NATURAL HAZARD Flashcards
a natural process and event that is a potential threat to human life and property
natural hazard
3 types of natural hazard
Geologic Hazards
Hydrometeorological Hazards
Coastal Hazards
a hazardous event that occurs over a limited time span in a defined area.
disaster
a massive disaster that requires significant expenditure of money and a long time (often years) of recovery to take place
catastrophe
- used to describe the complex interactions between the component sub-cycles of tectonic, rock, hydrologic and biogeochemical cycles
Geologic cycle
– involves the creation, movement, and destruction of tectonic plates
Tectonic cycle
– the largest of the geologic sub-cycles, and is linked to other sub-cycles.
Rocks cycle
is a natural geologic event that can endanger human lives and threaten human property.
geological hazard
is the trembling of the Earth’s surface that occurs when the energy in the form of strain in rock layers is released.
earthquake
Basic Earthquake Features:
- epicenter
- hypocenter
– place on the surface of the earth above where the ruptured rocks broke up to produce an earthquake
Epicenter
– directly below the focus. The point of initial breaking or rupturing within the earth
Hypocenter (focus)
Earthquakes are measured and compared by:
- intensity
- magnitude
- moment magnitude
- ritcher scale
- effects of ground motion on people and structure
Intensity
- amount of energy an earthquake released
Magnitude
– indicates the size of the earthquake with a decimal number.
Moment magnitude
– developed by famous seismologist Charles Ritcher
-Still used by some news reporters
Ritcher Scale
is a number which is measure if energy released in an earthquake
magnitude
is a measure of the strength of shaking during the earthquake
intensity
Effects of earthquakes and linkages with other natural hazards
- Shaking and ground rupture
- liquefaction
- Regional changes in land elevation
- landslides
- fire
- disease
is a downslope movement of a mass of rock, debris, earth, or soil (soil being a mixture of earth and debris). A slope is a slant or incline on a land surface.
landslide
– mineral composition, degree of cementation or consolidation, the presence of zones of weaknesses
Earth material
– Topographic relief refers to the height of the hill or the mountain above the land below.
Topography and slope angle
– weather that is typical in a place over a period of years or decades.
Climate
– all the plants or plant life in a place.
Vegetation
is caused by spreading and sinking of lithospheric plates at plate boundaries that interact with other earth materials that produce magma.
Volcanic activity
- molten rock under the earth’s crust
Magma
- molten rock erupted by a volcano to the earth’s surface
Lava
– opening of a volcano through which lava and other volcanic materials are extruded onto the surface
Vent
is an area where large number of earthquakes and volcanic eruptions occur in the basin of the Pacific Ocean.
Ring of Fire
Classifications of volcanoes according to activity:
- active
- dormant
- extinct
- currently erupting or showing signs of unrest (earthquakes, gas emissions)
Active
– currently not active, but could become active again
Dormant
– considered unlikely to erupt again
Extinct
– Initiative may come from government officials or the National Disaster Risk Reduction Management Council.
Earthquake hazard reduction program
is a process or phenomenon of atmospheric, hydrological or oceanographic nature that can endanger human lives and threaten human property
Hydrometeorological hazard
Coined form the Greek word meaning “coil of snake”
•An area or center of low atmospheric pressure characterized by rotating winds
cyclones
•In the Atlantic and Pacific Oceans
•After a Caribbean word for evil god of winds and destruction
Hurricanes
•in the Pacific Ocean west of International Dateline
•“scary wind” or “wind from four directions”
Typhoons
is a general term for large thunderstorm complexes rotating around an area of low pressure that has formed over warm tropical or subtropical ocean water.
tropical cyclone
are called tropical depressions and tropical storms.
Low intensity tropical cyclones
are hurricanes/typhoon.
High intensity tropical cyclone
– a large area of unsettled weather that is typically 200 to 600 km in diameter and has an organized mass of thunderstorms that persists for more than 24 hours.
Tropical disturbance
– a tropical disturbance may become a tropical depression if winds increase and spiral around the area of disturbed weather to form a low-pressure center.
Tropical depression
– once maximum sustained wind speeds increase to 63 km per hour, the depression is upgraded to a tropical storm and receives a name.
Tropical storm
– if winds of a tropical storm increase in speed, it becomes a hurricane/ typhoon.
Hurricane/typhoon
– clouds that spiral around the hurricane/typhoon
Rainbands
– innermost band of clouds that has the most intense winds
Eyewall
•a shift in winds that often causes a very rainy season or a very dry season.
Monsoon
– from November to February. Gives cold temperatures and causes much rainfall over the eastern coast of the Philippines.
Northeast Monsoon
– from July to September. Responsible for a great amount of rainfall during our wet season.
Southwest Monsoon
– winds that reliably blow east to west just north and south of the equator.
Trade winds
•The natural process of a river’s overbank flow is termed
.
flooding
– any natural stream of water that flows in a channel
with defined banks (larger stream)
River
– any natural stream of water that flows in a channel
with defined banks (larger stream)
River
– any body of water that flows in channel
Stream
– region drained by a single stream or river.
Drainage Basin
- water from rain or snow that flows over the surface of the ground into streams
Runoff
– produced by intense rainfall of short duration over a relatively small area
Flash floods
– cover a wide area and are usually produced by storms of long duration that saturate the soil and produce increased runoff
Downstream floods
- injury, loss of life; damage caused by swift currents, debris, and sediment to farms, homes buildings, railroads, bridges, roads, and communication systems.
Primary effects:
(caused by disruption and malfunction of services and systems because of flood): short term pollution of rivers, hunger and disease, and displacement of persons who have lost their homes.
Secondary effects
•A small-diameter column of violently rotating air developed within a convective cloud and in contact with the ground.
Tornado
are created by a wide variety of coastal processes.
Coastal landforms
– is defined as “the group of processes whereby debris or rock material is loosened and dissolved” (Thomas and Goudie, 2000).
Erosion
•Storm surge is the local rise of sea level that results primarily from water that is pushed toward the shore by wind that swirls around a storm.
Storm surge
two (2) mechanisms that cause the storm surge during an intense cyclone:
(1)stress exerted by wind on the water surface; and (2) low atmospheric pressure in the storm that pulls the sea surface.
