Thursday, December 25, 2008

FAULTS (EARTHQUAKE) IMPACT TOWARDS BUILDING FOUNDATION

A fault is a fracture in the crust of the earth along which rocks on one side have moved relative to those on the other side. Most faults are the result of repeated displacements over a long period of time.

TYPES OF FAULT;
1. Dip Slip Faults
The movement is up or down parallel to the dip of inclined faults surface



2. Strike slip fault

A fault where movement(or slip) is predominantly horizontal and therefore parallel to the strike of the fault
3. Oblique-Slip Fault
A fault where movement of both strike-slip and dip-slip components

IMPACTS OF FAULT
Earthquake-induced ground shaking can pose threats to people and structures (specially foundation of the building which leads to collapse the buildings) even at distant locations from the fault on which the earthquake event is occurring. Ground shaking at a particular location depends on the earthquake magnitude (e.g., a measure of total energy released by fault rupture); epicenter distance (e.g., the distance from the center of the fault rupture to the location of interest); and, subsurface conditions of the geologic and soil units at the location of interest.
EFFECTS OF EARTHQUAKE TOWARDS BUILDING FOUNDATION

Ground motion

  • Is the trembling and shaking of the land
  • can cause building to vibrate
  • can be large enough to topple large structures such as bridges and office and apartment buildings
Landslide
  • can be triggered by shaking of the ground
  • can cause extensive damage
Liquefaction
  • occurs when a water saturated soil or sediments turns from a solid to a liquid as a result of earthquake shaking
  • causes building to sink and underground tanks to float as once-solid segments flow like water.
LOCATING AND MONITORING
Earthquakes can be monitored using the instrument that could accurately record seismic waves. The instruments measure the ground motion and can be use to find the location, depth and size of an earthquake.
- seismometer
- seismograph
- seismogram

MINIMIZE BUILDING FAILURE
  • construction must meet the building codes(strictly enforced in earthquake-prone areas)
  • control the location of the buildings.(building built on soft sediment are damaged more than building on hard rock)
  • firmly attach house to the foundation with anchor bolts.
  • Repair any deep cracks in foundations

No comments:

Post a Comment