 2.0 – 3.00C from the previous measurement last 11 May 2010 of 32.00C. The composition of Main Crater Lake water has shown above normal values of Mg/Cl, SO4/Cl and Total Dissolved Solids.
3. Continuous ground temperatures and total magnetic field measurements installed by PHIVOLCS-EMSEV at Daang Kastila and in the Main Crater showed increasing trends.
4. Steaming activities at the northern and northeast sides of the Main Crater occasionally intensified. Sometimes, intensification of steaming activity is accompanied by audible hissing sounds.
5. Precise leveling measurements showed that the volcano remains slightly inflated since 2004. Initial result of precise leveling survey conducted yesterday at the southeast side of the Volcano Island showed further inflation by 3.0 mm.
The recorded high frequency volcanic earthquakes could be the result of active rock fracturing associated with magma intrusion beneath the volcano. The fractures served as passageways through which hot gases from the intruding magma could escape into the Main Crater Lake.
In view of the above observations and the interpretation that a fresh batch of magma has been intruding towards the surface, as manifested in the seismic swarms in 1992, 1994, 2000 and 2004 to present, Taal Volcano’s status is now raised to Alert Level 2, meaning that the volcano is undergoing magmatic intrusion which could eventually lead to an eruption. PHIVOLCS reminds the general public that the Main Crater remains off-limits because hazardous steam-driven explosions may occur, along with the possible build-up of toxic gases. Areas with hot grounds and steam emission such as portions of the Daang Kastila Trail are considered hazardous. PHIVOLCSreiterates that the whole Volcano Island is a Permanent Danger Zone (PDZ) and permanent settlement within this area is strictly prohibited.