![]() Liquefaction occurs up to a certain depth of the soil and hence if we are able to pre-determine the potential and the possible depth of liquefaction, building foundations can be designed to go below the liquefiable depth and can remain unaffected in earthquake shaking. This can result in major damage during earthquakes. Liquefaction takes place when loosely packed, saturated sediments at or near the ground surface lose their strength in response to strong ground shaking, and flow like a thick fluid. Learning about potential tsunami hazard is essential in coastal areas with high or medium earthquake risk. Historical records may also contain accounts of secondary hazard events triggered by past earthquakes. Maps may exist that describe the extent of tsunami inundation, liquefaction, or land-sliding. ![]() Obtain information on these hazards from the government agency responsible for emergency management. Engineers need this additional information to design the facility properly.Įarthquakes can cause secondary hazards that include fires, landslides, liquefaction (see definition below), floods (can be triggered by failing dams and embankments, glacial lake outbursts, or by landslide-blocked rivers) and tsunami in coastal areas. For critical facilities such as major dams, power plants, or major hospitals, a more detailed analysis should be done to determine the expected level of earthquake shaking at that particular site. Hazard maps in the building codes provide sufficient information to properly design ordinary buildings and other typical structures. The building code or regulations for earthquake resistant design typically contain these maps, or they may be available from the government agency responsible for earth science or emergency management. Most countries that fall within earthquake hazard zones have maps that show how strong scientists expect earthquake shaking to be throughout the country. Scientists who study earthquakes use other tools: they investigate faults where earthquakes occur, measure the slow movement of tectonic plates, and search for geologic traces left by ancient earthquakes. In many areas, centuries may pass between major earthquakes, meaning that instrumental records provide an incomplete picture of the hazard. Recording of earthquakes using scientific instruments began only around 1900. Areas with infrequent, large earthquakes are sometimes classified as having medium seismic hazard.Ĭommunity memory and historical accounts of earthquakes can provide useful information to supplement scientific studies. But such earthquakes have happened in the past, and understanding the earthquake history of a place is important before determining a location for a project and initiating the design of the structures. It may seem unlikely that a large earthquake would take place hundreds of kilometers away from a tectonic plate boundary in areas with low levels of strain on the crust from tectonic motion. In many countries, earthquake history can be obtained from written historical records. Ministry of Environment and Geological Survey/ Ministry of Earth Sciences) responsible for earthquake risk management in the project country to obtain more detailed information on the potential earthquake hazard.Įven though the earthquake hazard is considered medium in your location, it is important to understand the earthquake history of the place to acknowledge the possibility that an earthquake can affect the region again. Community memory and historical accounts of earthquakes can provide useful information to supplement scientific studies.Ĭontact the governmental organisations (e.g. RecommendationsĮARTHQUAKE HISTORY AND HAZARD: Get information about major earthquakes and secondary hazards (fires, landslides, liquefaction, tsunami in coastal areas) that have affected the project area in the past and the effects these caused. Further detailed information should be obtained to adequately account for the level of hazard. Project planning decisions, project design, and construction methods should take into account the level of earthquake hazard. Based on this information, the impact of earthquake should be considered in all phases of the project, in particular during design and construction. This means that there is a 10% chance of potentially-damaging earthquake shaking in your project area in the next 50 years. In the area you have selected (Victoria) earthquake hazard is classified as medium according to the information that is currently available.
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