By Alexandria San Juan Despite weaker activity observed on Taal Volcano's surface, volcanic tremors continued to be felt in the area, signifying a movement of magma underneath that could lead to a hazardous explosive eruption. The Philippine Institute of Volcanology and Seismology (Phivolcs) said "steady steam emission and infrequent weak explosions" were observed in the main crater of Taal in the past 24 hours. PHIVOLCS Director Usec. Renato Solidum explains the maintained Alert Level 4 of Taal volcano by stating that a hazardous eruption may still occur “within hours to days.” He also said that magma is still rising within Taal, as indicated by persistent volcanic earthquakes in the vicinity. (ALVIN KASIBAN / MANILA BULLETIN) This activity, Phivolcs added, generated 50- to 600-meter tall white to dirty white ash plumes that dispersed ash southwest of the Main Crater. However, state volcanologists warned that Alert Level 4 remains hoisted, which means hazardous eruption is still possible within hours or days. Phivolcs director Renato Solidum Jr., said intense activity was still happening underneath the volcano as volcanic earthquakes continued to rattle the area, which means that a significant volume of magma could be moving upward. "Nandyan pa rin yung intense activity na may magma na umaakyat at posibleng magdulot ng mapanganib na pagsabog. Naiiba yung nakikita natin sa taas at ang nangyayari sa ilalim," Solidum said. Earthquakes According to Solidum, 32 volcanic earthquakes were plotted by the Philippine Seismic Network near the volcano from Friday morning to Saturday morning, registered at magnitudes 1.5 to 3.3. This brings the total number of volcanic tremors recorded to 666 since afternoon of January 12. At least 174 of these registered at magnitudes 1.2 to 4.1 and were felt at Intensities I to V. The Taal Volcano Network, which can detect low-frequency tremors, has recorded 876 volcanic earthquakes within the Taal Volcano Island, including six tremor events and 20 low-frequency earthquakes. Solidum said that such intense seismic activity likely signifies continuous magmatic intrusion beneath the Taal edifice, which may lead to explosive eruption. "Ang pagbitak ng lupa at paglindol ay related sa pag-akyat ng magma papunta sa mababaw na parte ng Taal Volcano edifice," "Maraming lindol at patuloy pa rin ang pagkakaroon ng lindol at ang iba dito ay nagpapahiwatag na kumikilos ang magma so nandyan pa rin ang activity," Solidum said the agency was continuously monitoring Taal Volcano to check if there is a downward trend in its activity, but the Phivolcs chief noted that threat of a hazardous eruption still remains. "Kailangan nating tingnan mabuti at mag-observe pa tayo kung patigil na ba talaga ang galaw ng magma. Pero wala pa tayong nakikita, through our Taal Volcano Monitoring Network, na humihina ito," "At habang mayroon pang paggalaw ng magma sa ilalim, ibig sabihin hindi pa talaga ito humuhupa," Ashfall, fissures, and drying up of lake Taal Volcano continued to spew ash and steam at least a week after its phreatic or steam-driven eruption which surprised unaware residents and tourists visiting the picturesque lake. The 50,000-foot ash cloud blanketed nearby towns, including parts of Metro Manila, Calabarzon, and reaching as far as Central Luzon, forcing residents in the 14-kilometer danger zone to immediately evacuate to safer places. Days after the eruption, fissures or cracks on the ground were found in several barangays in Batangas particulary in Sambal Ibaba, Sinisian, Mahabang Dahilig, Dayapan, Palanas, Sangalang, Poblacion, and Mataas na Bayan in Lemery; Pansipit and Bilibinwang in Agoncillo; Poblacion 1, Poblacion 2, Poblacion 3, and Poblacion 5 in Talisay; and Poblacion in San Nicolas. A wide fissure was also spotted across the road connecting the municipalities of Agoncillo and Laurel in Batangas. The cracks documented in these areas have been observed to be widening by a few centimeters since Sunday. According to Phivolcs, fissures were produced through the intrusion of magma into the Taal edifice. On Wednesday, the state volcanology agency announced that Taal Volcano's Main Crater Lake has vaporized, while portions of the Pansipit River, which is the sole drainage outlet of Taal Lake, was drying up. Phivolcs officials cited several explanations, but the most evident was the series of volcanic quakes that caused the water in the lake to drain. With the threats of more volcanic hazards, PHIVOLCS strongly reiterated the need for total evacuation of Taal Volcano Island and high-risk areas identified in the hazard maps within the 14-kilometer radius from the main crater and along the Pansipit River Valley where fissuring has been observed.