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EARTHQUAKE

EARTHQUAKE. EARTHQUAKE. EARTHQUAKE. EARTHQUAKE. EARTHQUAKE. is the perceptible shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's crust that creates seismic waves.

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EARTHQUAKE

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  1. EARTHQUAKE

  2. EARTHQUAKE

  3. EARTHQUAKE

  4. EARTHQUAKE

  5. EARTHQUAKE • is the perceptible shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's crust that creates seismic waves. • are caused mostly by rupture of geological faults, but also by other events such as volcanic activity, landslides, mine blasts, and nuclear tests. •  The seismicity or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time. • Continuing adjustment of position results in aftershocks.

  6. EARTHQUAKE • Most of the world's earthquakes (90%, and 81% of the largest) take place in the 40,000 km long, horseshoe-shaped zone called the circum-Pacific seismic belt, known as the Pacific Ring of Fire, which for the most part bounds the Pacific Plate.

  7. EARTHQUAKE • PHIVOLCSPhilippine Institute of Volcanology and Seismology is the government agency that monitors the seismic activities in our country. • Seismographan instrument that measures and records details of earthquakes, such as force and duration.

  8. EARTHQUAKE • FaultLine is a break or fracture in the ground that occurs when the Earth's tectonic plates move or shift and are areas where earthquakes are likely to occur.

  9. EARTHQUAKE • AERIAL PHOTO OF SAN ANDREAS FAULT

  10. EARTHQUAKE The point within Earth where faulting begins is the focus, or hypocenter.  The point directly above the focus on the surface is the epicenter.

  11. EARTHQUAKE • Seismologist A person who studies earthquakes. • They study earthquakes by using seismographs and by venturing into the field to view the damage caused by an earthquake. • ChangHeng invented the first seismograph in 132 A.D. and called the instrument an earthquake weathercock. 

  12. THE FIRST SEISMOGRAPH • This instrument featured eight dragons, each with a bronze ball in its mouth. Whenever a tremor occurred, a mechanism within the seismograph would cause one of the dragon's mouths to open. The ball fell into one of the toad's mouths, providing an alert for an earthquake.

  13. EARTHQUAKE • Magnitudeis the measurement of the amount of energy released during an earthquake. • The Richter Scale is a numerical scale based on the size of the largest seismic waves generated by a quake that is used to describe its magnitude.

  14. RICHTER SCALE

  15. RICHTER SCALE

  16. SEISMOGRAPH HORIZONTAL SEISMOGRAPH VERTICAL SEISMOGRAPH

  17. A SEISMOGRAPH RECORDS WAVE, AMPLITUDE, AND TIME

  18. PHIVOLCS SEISMIC MONITORING STATIONS

  19. PHILIPPINE FAULT LINE

  20. EARTHQUAKE

  21. INTENSITY SCALE • The modifiedMercalli’sscale, which measures the amount of damage done to the structures involved, is used to determine the intensity of an earthquake. • This scale uses the roman numerals I-XII to designate the degree of intensity.

  22. INTENSITY SCALE

  23. PHIVOLCS EARTHQUAKEINTENSITY SCALE (PEIS)

  24. PHIVOLCS EARTHQUAKEINTENSITY SCALE (PEIS)

  25. SHALLOW-FOCUS AND DEEP-FOCUS EARTHQUAKES • The majority of tectonic earthquakes originate at the ring of fire in depths not exceeding tens of kilometers.  • Earthquakes occurring at a depth of less than 70 km are classified as 'shallow-focus' earthquakes. • In subduction zones, where older and colder oceanic crust descends beneath another tectonic plate, Deep-focus earthquakes may occur at much greater depths (ranging from 300 up to 700 kilometers).

  26. EARTHQUAKE ENGINEERING

  27. EARTHQUAKE ENGINEERING • Branch of engineering that designs and analyzes structures with Earthquakes in mind. • Goal is to make such structures more resistant to Earthquakes.

  28. OBJECTIVES OF EARTHQUAKE ENGINEERING • Foresee the potential consequences of strong earthquakes on urban areas and civil infrastructure. • Design, construct and maintain structures to perform at earthquake exposure up to the expectations and in compliance with building codes.

  29. SEISMIC LOADING - application of an earthquake-generated agitation to a structure. Seismic loading depends on: • Anticipated earthquake's parameters at the site - known as seismic hazard • Geotechnical parameters of the site • Structure's parameters • Characteristics of the anticipated gravity waves from tsunami

  30. SEISMIC PERFORMANCE • a structure's ability to sustain its main functions, such as its safety and serviceability, at and after a particular earthquake exposure.

