EARTHQUAKE HAZARD Flashcards
It refers to the misalignment of the ground surface due to an earthquake
Ground rupture
Liquefaction
Liquefaction
it is only the first stage, it may result in the collapse of buildings, houses, bridges, and roads.
Ground Shaking
an overflow of water that submerges land that is usually dry
Flooding
the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction products.
Fire
FACTORS THAT AFFECT THE HAZARD OF EARTHQUAKES
- Depend on earthquake’s strength and seismic activity.
- Standard of building or house construction.
- The quality of soil or geological component.
- Depth of groundwater.
EARTHQUAKE HAZARDS ARE CLASSIFIED AS
PRIMARY EARTHQUAKE HAZARDS and SECONDARY EARTHQUAKE HAZARDS
WHAT IS GROUND SHAKING?
- First stage of earthquake hazards
- May result in the collapse of buildings, houses, bridges, and roads
- The collapse of different structures may be due to shaking or subsidence
WHAT ARE THE SECONDARY EARTHQUAKE HAZARDS ?
- arise out from the primary hazards; much disastrous.
- tsunami
- seiche
- flooding
- fire
WHAT ARE THE PRIMARY EARTHQUAKE HAZARDS ?
- ground shaking
- liquefaction
- landslide
- surface rupture
the settling of the ground due to the movement which resulted in earthquakes
SUBSIDENCE
FACTORS AFFECTING THE GROUND SHAKING AND THE WAY THE SEISMIC WAVES TRAVEL THROUGH THE GROUND:
- topography
- bedrock type
- location and orientation of the fault rupture
CLASSIFICATION OF GROUND RUPTURE
- also known as surface rupture
- refers to the misalignment of the ground surface due to an earthquake
- occurs when the split of faults spread to the earth’s surface
this may tear buildings, houses, roads, and other infrastructures into pieces - A wide ground rupture mat even swallow properties like cars
2 KINS OF SURFACE RUPTURE
DIP-SLIP FAULT and STRIKE-SLIP FAULT
THE STRENGTH OF GROUND SHAKING IS INFLUENCED BY THE FOLLOWING:
- CONDITION OF LOCAL GEOLOGY
- LENGTH OF TIME OF SHAKING AND INTENSITY OF THE EARHQUAKE
- DISTANCE
I
SCARCELY PERCEPTIBLE
- Delicately balanced objects are disturbed slightly
- water in containers oscillates slowly
II
SLIGHTLY FELT
- Felt by a few individuals at rest indoors
- Hanging objects swing slightly
- water in containers oscillates noticeably
III
WEAK FELT
- Felt by a few individuals at rest indoors, especially on the upper floors of buildings
- Vibration is felt like one passing of a light truck
- Dizziness and nausea are experienced by some people
- Hanging objects swing moderately
- water in containers oscillates moderately
IV
MODERATELY STRONG
- Felt by most people indoors and outdoors
- sleeping people are awakened, frightened, run violently
- Dining utensils clatter and clink; some are broken
- Small, light , and unstable objects may fall or overturn
- Standing motor cars may rock slightly
- liquids in containers are slightly disturbed
- water in containers oscillates strongly
- rumbling sound may sometimes be heard
V
STRONG
- Felt by most people indoors and outdoors
- sleeping people are awakened, frightened, run violently
- Dining utensils clatter and clink; some are broken
- Small, light , and unstable objects may fall or overturn
- Liquids spill from filled open containers
- standing vehicles rock noticeably
VI
VERY STRONG
- people are frightened, run outdoors and lose their balance
- motorist feels like driving with flat tires
- heavy objects/furniture move or shifted
- wall plaster may crack.
- old or poorly built houses and man-made structures are slightly damaged
- limited rock falls and rolling boulders occur in hilly to mountainous areas
- trees are noticeable shaken
VII
DESTRUCTIVE
- People are frightened and run outdoors
- people find it difficult to stand on the upper floors
- heavy objects and furniture overturn or topple
- old or poorly built structures suffer considerable damage
- well-built structures are slightly damaged
- cracks appear on dikes, fishponds, road surfaces, or concrete hollow block walls
- Limited liquefaction, lateral spreading, and landslides are observed
- trees are shaken strongly
VIII
VERY DESTRUCTIVE
- People panics, and find it difficult to stand outdoors
- railway tracks are bent or broken
- tombstones may be displaces, twisted, or overturned
- utility post, towers, and monuments may tilt or topple
- water and sewer pipes may bent, twisted. or broken
- liquefaction and lateral spreading cause man-made structures to sink, tilt or topple
- boulders are thrown out from their positions, particularly near the -epicenter
- Fissures and faults rapture may be observed
- trees are violently shaken
- Water splash or stop over dikes or banks of rivers
IX
DEVASTATING
- People are forcibly thrown to the ground
- Many cries and shake with fear
- buildings are totally damaged
- the ground is distorted into undulations
- trees are shaken very violently with some toppled or broken
X
COMPLETELY DEVASTATIN
- all man-made structures are destroyed
- massive landslides and liquefaction, large-scale subsidence and uplifting of landforms, and many ground fissures are observed
- Changes in river courses and destructive Seiche in large lakes occur
- Many trees are toppled, broken, and uprooted
What happened in July 16, 1990?
earthquake in the Northern and Central part of the Philippines, had been monitored to be an 8.7 intensity scale which is either very destructive or devastating. it caused an estimated death of around 1621 people and an estimated 369 million us dollars worth of damage
