Earthquake Hazard level: Very low ?

In the area you have selected (Montserrado) earthquake hazard is classified as very low according to the information that is currently available. This means that there is less than a 2% chance of potentially-damaging earthquake shaking in your project area in the next 50 years. Based on this information, the impact of earthquake need not be considered in different phases of the project, in particular during design and construction. Although the hazard is considered to be very low or non-existent in the project location based on the information available in ThinkHazard!, additional information may show some level of hazard. If local or additional information sources suggest that there is earthquake hazard, follow the recommendations below and seek expert guidance on additional recommended actions.

Recommendations

• EARTHQUAKE HISTORY AND HAZARD: Get information about any earthquakes and secondary hazards (fires, landslides, tsunami in coastal areas) that have affected the project area in the past and the effects these caused. Community memory and historical accounts of any past earthquakes can provide useful information to supplement scientific studies. Contact the governmental organisations (e.g. 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 any potential earthquake hazard. More information
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  Even though the earthquake hazard is considered very low 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. In many countries, earthquake history can be obtained from written historical records. 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. 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. Scientific knowledge is incomplete, and earthquakes have occurred in places thought to have very low hazard.

  Community memory and historical accounts of earthquakes can provide useful information to supplement scientific studies. Recording of earthquakes using scientific instruments began only around 1900. In many areas, centuries may pass between major earthquakes, meaning that instrumental records provide an incomplete picture of the hazard. 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.

  Most countries that fall within earthquake hazard zones have maps that show how strong scientists expect earthquake shaking to be throughout the country. 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. Hazard maps in the building codes provide sufficient information to properly design ordinary buildings and other typical structures. 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. Engineers need this additional information to design the facility properly.

  Earthquakes can cause secondary hazards that include fires, landslides, floods (can be triggered by failing dams and embankments, glacial lake outbursts, or by landslide-blocked rivers) and tsunami in coastal areas. Obtain information on these hazards from the government agency responsible for emergency management. Maps may exist that describe the extent of tsunami inundation, liquefaction, or land-sliding. Historical records may also contain accounts of secondary hazard events triggered by past earthquakes. Learning about potential tsunami hazard is essential in coastal areas with high, medium, or low earthquake risk.

  Earthquakes triggered or induced by human activity are not included in these hazard levels. Instances of 'induced seismicity' and its causes are recorded at http://inducedearthquakes.org/ .

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• LOCAL BUILDING REGULATIONS: Find out if the local building regulations include minimum standards for earthquake protection, even in very low hazard areas. To do this, engage the local engineering community, especially those serving with the local government, in discussions; or consult external experts. Comply with the minimum standards. More information
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  Building standards, often called building codes, provide the first line of defense against potential earthquake damage and help to ensure safety in buildings designed and constructed in conformance with the codes. It is important to find out if the local building regulations provide for a minimum level of earthquake protection in the project location. If they do, then comply with the regulating provisions with respect to planning, design and construction, including typology of construction and quality materials for use in areas of seismic hazard.

  More Information: The Importance of Building Codes in Earthquake-Prone Communities : http://www.fema.gov/media-library-data/1410554614185-e0da148255b25cd17a5510a80b0d9f48/Building%20Code%20Fact%20Sheet%20Revised%20August%202014.pdf

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