DRRR: Q4 LESSON 3-4: EXAM REVIEWER

• Tsunami


  A phenomenon where a series of strong waves that are responsible for the surge in water sometimes reach the heights in many meters
• Tsunami


  • Caused due to volcano eruption in the ocean beds
  • Caused by landslides and earthquakes
  • Has a huge impact
• Tsunami is also called as the series of ocean waves that have a very long wavelength
• Highest recorded tsunami

  524 meters in height, occurred in 1958 in Alaska
• Tsunami waves generated in lakes or bays do not travel for a long distance and are not as destructive as the ones produced in the ocean waters
• Countries affected by 2004 Indian Ocean tsunami

  • Thailand, India, Indonesia, Sri Lanka, Bangladesh, Maldives
• The most important earthquake belt is the Circum-Pacific Belt, which affects many populated coastal regions around the Pacific Ocean
• Landslide


  A massive outward and downward movement of slope-forming materials
• Landslide


  • Triggered by prolonged heavy rainfall or other sources of water which increase the water content of the slope materials
  • Caused by earthquake or volcanic eruption
• Types of landslides

  • Slides (rotational and translational)
  • Falls
  • Topples
  • Flows (debris flow, debris avalanche, earthflow, mudflow, creep)
  • Lateral spreads
• Sinkhole


  An area of ground that has no natural external surface drainage, where water stays inside and drains into the subsurface
• Tsunami


  A phenomenon where a series of strong waves that are responsible for the surge in water sometimes reach the heights in many meters
• Tsunami


  • Caused due to volcano eruption in the ocean beds
  • Also caused by landslides and earthquakes
  • Has a huge impact
• The term tsunami is associated with tidal waves
• Tsunami


  • A series of ocean waves that have a very long wavelength
  • Causes inland movement of water which is very high and lasts for a long time
  • The impact of these waves is also very high
• The highest ever recorded tsunami was on 9th July 1958 in the record books. It took place in a bay which was located in the ligula bay along the coasts of Alaska. After the quake, a massive mass of rock fell into the bay waters from the cliff nearby. Thus, this created an impact and produced a wave that reached a height of 524 meters. Also, this is regarded as one of the highest recorded tsunami waves ever.
• Tsunami waves that are generated in the lakes or bays do not travel for a long distance. Thus, they are not as destructive as the ones produced in the ocean waters.
• 2004 India tsunami

  • ORIGIN: Indonesia
  • DEAD: 200,000
  • TSUNAMI WAS FELT TO COUNTRIES LIKE Thailand, India, Indonesia, Sri Lanka, Bangladesh, and Maldives
• The most important earthquake belt is the Circum-Pacific Belt, which affects many populated coastal regions around the Pacific Ocean—for example, those of New Zealand, New Guinea, Japan, the Aleutian Islands, Alaska, and the western coasts of North and South America.
• Landslide


  A massive outward and downward movement of slope-forming materials
• Landslide


  • Triggered by other natural hazards such as prolonged, heavy rainfall or by other sources of water which increase the water content of the slope materials
  • Caused by earthquake or volcanic eruption
• Slides


  Mass movements where there is a distinct zone of weakness that separates the slide material from more stable underlying material
• Falls


  Abrupt movements of masses of geologic materials, such as rocks and boulders, that become detached from steep slopes or cliffs
• Topples


  Failures distinguished by the forward rotation of a unit or units about some pivotal point, below or low in the unit, under the actions of gravity and forces exerted by adjacent units or by fluids in cracks
• Types of flows

  • Debris flow
  • Debris avalanche
  • Earthflow
  • Mudflow
  • Creep
• Debris flow


  A form of rapid mass movement in which a combination of loose soil, rock, organic matter, air, and water mobilize as a slurry that flows downslope
• Debris avalanche

  A variety of very rapid to extremely rapid debris flow
• Earthflow


  Have a characteristic "hourglass" shape. The slope material liquifies and runs out, forming a bowl or depression at the head. The flow itself is elongate and usually occurs in fine-grained materials or clay-bearing rocks on moderate slopes and under saturated conditions.
• Mudflow


  An earthflow consisting of material that is wet enough to flow rapidly and that contains at least 50 percent sand-, silt-, and clay-sized particles
• Creep


  The imperceptibly slow, steady, downward movement of slope-forming soil or rock, caused by shear stress sufficient to produce permanent deformation, but too small to produce shear failure
• Lateral spreads


  Usually occur on very gentle slopes or flat terrain. The failure is caused by liquefaction, the process whereby saturated, loose, cohesion less sediments (usually sands and silts) are transformed from a solid into a liquefied state.
• Sinkholes


  An area of ground that has no natural external surface drainage – when it rains, all of the water stays inside the sinkhole and typically drains into the subsurface
• Types of sinkholes

  • Dissolution sinkholes
  • Cover-subsidence sinkholes
  • Cover-collapse sinkholes
  • Human-induced sinkholes
• Dissolution sinkholes


  Formed by the dissolution of the limestone or dolomite, most intensive where the water first contacts the rock surface and where flow is focused in preexisting openings in the rock
• Cover-subsidence sinkholes


  Tend to develop gradually where the covering sediments are permeable and contain sand
• Cover-collapse sinkholes


  May develop abruptly (over a period of hours) and cause catastrophic damages, occurring where the covering sediments contain a significant amount of clay
• Human-induced sinkholes


  New sinkholes correlated to land-use practices, especially from groundwater pumping and from construction and development practices, as well as changes to natural water-drainage patterns and the substantial weight of new material