It is a smaller earthquake tremor that occurs after a large earthquake, in the same area of the main shock. It results from the sudden change in stress occurring within and between rocks and the previous release of stress brought on by the principal earthquake. Aftershocks occur in rocks located near the epicentre or along the fault that harboured the principal earthquake.
They are instruments used to detect and record earthquakes. It is used for measuring the direction, intensity, and duration of earthquakes by measuring the actual movement of the ground.
It is the practice of exploiting a natural disaster, a miserable condition or emergency situation for one's selfish advantage. This term was used to describe the US Government’s reaction over Hurricane Katrina.
It refers to a movement of individuals or groups who are actively preparing for emergencies including possible disruptions in social or political order, on scales from local to international. These individuals/groups are called survivalists or preppers.
The Richter magnitude scale is used to measure the amount of energy released by an earthquake. Also known as Richter scale, it is used by seismologist to express seismic energy. Nowadays, moment magnitude scale is preferred because it works over a wider range of earthquake sizes and is applicable globally.
Stress accumulation that may occur between two locked plates can result in potentially destructive types of earthquake. It occurs at subduction zones at destructive plate boundaries, where one tectonic plate is subducted by another. Since 1900, all earthquakes of magnitude 9.0 or greater have been mega thrust earthquakes.
It is an event where a local area experiences sequences of many earthquakes striking in a relatively shorter period of time. Earthquake swarms are typically witnessed before volcanic eruptions.
Soil Liquefaction refers to the phenomenon whereby soil loses strength and stiffness in response to an applied stress, usually earthquake, shaking or other sudden change in stress conditions. This prompts the soil to behave like liquid. The strength of the soil decreases and, the ability of a soil deposit to support foundations for buildings and bridges is reduced.