This section needs to be updated. (January 2020)
Phreatic explosion captured at the main crater of Taal Volcano. Video taken from the installed IP camera
of PHIVOLCS monitoring Taal Volcano
The volcano erupted on the afternoon of January 12, 2020, 43 years after its previous eruption in 1977. According to PHIVOLCS director Renato Solidum, a phreatic eruption was first recorded at around 1 pm Philippine Standard Time (UTC+8). Loud rumbling sounds were also felt and heard from the volcano island. By 2:30 pm, PHIVOLCS raised the alert status to Alert Level 2 after a stronger explosion was recorded around 2 pm. It was followed by an even stronger explosion by around 3 pm that spew an ash column measuring 100 meters, prompting PHIVOLCS to upgrade the alert status to Alert Level 3 by 4 pm. Furthermore, Solidum confirmed that there was a magmatic intrusion that is likely the cause of the volcano's phreatic eruptions on Sunday morning and afternoon. PHIVOLCS ordered an evacuation in the towns of Balete, San Nicolas, and Talisay in Batangas and other towns within the shores of Taal Lake. By 7:30 pm, PHIVOLCS upgraded the alert status to Alert Level 4 after volcanic activities intensified as "continuous eruption generated a tall 10 to 15 kilometres (6.2 to 9.3 mi) steam-laden tephra column with frequent volcanic lightning that rained wet ashfall on the general north as far as Quezon City and Caloocan." Ashfall from the volcano were also experienced in Cavite and Laguna, and reached as far as Metro Manila and Pampanga.
Explosion seen from the Tagaytay City viewdeck
On Monday, January 13, PHIVOLCS reported that the volcano emitted a strombolian type of eruption between 2:48 am to 4:28 am. A lava fountain was recorded at 3:20 am. The Department of Environment and Natural Resources presented a study that the air quality index of cities in Metro Manila had worsened; Mandaluyong had the highest amount of inhalable coarse particulate matter (PM10) with 118, followed by Las Piñas (108) and Taguig (104), all of which were "considered unhealthy for sensitive groups" with respiratory issues. Meanwhile, the cities with the least amount of PM10 were San Juan and Malabon, both with "good" amounts of 22 and 28 respectively. These were followed by "moderate/fair" amounts of PM10 in Pasig (55), Parañaque (62) and Makati (63).
By January 16, European satellites observed that the sulfuric acid which filled the main crater prior to the eruption had almost completely disappeared.
As of Saturday, January 25, the National Disaster Risk Reduction and Management Council (NDRRMC) and the Philippine Institute of Volcanology and Seismology (PHIVOLCS) have reported a total of 950 volcano tectonic earthquakes in the Taal area since the eruption, 176 of which were felt. The strongest were a series of Mw 4.1 magnitude earthquakes originating 6 kilometres (3.7 mi) northwest of Agoncillo, Batangas, which were recorded at least thrice: at 11:56 pm on January 12, 3:11 am on January 13, and 6:35 am later that day. As a result, an Intensity III ("weak") on the PHIVOLCS Earthquake Intensity Scale was felt in Tagaytay and an Intensity II ("slightly felt") was felt in Malabon. Between 11:39 pm on January 13 and 5:50 am the following day, PHIVOLCS reported a total of 44 earthquakes in the towns of Calaca, Laurel, Lemery, Mataasnakahoy, San Luis, Taal and Talisay in Batangas, and Alfonso in Cavite; among the strongest were a magnitude Mw 3.6 in Taal, which was felt at an Intensity III in Tagaytay, and a magnitude Mw 3.9 originating 7 kilometres (4.3 mi) northeast of Talisay at 2:05 am, measuring an Intensity IV ("moderately strong") in Tagaytay and Intensity II in Malabon and Pasay.
As a result of these constant earthquakes, numerous fissures or cracks began to appear across different barangays in the Batangas towns of Agoncillo, Lemery, San Nicolas, and Talisay, the towns within the 14-kilometer radius danger zone of Taal. A fissure also transected the road connecting Agoncillo to Laurel. On Wednesday, January 15, PHIVOLCS reported that the water in the main crater lake on Taal Volcano Island has drained; the lake measured 1.9 kilometers wide and 4 metres (13 ft) above sea level. Portions of the Pansipit River, had also drained as a result of "the ground deformation caused by an upward movement of the magma"; it is the same process that caused the series of earthquakes. PHIVOLCS have also hinted on underwater fissures in Taal Lake where the water may have drained into.