Volcanic Eruption Process and Types of Volcanoes

Lahars are most dangerous when they are wet and fluid, allowing them to travel further and spread more destructively.

Ash fall poses danger to airplanes because volcanic ash can clog their engines, causing them to malfunction.

Excessive ash fall destroys crops, making them inedible and unproductive.

Pyroclastic flow is the collective name for hot, fast-moving volcanic materials (ash, rocks, gases) that erupt explosively from a volcano.

Ash fall causes breathing problems and environmental cooling as fine volcanic particles spread widely.

Ash fall is made up of fine-grained volcanic materials like rock fragments and minerals.

Lava is molten material that erupts from a volcano.

Active volcanoes, according to PHIVOLCS, have erupted within historical past and have records of activity.

A lahar is a type of mudflow or debris flow formed by the mixing of pyroclastic materials with water from rainfall or volcanic sources.

Pyroclastic materials are various forms of matter ejected from a volcano during eruption.

A vent in the Earth's crust where magma rises from the depths and erupts.

Inactive volcanoes have undergone significant alterations from weathering and erosion, changing their original shape.

Radon is a type of noble gas.

Before earthquakes, radon emissions in soil and groundwater usually increase.

Earthquake swarms are frequent, short-term, similar-depth minor movements.

Landslides and slope failure differ in the process involved (mass-wasting vs. fracture).

An aquifer is a rock formation that contains groundwater.

Studying earthquake trends attempts to predict the timing of the next large earthquake.

Seismic waves are caused by the release of energy stored in the Earth's rocks during an earthquake.

Ground rupture is the breaking or fracturing of the Earth's surface or rocks due to seismic activity.

Increased water pressure in the soil during an earthquake reduces the effective stress between soil particles, weakening it.

Subsidence is the process of the ground sinking or developing a depression.

One effect of liquefaction is ground subsidence.

Subsidence can form lakes.

Pyroclastic flows can travel at speeds up to 700 kph.

Rocks and gas inside pyroclastic flows have temperatures from 200°C to 700°C.

The topography of the surrounding area affects the direction of a pyroclastic flow.

A pyroclastic surge is a turbulent rush of hot gases and materials above the pyroclastic flow.

Blocks and bombs are pyroclastic fragments larger than 64 mm.

Approximately 30,000 inhabitants died when Mt. Pelee erupted on May 8, 1902.