Landslides: Types, Causes, and Safety Measures

• Geological hazards pose a threat to life and property
• They are caused by extreme natural events in the Earth's crust
• Earthquakes, volcanic eruptions, tsunamis (tidal waves) and landslides are types of geological hazards

Landslides

• Landslide is the untoward movement of stope specifically
• Can occur as a rotational slide, translational slide, block slide, topple, rockfall, debris flow, debris avalanche, earthflow, creep, and lateral spread
• Causes include; land incapability, earthquakes, volcanic eruptions, and human activity
• Landslides can be classified using Material and movement type

Safety Measures Before a Landslide

• Have an emergency kit prepared
• Plan with your household
• Sign up for your community's warning system
• Consult a professional to check your house
• Leave as soon as possible if you are advised to do so

Safety Measures During a Landslide

• Stay prepared and alert
• Indoors- Find a safe place in your house
• Outdoors- Move away from the path of falling debris
• In a car, drive safely

Safety Measures After a Landslide

• Monitor radio or TV stations for the latest emergency information
• Check if anyone has injuries
• Watch for flooding
• Report broken utility lines
• Avoid the landslide area

Sinkholes

• A sinkhole is a sunken hole from the surface to the inner part of the earth
• Sinkholes are formed by some natural or artificial phenomena
• Dissolution sinkholes occur where water first contacts limestone or dolomite
• Aggressive dissolution happens where flow is focused in openings in the rock
• Cover-subsidence sinkholes develop where covering sediments are permeable and contain sand
• Cover-collapse sinkholes may develop abruptly and cause catastrophic damages
• Can be dangerous to building foundations
• Toxic chemicals beneath the earth may come up and pollute groundwater
• Common in Florida due to underground voids and drainage systems carved from carbonate rocks
• Natural sinkholes can form on land and in the ocean
• Can change the general topography of an area and divert streams of underground water
• Some form due to leaks in underground storm drains and sewer systems
• Repairs become necessary when the sinkholes collapse
• Rainfall percolating through the soil absorbs carbon dioxide and reacts with decaying vegetation, creating slightly acidic water
• This water moves through spaces and cracks underground, slowly dissolving limestone and creating a network of cavities and voids
• As limestone dissolves, pores and cracks enlarge, carrying even more acidic water
• Heavy rains after droughts, drought, and groundwater withdrawals can make conditions favorable for sinkholes to form
• Diverting surface water from a large area and concentrating it in a single point could trigger a sinkhole
• Artificially creating ponds of surface water may lead to sinkholes
• The drilling of water wells contribute to sinkholes
• When in urban or suburban setting, sinkholes can destroy highways and buildings therefore become hazardous
• Can cause water quality problems

7 of the World's Most Stunning Sinkholes

• Fukuoka, Japan: Five lanes of road vanished in 2016 as a sinkhole nearly 100 feet wide and 50 feet deep took over
• Xiaozhai Tiankeng, China: It is the world's largest sinkhole which was discovered in 1994- double nested sinkhole includes a waterfall in its depth of over 2,100 feet
• Dean’s Blue Hole, Bahamas: circular opening is up to 115 feet in diameter widens to about 330 feet after only a drop of 66 feet which is 663ft deep
• National Corvette Museum, Kentucky: In 2014, a 60-foot by 45-foot hole lead to 8 corvettes falling 30 feet deep
• Guatemala City, Guatemala: In 2010, a 65-foot-wide hole dropped 100 feet, and killed 15 workers
• Great Blue Hole, Belize: circular diameter of nearly 1,000 feet, which is also 400 ft deep
• Guangzhou, China: A 1,000 square foot sinkhole developed in 2013 near a subway construction site.

Sinkholes In The Phillipines

• Bantayan Island and Badian, Cebu: A new sinkhole in Sta Fe town in Bantayan island was found in July
• It forced families in sitio Dapdap, Barangay Langub to relocate
• Initially, the hole was two to three feet wide but grew to 40 feet wide and 4 feet deep
• Kabankalan City, Negros Occidental: Six people reportedly fell into a newly-formed 12 foot-deep sinkhole appearing on a basketball court in Purok Jalandoni
• Baguio City: In the Phillipines sinkholes are rather common due to several known faults and numerous areas that are vulnerable to landslides
• Bohol: The deep hole found in Barangay Cambilan was because of the earthquake in October 2013
• Dadiangas, GenSan: Due to a deep hole suspected to be a sinkhole, which forced unofficial settlers to move from the community
• Only 20 dipa (fathoms) were left of the 350 fathoms of rope when attempted to measure

Sinkhole emergency- Check the Exterior of Your Property

• Examine the property, search for cracks in block and stucco
• Cracks in the properties interior, doors and windows that don't shut properly
• Sloping or uneven floors and muddy waters

Sinkhole emergency- Check Outside Your Property

• Exposed fence posts , and trees as the grounds sinks with small bare soil in the sinkhole
• Look for circular ground cracks sinking towards the sinkhole
• Notice gradual ground settlement and formation of rainfall
• Note the slumping trees and fence posts
• Be wary of interrupted plumbing or electrical services or even vegetation as it withers by water being drawn away by sinkhole

Basic sinkhole emergency preparedness

• Determine any risks you and your family/localized area has
• Familiarize yourself with emergency plans in your local community
• Develop an emergency communication plan for families and ask those out of state to serve as a family contact
• Prepare the necessary arrangements for pets and seniors
• Property preparations to reduce damage and how family shuts off water, gas, and electricity
• Provide basic CPR and first aid training
• Keep a power back up generator and/or emergency supplies on mobile
• Maintain any home inventory photo's and videos of your possessions

Guidelines

• During a sinkhole, assess the situation and evacuate.
• The best guidelines to have when an incident is to contact the emergency and all local occupants.
• Use small caution tape to prevent accidents
• Only certified/trained personnel are allowed to investigate a sinkhole; photographs can be taken as well
• Do not refill a sinkhole with trash, debris, or even waste materials; this may contaminate groundwater. Get in contact with a company that is trained to assist in this situation.

Learn about landslides, a type of geological hazard involving the movement of soil and rock. Understand the causes of landslides such as earthquakes, volcanic eruptions, and destabilization of slopes. Discover crucial safety measures to take before and during a landslide to protect life and property.