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Displaying 135 of about 339 resultsTsunami is a Japanese term meaning wave (‘nami’) in a harbour (‘tsu’). It is a series of travelling waves of extremely long length and period. They are usually generated by seabed disturbances associated with earthquakes occurring below or near the ocean floor, but also by other mechanisms such as submarine landslides (IOC, 2019).
Landscape creep is the imperceptibly slow, steady, downward movement of slope-forming soil or rock. Movement is caused by shear stress, sufficient to produce permanent deformation, but too small to produce shear failure (adapted from Hutchinson, 1968; and Varnes, 1978).
Riverbank erosion is the removal of material from the banks of rivers when flowing water forces exceed bank resisting forces by the soil and vegetation, for example, when river levels are sufficiently high, primarily due to fluvial energy and atmospheric processes and secondarily because of the resultant geotechnical instability and consequential riverb…
Subsidence is a lowering or collapse of the ground (BGS, 2020). Uplift is the converse.
Ground fissures form in response to tensional stresses, most commonly in unconsolidated sediment, but also in rock (Arizona Geological Survey, 2020).
Ground shaking is the movement of the Earth’s surface from earthquakes. Ground shaking is produced by waves that travel through the earth and along its surface (USGS, no date).A volcanic earthquake is any earthquake that results from tectonic forces which occur in conjunction with volcanic activity (UN-SPIDER, no date).
A lava flow or lava dome is a body of lava that forms during an eruption, or main eruptive episode. Lava flows are outpourings of fluid, relatively low-viscosity molten rock, whereas a lava dome is a pile of relatively viscous lava that cannot flow far from the vent (Calder et al., 2015; Kilburn, 2015).
Tectonic uplift and subsidence are the distributed vertical permanent ground deformations (warping) that result from earthquake displacements on a dipping (inclined) fault (Styron, 2019). This includes changes to the shoreline as a result of uplift and subsidence.
Earthquake is a term used to describe both sudden slip on a fault, and the resulting ground shaking and radiated seismic energy caused by the slip, or by volcanic or magmatic activity, or other sudden stress changes in the Earth (USGS, no date).
Radio blackout is a prolonged period of fading or faded radio communications, primarily in the high frequency range from ionospheric changes because of increased solar activity, in particular solar flares of C-class level or higher on the sunlit side of Earth (AMS, 2018).
An ionospheric storm is defined as turbulence in the F region of the ionosphere, usually due to a sudden burst of radiation from the Sun (WMO, 1992).NB. The F region is the highest region of the ionosphere, at altitudes greater than 160 km (100 miles).
A meteorite is an object that survives a trip through Earth’s atmosphere and hits the ground (adapted from NASA, no date).
Deforestation is the conversion of forest to other land use independently of whether human-induced or not (FAO, 2020).
Soil erosion is defined as the accelerated removal of topsoil from the land surface through water, wind and tillage (FAO, 2020).
Nonpoint sources of pollution refer to pollution sources that are diffused and without a single point of origin or not introduced into a receiving freshwater or maritime environment from a specific outlet. The pollutants are generally carried off the land by storm-water run-off. The commonly used categories for nonpoint sources are agriculture, forestry…