Geological Hazards, Fire Hazards and Hydrometeorological Hazards Lecture Notes

Flashcards covering geological hazards, fire hazards and hydrometeorological hazards.

Landslide

The downward movement of soil, rock, and debris due to gravity.

Rainfall-induced landslides

Caused by heavy rainfall that increases the weight of the soil and reduces its cohesion.

Causes of rainfall-induced landslides

Excessive rainfall saturates the soil. Weak or unconsolidated soil or rock layers. Steep slopes or mountainsides.

Signs of impending landslides

Cracking of walls, floors, or roads. Soil erosion at the foot of slopes. Water pooling in unexpected areas.

Impact of rainfall-induced landslides

Loss of lives and injuries. Destruction of homes and infrastructure. Disruption of transportation and communication systems. Damage to agricultural lands.

Early Warning Systems (Landslides)

Use rainfall intensity monitoring and slope stability assessment.

Proper Drainage Systems (Landslides)

Prevent water from accumulating in vulnerable areas.

Soil Stabilization (Landslides)

Plant grass and trees to reduce soil erosion.

Land Use Planning (Landslides)

Avoid construction in high-risk landslide areas.

Sinkhole

A depression or hole in the ground caused by the collapse of a surface layer, often resulting from underground erosion or the dissolution of soluble bedrock (like limestone).

Natural cause of Sinkholes

Erosion of limestone, gypsum, or other soluble rocks by water.

Human cause of Sinkholes

Over-extraction of groundwater, drilling, or construction.

Signs of impending sinkholes

Cracking in roads, foundations, or sidewalks. Sudden appearance of depressions in the ground. Changes in the flow of underground water.

Impact of Sinkholes

Collapsing of roads and buildings. Submergence of agricultural lands. Disruption of utilities like water, gas, and electricity. Potential loss of life.

Groundwater Management (Sinkholes)

Monitor and control the extraction of groundwater.

Geotechnical Investigations (Sinkholes)

Conduct site assessments before construction.

Land Use Regulation (Sinkholes)

Restrict development in sinkhole-prone areas.

Awareness and Education (Sinkholes)

Inform communities of sinkhole risks and signs.

Fire Triangle elements

Fuel, Heat, Oxygen

Fuel

Any combustible material (e.g., wood, fabric, gasoline).

Heat

An energy source that raises the material to its ignition temperature.

Oxygen

Typically available from the atmosphere.

Common Causes of Fires in the Philippines

Defective electrical wiring and improper use of appliances; Negligence in cooking (e.g., unattended stoves); Improper disposal of smoking materials; Storage of flammable substances near heat sources; Intentional fires (arson).

Precautionary Measures to Prevent Fires

Regular maintenance of electrical systems; Responsible use of cooking and heating equipment; Proper storage of flammable materials; Installation and regular testing of fire alarms and extinguishers; Participation in fire drills and safety orientations.

Incipient Phase of a Fire

The fire starts; early suppression is possible.

Growth Phase of a Fire

Fire spreads; structural conditions deteriorate.

Fully Developed Phase of a Fire

Maximum combustion; highest threat to life and property.

Decay Phase of a Fire

Fire diminishes, but hazards from toxic gases and weakened structures remain.

R.A.C.E. (Basic Response Procedures During Fire Emergencies)

Rescue, Alarm, Contain, Evacuate

P.A.S.S. Method (Proper Use of Fire Extinguishers)

Pull the pin; Aim low at the base of the fire; Squeeze the handle; Sweep side to side.

Fire Emergency and Evacuation Planning elements

Clear identification of evacuation routes and exits; Assembly points located at safe distances; Regularly conducted fire drills; Clear accountability systems for ensuring all individuals are evacuated safely.

Typhoon (Bagyo)

A severe tropical cyclone characterized by strong winds and heavy rainfall.

Typhoon Categories (PAGASA)

Tropical Depression, Tropical Storm, Severe Tropical Storm, Typhoon, Super Typhoon

Signs of Impending Typhoon

Intensifying rain and wind, Sea level disturbances, Weather advisories from PAGASA.

Typhoon Monitoring Tools

PAGASA Typhoon Bulletin, Project NOAH, Hazard Hunter PH

Thunderstorm

Localized storm producing lightning, thunder, heavy rain, and sometimes hail.

Signs of Impending Thunderstorm

Dark, towering cumulonimbus clouds, Sudden drop in temperature, Static in radio transmissions.

Thunderstorm Monitoring Tools

PAGASA Thunderstorm Advisory, Weather Monitoring Apps

Flash Flood

A rapid flood occurring within minutes or hours after heavy rainfall or dam failure.

Signs of Impending Flash Flood

Continuous heavy rainfall, Rapid rise of water in streams and streets.

Flash Flood Monitoring Tools

Flood Hazard Maps from DOST-PAGASA, Flood Warning Systems in LGUs

Flood (Baha)

Overflow of water submerging normally dry land. Can result from typhoons, thunderstorms, prolonged rains.

Signs of Impending Flood

Overflowing rivers and canals, Continuous moderate to heavy rainfall, Early warnings from local government units.

Flood Monitoring Tools

Hazard Hunter PH, PAGASA Rainfall Advisories

Storm Surge

An abnormal rise in sea level during tropical cyclones due to strong winds pushing water toward the shore.

Signs of Impending Storm Surge

Coastal waterline receding or rapidly advancing, High waves even without visible storm yet.

Storm Surge Monitoring Tools

Storm Surge Advisory (SSA) by PAGASA, NOAA Wavewatch Models, Hazard Mapping by LGUs

El Niño

A prolonged warming of the central and eastern Pacific Ocean.

Signs of El Niño

Unusual dry spells, Below normal rainfall over extended periods.

El Niño Monitoring Tools

ENSO Advisories by PAGASA, Seasonal Climate Outlooks

La Niña

A prolonged cooling of the Pacific Ocean.

Signs of La Niña

Early onset of rainy season, Frequent low-pressure systems and thunderstorms.

La Niña Monitoring Tools

La Niña Watch/Alert by PAGASA, Weather Advisory Bulletins

Key Features of Hydrometeorological Hazard Maps

Color-coded severity levels, Legend indicating hazard types, Geographic coordinates and high-risk zones.