The Philippine Online Chronicles

As the string of -Ber months approaches, Filipinos are braced for the horrors that usually come with heavy rains. After all, how can we ever survive another Ondoy? The said tragedy has left us fearful and for a good reason.

Last month, Science Undersecretary Graciano Yumul gave warning that the La Niña weather may bring with it residual effects such as "Ondoy-like rains". Usec Yumul is the person who oversees the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).

As a precaution, Environment Secretary Ramon Paje said that government local officials should listen to PAGASA's warnings of heavy rains to come, adding that officials should "familiarize themselves with geohazard maps" to mark areas which are most likely to experience flooding and landslides.

But what are geohazard maps and how exactly can they help us prepare for the tempest?

Wikipedia defines geohazard as a “geological state that represents or has the potential to develop further into a situation leading to damage or uncontrolled risk.” In addition, geohazards are related to geological and environmental conditions and involve long-term and/or short-term geological processes.

Examples of geohazards include:

• Landslides

• Debris flows

• Shallow gas accumulation

• Over-pressured zones (including gas and shallow water flows)

• Naturally occurring gas hydrates and their climate-controlled meta-stability

• Mud flows, diapirism and mud volcanism/mud volcanoes

• Earthquakes and seismicity

• Tsunamis from tectonics and landslides

• Rock falls and landslides

How can geohazard maps help us survive natural disasters?

The study of occurrence and implications of geohazards has the potential of saving lives which are otherwise lost due to various geologic disasters like that of the 1991 Pinatubo Volcano eruption, or the 1999 landslides at the Cherry Hills and so many others. Information contained in geohazard maps warn people of the peril that awaits them.

In the Philippines, the Mines and Geosciences Bureau (MGB) is the agency that declares locations that are highly susceptible to geohazards. It was in 2004 that a National Geohazard Mapping Program began identifying areas that are prone to such disasters. The MGB has completed the geohazard assessment and mapping of the country and has distributed geohazard maps with a scale of 1:50,000 to local governments.

MGB also started making digital copies of geohazard maps so it can be accessible to more people. These digital versions are said to include “satellite imagery of various layers of images outlining the country’s topographical, geological and coastal features.” All digital geohazard maps are estimated to be completed this year, but about 98 geohazards maps, or 50 percent of the total maps, are already posted on the MGB website.

According to the MGB, the following are the top 10 most flood-prone areas: Metro Manila, Pampanga, Nueva Ecija, Pangasinan, Tarlac, Maguindanao, Bulacan, North Cotabato, Oriental Mindoro and Ilocos Norte.

Flood-prone provinces along the Eastern Seaboard include: Cagayan, Isabela, Aurora, Camarines Norte, Camarines Sur, Northern Samar, Eastern Samar, eastern side of Leyte, Surigao del Norte, Surigao del Sur, Agusan del Sur and Davao Oriental.

Landslide-prone areas in Northern Luzon are: Benguet, Mountain Province, Nueva Vizcaya, Kalinga, Apayao, Southern Leyte, Abra, Marinduque, Cebu, Catanduanes and Ifugao.

Such vital information can be used by the local government primarily to get people out of danger zones, with simple actions like prohibiting the construction of residential areas in problem areas. By using technology in similar ways, we can all make it through the rain.

Photo from DENR website. Some rights reserved.