At about 2 PM on January 12, 2020, the second most active volcano in the Philippines (Taal Volcano) started to spew ashes prompting the Philippine Institute of Volcanology and Seismology (Phivolcs) to raise its alert status to Level 2 due to the volcano's phreatic eruption.
Around 4 pm, Phivolcs again raised the alert to Level 3 following "magmatic unrest" and 1-km ash column.
Three hours later, the ash column reached up to 10-15 km above ground prompting the agency to raise the alert to Level 4 indicating that a hazardous eruption is imminent.
Three provinces from CALABARZON Region (Batangas, Cavite, Laguna) were heavily affected. Residents from the nearby towns were advised to evacuate especially those that are leaving in the main Taal volcano island and the permanent danger zones. By Sunday night, the ash fall has reached Manila (about 70km from the volcano) while most of the nearby towns also experienced ash falls with larger rock particles.
Since the incident, a lot of volunteers from various sectors have extended their assistance to the people affected by the eruption. While the volcano appears to be in a calm situation, the alert Level 4 has not been lifted and most of the neighboring towns are still in partial lockdown for returning residents.
In this exercise, I intended to explore some spatial questions that might be helpful in understanding the current situation in the point of view of the responders, emergency management units, and local government officials of the affected areas.
Specifically, this exercise aims to answer some of the basic questions like:
In addition, I also looked at the impact of the eruption on the schools and students within the three provinces that were heavily affected.
The first task is to identify the areas that are within the 14-km permanent danger zone designated by Phivolcs. Basic overlay techniques like Multi-ring Buffer was used to create different buffer zones indicating the danger zones. The administrative boundary layer was added on the map as well to query those that are within the 14, 17, and 20-km danger zones.
The overlay analysis showed that 208 barangays are within the 14-km permanent danger zone, while 390 barangays are within the 17-km danger zone. Also, looking at the 20-km extended danger zone, 583 barangays are located within it.
To get an estimate of the number of the affected population, I used the 2010 Census data available on the municipal level from the Philippine Statistics Agency. Among the 87 cities and municipalities of the three provinces, 29 are within the 20-km extended danger zone. An estimated 2,510,367 residents are living within the 20-km danger zone.
Since the eruption, Google also started to crowdsource data of the Evacuation Centers. As of January 15, 224 Evacuation centers were mapped. However, it is also interesting to note that some ECs are still located within the danger zones.
In the Philippines, schools are often used as evacuation centers. This means that during emergency scenarios, classes were also heavily disrupted. As of Jan 31, classes in the primary and secondary levels are still canceled affecting 782 schools within the three provinces. Using the enrolment data in 2017, an estimated 878,970 students are affected.
With his, I also derived some of the schools that can be used as potential evacuation centers. These are schools that are within 30 km from the volcano and do not fall within the danger zones.
You can also click this link to the Story Map I created for an interactive version of the web map.
Note: This will be available as long as the contents are accessible from the ZGIS ArcGIS Online organization account.
