sci co2.1

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    Cards (43)

    • Earthquake
      refers to a weak to violent shaking of the ground due to sudden movement of rock material below the surface.
    • Tectonic
      sudden movement along faults and plate boundaries
    • Volcanic
      due to rising lava or magma beneath active volcanoes
    • tectonic plate boundaries
      Earthquakes primarily originate from
    • Hypocenter
      also known as focus
      it is the point inside the Earth where the earthquake originated
    • Epicenter
      the point on the Earth’s surface directly above the focus
    • PLATE TECTONICS
      Plates are large slabs of the Earth’s lithosphere that ride on a partially hot molten layer of the upper mantle or asthenosphere
      The plates tend to move in a continual slow motion, and cause interaction with its neighboring plates causing stress on margins
    • The Elastic Rebound Theory
      explains that most earthquakes are produced by the rapid release of energy stored in rocks that had been subjected to great stress
      Upon exceeding the rock strength, it suddenly ruptures,causing vibrations of an earthquake
    • Foreshock
      smaller scale earthquake that comes before a stronger earthquake
    • Mainshock
      largest scale of earthquakes in a series
    • Aftershock
      smaller-scale earthquake that comes after a larger earthquake 
      occurs as the ground tried to return to its original position after the earthquake
    • SEISMOMETER
      instrument used to measure seismic waves which may be a pendulum or a mass mounted on a spring
    • SEISMOGRAPH
      an instrument or recording device that produces a permanent record of Earth motion detected by a seismometer
    • SEISMOGRAM
      is the recording of the ground shaking at the specific location of the instrument 
    • TWO BASIC CONFIGURATIONS OF SEISMOMETERS
      VERTICAL-MOTION SEISMOMETER
      HORIZONTAL-MOTION SEISMOMETER
    • VERTICAL-MOTION SEISMOMETER
      RECORDS UP-AND-DOWN GROUND MOTION
    • HORIZONTAL-MOTION SEISMOMETER
      RECORDS BACK-AND-FORTH GROUND MOTION
    • INTENSITY
      THE EFFECT OR CONSEQUENCE OF AN EARTHQUAKE’S GROUND SHAKING AT A LOCALITY ON THE EARTH’S SURFACE
    • MAGNITUDE
      a number that characterizes the relative size of an earthquake.
      It is based on measurement of the maximum motion recorded by a seismograph
    • SCALES USED TO QUANTIFY EARTHQUAKE MAGNITUDE:
      RICHTER MAGNITUDE OR LOCAL MAGNITUDE (ML) 
      SURFACE-WAVE MAGNITUDE (MS)
      BODY-WAVE MAGNITUDE (MB)
      MOMENT MAGNITUDE (MW)
    • In 1902, an Italian scientist named Giuseppe Mercalli devised a scale for defining intensity by systematically assessing the damage that the earthquake caused
    • Note that the specification of earthquake intensity depends on a subjective assessment of damage, and of the perception of shaking, not a direct measurement with an instrument
    • RICHTER MAGNITUDE SCALE
      Developed by Charles Richter
      Based on the maximum amplitude of motion that would be recorded at a station about 100 km from the epicenter.
      The original Richter Scale works well only for shallow earthquakes that are close to the seismometer station – now called local magnitude (ML)
    • Where I stands for the intensity of the earthquake and I0 represents a zero-level earthquake the same distance from the epicenter
    • Ground Shaking
      is the disruptive up-down and sideways movement or motion experienced during an earthquake and is responsible for the collapse of structures
    • Up and down 
      first felt by people near the epicenter; not felt by people far from epicenter
    • Sideways
      felt after up and down by people near epicenter; first felt by people far from epicenter
    • Ground shaking is considered both as a hazard created by earthquakes and a trigger for other hazards such as liquefaction and landslides
      It is usually recorded in terms of intensity
    • GROUND RUPTURE
      It refers to the displacement on the ground due to movement of a fault
      Structures that are built across fault lines may experience collapse, whereas structures built adjacent to the fault may survive
    • LIQUEFACTION
      the process where the unconsolidated sediments lose grain-to-grain contact during ground shaking, thus act almost as a liquid
      In some water-saturated sediments, the water may be expelled from the spaces between grains
    • TSUNAMI
      are giant ocean waves that rapidly travel across oceans
      These sea waves are formed due to the disturbance of the ocean floor by an earthquake landslides
    • An Earthquake-induced landslide
      refers to failures in steep or hilly slopes triggered by ground shaking
      It commonly occurs in mountainous regions
    • Earthquake Hazards include:
      Ground shaking
      Ground rupture
      Liquefaction
      Tsunami
      Earthquake-induced landslide
    • STRUCTURAL EARTHQUAKE RESISTANT DESIGN
      written in the National Structural Code of the Philippines (2010)
    • Seismic Damper 
      is a device that dissipates kinetic energy
    • When seismic waves start to penetrate the base of a building structure, seismic dampers can decrease their damaging effect and improve the building’s seismic performance
    • ACTIVE CONTROL (MECHANICAL ACTUATORS) & ENERGY ABSORBER
      It utilizes the feedback from sensors measuring the response of a structure to control the behavior of structural elements through mechanical actuators
    • BRACED FRAMES
      structural systems designed to resist wind and earthquake forces
    • MITIGATION MEASURES GROUND RUPTURE
      APPROPRIATE ENGINEERING INTERVENTIONS ARE AS FOLLOWS:
      NO KNOWN SOLUTION
      NO STRUCTURE SHOULD BE BUILT EXACTLY ON TOP
      BUFFER ZONE IS 5 METERS ON BOTH SIDES OF THE FAULT
    • MITIGATION MEASURES GROUND SHAKING
      Appropriate engineering interventions are as follows:
      Structural Earthquake Resistant Design
      Base Isolation (Dampers)
      Active Control (Mechanical Actuators)
      Energy Absorber
      Braced Frames
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