Understanding Volcanic Eruptions and Volcanoes

The Philippines' formation is believed to be due to the collision of the Pacific and Eurasian plates, causing the crust to crumble.
Fault lines are cracks on the Earth's surface along which smaller plates move or slip against each other.
The focus is the place where the energy is released like an explosion.
The epicenter is the point that is immediately above the focus.
Earthquake is the weak or violent shaking of the earth's surface caused by the sudden movement of rock materials beneath it.
Active fault lines are defined by PHIVOLCS as those moving within the last 10,000 years, exhibit historical seismicity through fault slips and displacement of rocks or soil.
Magnitude is a measure of the total energy released at the earthquake's point of origin, which is below the Earth's surface.
Seismograph is the instrument that measures magnitude.
Richter magnitude scale is used to measure the strength of an earthquake.
Intensity refers to the perceived strength of an earthquake, higher intensity felt in areas closer to the epicenter.

Ground shaking
Ground rupture (displacement of the ground due to violent shaking) • Vertical displacement • Horizontal displacement
Liquefaction (increase in water pressure in saturated soil due to ground shaking)
Ground subsidence (caused by activities like extraction of groundwater, mining, and earthquakes, can cause structures to tilt or collapse)
Tsunamis (caused by earthquakes, large waves with heights of five meters or higher)

Ensure your home has a fire extinguisher, first aid kit, radio, flashlight, and extra batteries.
Learn first aid, gas, water, and electricity turns off, plan for family meetings, anchor heavy furniture, and learn earthquake plans.

Stay calm during an earthquake by staying indoors, standing against walls, and away from windows and doors.
Outdoors, stay in open spaces, away from power lines and buildings.
Avoid using matches, candles, or flames.
If in a car, stay inside until the earthquake stops.

Check for injuries, provide first aid, and shut off water, gas, and electric lines if damaged.
If gas smells, evacuate immediately and report to authorities.
Turn on the radio, stay out of damaged buildings, wear sturdy shoes, and avoid chimneys.
Stay away from beaches, follow emergency plans at school or work, and expect aftershocks.

Volcanic eruption is a natural phenomenon in which molten rock, gas, and other materials are ejected from a volcano's vent or fissure onto the Earth's surface or into the atmosphere.
A volcano is a vent on the Earth's surface that opens downward to a pool of molten rock, debris, and gases.
Its formation involves the process of subduction.

Active volcano: currently erupting or showing signs of eruption, which should have occurred within the last 600 years.
Potentially active volcano: one that has erupted and then entered a prolonged period of inactivity.
Inactive volcano: has been largely unexplored for a long time, with no recorded eruptions in the past thousand years.

Lava flow: a magma mass that flows down volcanic slopes, causing injuries and potentially burning structures and vegetation.
Pyroclastic flow: hot, dry volcanic masses moving at over 60 km/h from a collapsed eruption column, while pyroclastic surges are turbulent currents of gases, debris, and water.
Tephra falls: volcanic eruption-induced showers of fine to coarse-grained particles, causing pollution, health issues, poor visibility, and disruption of electricity and communication lines.
Ballistic projectiles: rocks released by erupting volcanoes, can land within 2 kilometers of the vent but can travel up to 5 kilometers or more if the eruption is explosive.
Volcanic gas: a key component of magma, can release harmful gases into the atmosphere, including water vapor, hydrogen sulfide, sulfur dioxide, carbon monoxide, hydrogen chloride, and hydrogen fluoride.
Lahar: a mixture of volcanic debris and water, can be hot or cold, and can destroy structures and communities due to volcanic eruptions or heavy rainfall.

Landslides are geological phenomena involving the downward movement of soil, rocks, or debris along a slope, triggered by factors like gravity, heavy rainfall, earthquakes, and volcanic activity.
Human activities like mining, deforestation, and construction of buildings negatively impact land surface, exposing and destabilizing the ground, which can lead to natural disasters and landslides.

Creep: a flow or gradual movement of soil
Slump: the downslope flow of soft and unconsolidated materials
Rockfall: the free falling movement of massive rocks from a cliff or sleep slopes
Debris flow: the rapid flow of debris and other rock materials
Mudflow: characterized by a flowing mass of mud along the flank of a volcano

Increase in the frequency of volcanic quakes with rumbling sounds, occurrence of volcanic tremors
Increased steaming activity; change in color of steam emission from white to gray due to entrained ash
Crater glow due to presence of magma at or near the crater
Ground swells (or inflation), ground tilt and ground fissuring due to magma intrusion
Localized landslides, rock falls, and landslides from the summit area not attributable to heavy rains
Noticeable increase in the extent of drying up of vegetation around the volcano's upper slopes
Increase in the temperature of hot springs, wells, and crater lake near the volcano
Noticeable variation in the chemical content of springs and crater lakes within the vicinity of the volcano
Drying up of springs/wells around the volcano