Volcanic Hazard: West Valley Fault 'The Big One'

Study Notes

Volcanic hazards include lahars, ash fall, pyroclastic flows, projectiles, poisonous gases, and lava flows.
Preparation is crucial for those living near active volcanoes, as eruptions can occur with little warning.

The West Valley Fault is a key fault line marking potential earthquake zones in the Philippines.
"The Big One" refers to a predicted intense earthquake scenario with significant destructiveness.
Length of the West Valley Fault is approximately 100 km, affecting multiple cities including Quezon City, Marikina, and parts of Cavite.
The fault can potentially generate a 7.2 magnitude earthquake, causing intensity 8 shaking in Metro Manila.

Estimated casualties include 37,000 fatalities and 140,000 serious injuries from a 7.2-magnitude quake.
Anticipated economic damage is around P2.5 trillion.
Approximately 40% of buildings and homes in Metro Manila could be compromised.
Around 500 fires could be triggered, resulting in an additional 18,000 deaths.

Lahar: Flow of volcanic debris and materials into rivers or valleys, often triggered by heavy rainfall.
Ash Fall: Dust and particles from explosive eruptions can damage structures and create hazardous conditions.
Pyroclastic Flow: Fast-moving currents of gas and volcanic matter that can incinerate everything in their path.
Ballistic Projectiles: Solid rocks (blocks) and partially molten rocks (bombs) thrown from a volcano during eruptions.
Poisonous Gases: Eruptions release toxic gases like hydrogen sulfide and sulfur dioxide, contributing to acid rain.
Lava Flow: Molten rock that flows from a volcano, generally slower than pyroclastic flow, allowing for evacuation.

Stay informed through local news and updates on volcanic activity.
Familiarize yourself with your community’s emergency response plans and warning systems.