Potential Earthquake Hazards-PDF

## Chapter 2: Understanding and Potential Earthquake Hazards ### Lesson 4: Potential Earthquake Hazards - **Earthquake** - It is also referred to as a force called **stock**. - Generates weak to strong shaking on Earth's surface due to the movement of rock material underneath. - The pr...

## Chapter 2: Understanding and Potential Earthquake Hazards ### Lesson 4: Potential Earthquake Hazards - **Earthquake** - It is also referred to as a force called **stock**. - Generates weak to strong shaking on Earth's surface due to the movement of rock material underneath. - The primary source of force from underneath is called the **hypocenter**. - **Focus** is present parallel to the locus at the surface hypocenter. - **Epicenter** is directly above the source of force. - While most earthquakes come from the movements of tectonic plates, volcanic activity and manmade disturbances may also cause earthquakes. - Simple movements of land can occur either at the plate level or the fault line level, creating a variety of effects on land. - **Types of Faults** that may occur depending on the area's location as well as composition: - **Left Lateral Strike-Slip Fault:** The displacement of the fault block is to the left when viewed from either side. - **Right Lateral Strike-Slip Fault:** The displacement of the fault block is to the right when viewed from either side. - Each type presents a unique, dynamic, unifying factor in that slippage creates a wave of energy. Once pressure can no longer be sustained, the process is no longer sustainable. ### Earthquake hazards: 1. **Ground shaking (or Ground motion):** When the Earth shakes with the passage of an earthquake (seismic wave), which radiates energy that had been stored in stressed rocks. 2. **Ground rupture (break):** In an offset of the ground surface when a fault rupture extends to the Earth's surface. 3. **Liquefaction:** A phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading, normally occurring in saturated soils 4. **Catastrophic induced ground subsidence and lateral spreading:** - **Subsidence:** Is the sinking of the ground surface often occurring during earthquakes. - **Lateral spreading:** Is the finite, lateral movement of gently to steeply sloping saturated soil deposits caused by earthquake-induced liquefaction. 5. **Tsunami (a.k.a. seismic seawave):** A series of waves in a water body caused by the displacement of a large volume of water, generally in the ocean or large lakes. 6. **Earthquake-induced landslides:** Landslides are frequently triggered by strong ground motions. Individuals vary with the range of ground movement, such as rock falls.