  31. EXPERIMENTAL ASSESSMENT • these are expensive tests that are typically done by placing a (scaled) model of the structure on a shake-table that simulates the earth shaking and observing its behavior

  32. RESEARCH FOR EARTHQUAKE ENGINEERING National Science Foundation (NSF) • is the main United States government agency that supports fundamental research and education in all fields of earthquake engineering.

  33. RESEARCH FOR EARTHQUAKE ENGINEERING Earthquake Engineering Research Institute (EERI) • a leader in dissemination of earthquake engineering research related information both in the U.S. and globally.

  34. SEISMIC VIBRATION CONTROL • a set of technical means aimed to mitigate seismic impacts in building and non-building structures. • may be classified as passive, active or hybrid.

  35. CLASSIFICATIONS OF SEISMIC VIBRATION CONTROL • Passive Control Deviceshave no feedback capability between them, structural elements and the ground. • Active Control Devicesincorporate real-time recording instrumentation on the ground integrated with earthquake input processing equipment and actuators within the structure. • Hybrid Control Deviceshave combined features of active and passive control systems.

  36. SEISMIC VIBRATION CONTROL TECHNOLOGIES Dry-stone Walls Control • mortar-free construction is proven to be apparently more earthquake-resistant than using mortar.

  37. SEISMIC VIBRATION CONTROL TECHNOLOGIES Lead Rubber Bearing • a type of base isolation employing a heavy damping. • invented by Bill Robinson, a New Zealander.

  38. SEISMIC VIBRATION CONTROL TECHNOLOGIES Tuned Mass Damper • huge concrete blocks mounted in skyscrapers or other structures and moved in opposition to the resonance frequency oscillations of the structures by means of some sort of spring mechanism.

  39. SEISMIC VIBRATION CONTROL TECHNOLOGIES Friction Pendulum Bearing • bearings that use the characteristics of a pendulum to lengthen the natural period of the isolated structure so as to avoid the strongest earthquake forces

  40. SEISMIC VIBRATION CONTROL TECHNOLOGIES Building Elevation Control • a configuration that can prevent buildings' resonant amplifications since a properly configured building disperses the shear wave energy between a wide range of frequencies.

  41. SEISMIC VIBRATION CONTROL TECHNOLOGIES Simple Roller Bearing • a base isolation device which is intended for protection of various building and non-building structures against potentially damaging lateral impacts of strong earthquakes.

  42. SEISMIC DESIGN • is based on authorized engineering procedures, principles and criteria meant to design or retrofit structures subject to earthquake exposure.

  43. FAILURE MODES • the manner by which an earthquake induced failure is observed • learning from each real earthquake failure remains a routine recipe for advancement in seismic designmethods

  44. FAILURE MODES Soft Story Effect • Occurs when a level in a multi-story building is less than 70% as stiff as the floor immediately above it, or less than 80% as stiff as the average stiffness of the three floors above it.

  45. FAILURE MODES Soil Liquefaction • where the soil consists of loose granular deposited materials with the tendency to develop excessive hydrostatic pore water pressure of sufficient magnitude and compact, liquefaction of those loose saturated deposits may result in non-uniform settlements and tilting of structures.

  46. FAILURE MODES Landslide Rock Fall • the action of gravity is the primary driving force for a landslide to occur though in this case there was another contributing factor which affected the original slope stability: the landslide required an earthquake trigger before being released

  47. FAILURE MODES Pounding against adjacent building • Pounding usually caused local damage around the impacting areas, and in extreme cases, collapse of the building structures

  48. EFFECTS OF EARTHQUAKE

  49. HUMAN INDUCED EARTHQUAKE • Hydraulicfracturing  is a technique in which high-pressure fluid is injected into the low-permeable reservoir rocks in order to induce fractures to increase hydrocarbon production. This process usually generates events that are very small to be felt at the surface (with magnitudes ranging from -3 to 0)

  50. HUMAN INDUCED EARTHQUAKE • Mining  leaves voids that generally alter the balance of forces in the rock, many times causing rock bursts. These voids may collapse producing seismic waves and in some cases reactivate existing faults causing minor earthquakes. • Extraction of fossil fuels Large-scale fossil fuel extraction can generate earthquakes. • Groundwater extraction  The changes in crustal stress patterns caused by the large scale extraction of groundwater has been shown to trigger earthquakes

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