Red flags in Building Houses Near Volcanic Zone

By:Rena Mae Gocotano|January 17, 2020

Lethal and beneficial are just in every two sides of a coin for those people who live close to volcanoes. These cones of lava and ash have a wide range of effects on humans. Surprisingly, people rely on volcanoes for their survival every day. Ironic yet true. The soil is fertile, and a lot of volcanic products can be used in an individual’s day by day hustle. For example, sulfur is used as an ingredient in matches and medicine; fine volcanic deposits such as gravel and sand found in rivers are suitable for building materials; thermal energy can be used to generate electric power. But with the risk and danger volcanoes naturally possess, is it all worth it?

Last January 12, 2020, Taal volcano, located in San Nicolas Batangas, Philippines, spewed a devastating eruption across Luzon. It has been a long breath of fresh air for locals since its last outbreak in 1977, but this year, Taal is prompting to remind people of being one of the country’s most active volcanoes. Authorities have urged a total evacuation of nearly a million people near the capital Manila. The Philippine Institute of Volcanology and Seismology (PHIVOLCS) has raised the alert level to four, which indicates an “explosive eruption” could happen eventually. The highest alert level is five, meaning an eruption is taking place. According to the United Nations Office for the Coordination of Humanitarian Affairs (OCHA), there are two zones of concern around the volcano. Around 459,000 people reside within a danger zone with a 14-kilometer (8.7 miles) radius around a volcano, while more than 930,000 people live in a wider17-kilometer (10.5 miles) danger zone. Residents within the immediate area are most at risk from the effects of a potential eruption, including a possible volcanic tsunami.

The danger awaits just under the ground where no one can predict precisely when. Locals and other people who intend to build houses just around the zone of an active volcano must follow certain meter distance for safety. One should also know the different degrees of risk zones and the standard design structure of the house near a particular volcanic area.

Extreme Risk Zone


This zone is the most active vent of the volcano where the threat of danger is above the high level. No houses and individuals can ever survive the actual extent of this zone. The intensity of the area cannot be accurately measured as it depends on one volcano to another, and for some instances, extremes and high risks zone merge.

High-Risk Zone

The high-risk zone is an area where volcanic projectiles fall regularly. Any chances that a person gets close to this section can nearly be injured or killed. However, if one has a strong reason for entering such risk, one should limit time in this region to the shortest time possible. This zone often extends up to 1km from the volcano outlets where colossal eruptions produce heavy ashfall, especially if one is near valleys where pyroclastic flows are channeled.

Medium Risk Zone

Though this zone is considered comparatively safe, the occasional presence of hazards still manifests the dangerous risk when one gets closer to the area. The limits are typically about 500-1000m away from the craters. Other travelers tried to visit for several hours without noticing danger; however, this does not mean a firm ground.

Low-Risk Zone


The percentage of volcanic risk in this zone is quite minimal. It is typically more than 1km away from volcanic vents but more than 5-10km away from crates producing moderate to intense explosive activity. This is also the zone where a false point of security leads people to build permanent structures without knowing that this is usually the part where the most evacuation and property damage happens.

Considerations for a House Structure Design

Home seekers are advised to ask for professional assistance when it comes to house design Philippines structures, considering the safety precautions to be done in building a home near a volcanic area. Design solutions help prevent injuries and worst cases, particularly in the regions that rely on bargain materials.

Evacuation Route

The most crucial part of an eruption is the evacuation plan. One must site locations beforehand that need to be selected based on practicality, methods that should be readily accessible, and windows that should efface the volcano for homeowners to look out for eruptions. Warning systems are to be considered too to alert people who might be sleeping at times if incidents.

Triple Roof Support

Volcanic ash weighs 400-700kg/m3 or more than double if saturated with rain. It means it ‘s triple the weight of the thickest snow on the roof. One must secure well-built roof support.

Concrete Structure

Researchers of Mt. Pinatubo eruption found that timber-framed buildings are more likely to fail. Concrete is suitable for wind and earthquakes associated with volcanic eruptions.

Visit our website for more details about Flatx


Leave a Reply

Your email address will not be published. Required fields are marked *