DRRISK080

• A volcano is a vent that connects molten material (magma) from the Earth's crust to the Earth's surface
• Parts of a volcano

  Ash Cloud, Vent, Side Vent, Parasitic cone, Lava and ash layers, rock layers, Throat, Lava flow, Crater, Silt, Conduit, Branch Pipe
• Classification of volcano

  1. Active - is currently erupted or has erupted within the last 600 years
  2. Potentially Active - has erupted and entered a long period of inactivity
  3. Inactive - has not shown any sign of activity and has not erupted for the last 1000 years
• Subduction - plates sink for as deep as 80-160 km. The fluid and minerals that melt produce magma. And when the pressure builds up inside the chamber plus the accumulation of gases, an eruption would happen
• PHIVOLCS (Philippine Institute of Volcanology and Seismology) - is a service institute of DOST who are mandated to mitigate disasters from volcanic eruptions, earthquakes, tsunamis, etc.
• Styles of Volcanic Eruption

  1. Effusive - magma leaks out onto the surface passively as lava flows
  2. Explosive - escaping gas bubbles rip apart the magma fragmenting it.
• The first explosion on june 7, 1991, where it generated column of ash 7km high

  Expelled: 10B tons of magma and 20B tons sulfur dioxide
• Mt. Pinatubo has a 34km high eruption column
• VOLCANIC HAZARDS

  Pyroclastic flow - hot dry masses of fragmented volcanic materials

  Volcanic gas - one of the basic components of magma.

  Pyroclastic surges - turbulent concentration density current of rock debris, gases, and water

  Ashfall - fine to coarse grained volcanic materials

  Lava flows - mass of magma that goes down the slope of a volcano

  Ballistic Projectiles - rocks released into the air

  Lahar - mixture of water to volcanic debris

  Hot lahar - directly caused by the volcanic eruption

  Cold lahar - caused by heavy rain
• Landslide - the downward movement of rocks, soil, and Earth materials along a slope.
• Creep - the slow, gradual movement of soil

  Slump - the downslope flowage of unconsolidated materials.

  Rock and slide debris - slow to rapid movement of soil and rock materials.

  Mudflow - mass movement characterized by a mass of flowing mud along the flank of a volcano.
• Tiltmeter - measures very small changes along the vertical level.
• Sinkhole - a hole that sinks.

  Causes: erosion on bedrocks, acidic rain, mining and drilling, and ground failure
• Solution sinkhole - connected to conduit, forming a submerine spring. it is plugged at its base to form saltmarsh pond. It is connected to an underlying cave to form freshwater lake and is formed from a fracture.
• Cover-collapse sinkhole - formed by collapse of cover sediments into a large cavern in a bedrock.
• Cover-subsidence sinkhole - formed by settling of cover sediments into solution pipes and fractures.
• Sinkholes swallow houses and roads, drain streams, lakes, and other forms of wetland.

  what to do? AVOID IT.
• Typhoon

  Tropical cyclone - an intense low pressure system with a minimum sustained wind velocity oof 35km/hr

  Agencies

  PAGASA - the source of information about tropical cyclones even before it enters the Philippine area of responsibility.
• Tropical depression - 61kph below

  Tropical cyclone - 62kph - 88kph

  Severe tropical cyclone - 89kph - 117kph

  Typhoon - 118kph - 220kph

  Super typhoon - 220kph above
• Executive order no. 66, s. 2012 has rules about the cancellation of classes.

  SIGNAL 1 - kindergarten

  SIGNAL 2 - kindergarten, elementary, high school

  SIGNAL 3 - kindergarten to college
• signal 1 - a tropical cyclone will enter the locality.

  signal 2 - a moderate tropical cyclone will enter the locality.

  signal 3 - a strong tropical cyclone will enter the locality.

  signal 4 - an intense typhoon will enter the locality.
• The LGU (local government unit) has the authority to declare local suspensions in areas where there is no storm signal
• Flood - overflowing of water
• River flood - occurs when water exceeds the capacity of channels

  Flash floods - caused by a short period of unusually heavy rainfall.

  Coastal flood - occurs when strong onshore wind pushes water to inland
• Flood causes

  Prolonged raainfall, overflowing of rivers and lakes, storm surge, high tide, deforestation, etc
• RED rainfall advisory

  above 30mm rain observed in 1 hour and will continue for the next 2 hours. Serious flood; RESPONSE: EVACUATE
• Orange rainfall advisory

  15mm to 30mm rain. Flood is threatening; RESPONSE: ALERT FOR EVACUATION
• Yellow rainfall advisory

  7.5mm to 15mm rain observed in 1 hour and expected to continue for the next two hours. RESPONSE: MONITOR weather conditions
• Storm surge - the sudden rise of sea levels above the normal level on the coast due to force of winds

  1. wave can reach up to 18ft high
  2. can go as far away as 2km away from shoreline
  3. compared to tsunamis but is different
  4. causes flooding, especially when it coincides with high tide
• Thunderstorm - violent rainstorm that produces thunder, lightning, and hail

  1. warm moist air moves over the ocean
  2. water vapor rises into the atmosphere
  3. as water vapor rises, it cools and condenses into liquid droplet
  4. condensation releases heat into atmosphere, making the air lighter
  5. the warmed air continues to rise with moist air from the ocean, taking its place and producing more winds. thus, precipitation will happen.
• Stages of thunderstorm

  Initial stage - warm air rises and water vapor condenses to cumulus clouds.

  Mature stage - the cloud causes heavy precipitation lightning rain and tornadoes can be seen.

  Dissipating stage - precipitation decreases.
• Thunderstorm hazards

  Lightning - the occurrence of a natural electrical discharge of very short duration and high voltage between cloud and the ground or within ground. It is the most dangerous due to its high voltage.


  Tornadoes - a mobile, destructive vortex of violently rotating winds having appearances of funnel-shaped cloud and advancing beneath large storm system.

  Hailstone - icy crystals

  Heavy rain - floods
• Bomb threat - verbal or written, to detonate an explosive or incendiary device to cause property damage.
• Bombs can be constructed to look like almost anything and can be placed or delivered in any number of ways. The probability of finding a bomb that looks like a stereotypical bomb is almost non-existent
• The Bomb Joke Law (presidential decree 1727, 1980)

  penalizes those communicating false information on attempts to damage or destroy properties through explosivs.

  imprisonment of not more than 5 years and a fine of not more than p40,000
• Low level response - include notification of staff with instructions to be vigilant of unusual building activities or suspicious individuals. Law enforcements should be notified because any type of bomb, regardless of degree of credibility, is a criminal offense.
• Medium level response - includes steps from low level response as well as possible evacuation of employees or simply leaving them in their existing locations. Response by emergency service is expected. Walkthrough of authorities may include room to room examination.
• High level response - involves steps from low and medium response. However, this time, a full evacuation would be warranted and not over reactionary. Law enforcements would treat the building as a crime scene. Preparation for a search of tower using special equiments is necessary.
• The Philippine Disaster Risk Reduction and Management Act of 2010 (R.A. 10121) - a new law which transforms the PH disaster management system from disaster relief and response towards disaster risk reduction.
• In the past 20 years, 31,835 filipinos have been killed and 94,369,462 people have been affected by disasters.