Hazards Flashcards
Geophysical
A geophysical hazard is potentially damaging natural event encompassing geologic or geomorphological activity, which may cause the loss of life, injury, property damage, social and economic disruption, or environmental degradation. An example is a seismic event such as earthquakes.
Atmospheric
An atmospheric hazard is a potentially damaging natural event that is caused due to an atmospheric process. Examples could be wildfires or tropical storms (shared between atmospheric and hydrological as both events need to be present.)
Hydrological
A hydrological hazard is a potentially damaging natural event which is caused due to an abnormality of process within water- be it lakes, rivers, oceans etc. Examples include tropical storms (shared between hydrological and atmospheric as both events need to be present.)
Fatalism
An attitude or viewpoint that people can’t shape the outcome of a hazard. Represents an ‘acceptance’ of the probability of being involved in a natural disaster and risk involved as such but no further actions are viewed as necessary. Nothing can be done to mitigate against the risk- little or no preventative measures are put in place ‘gods will’
Adjustment/adaptation
Responding to or altering one’s designs or protocols to help reduce the impact of a natural hazard.
Mitigation
A perception that hazards can be measured and are predictable. Through engineered soloutions and or technology they can be controlled and effects reduced.
Crustal evolution
The natural geological processes of fomation, destruction and renewal of the outer shell of Earth’s surface through plate tectonic movement and resulting effects such as seafloor spreading.
Gravatitional sliding/ridge push
A proposed driving force for plate motion in plate tectonics that occurs at mid-ocean ridges as the result of the rigid lithosphere sliding down the hot, raised asthenosphere below mid-ocean ridges.
Slab pull
The pulling force exerted by a cold, dense oceanic plate plunging into the mantle due to its own weight. The theory is that because the oceanic plate is denser than the hotter mantle beneath it, this contrast in density causes the plate to sink into the mantle.
Convection currents
-Theory where very hot material at the deepest part of the mantle rises, cools, and sinks before being heated again. repeating the cycle over and over. this spreads at its farthest point from Earth’s core, pushing the above plates with it, leading to tectonic plate movement.
Seafloor spreading
A process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge, can be observed through paleomagnetism.
Continental drift
A theory that explained how continents shift position on Earth’s surface, set in 1912 by Alfred Wegener, a geophysicist and meteorologist, continental drift also explained why look-alike animal and plant fossils and similar rock formations are found on different continents.
Seismicity
A study in geophysics and measure encompassing earthquake occurrence, mechanisms and magnitude at a given location.
Vulcancity
The process through which gases and molten rock are either extruded on the earth’s surface or intruded into the earth’s crust.
Magma plumes
In areas of hot, upwelling mantle, a hot spot develops above the plume in the crust. Magma generated by the hot spot rises through the rigid plates of the lithosphere and produces active low-viscosity volcanoes at the Earth’s surface. These can lead to deep sea trenches or island arcs.
Lava flows
A moving outpouring of lava, created during a non-explosive effusive eruption. When it has stopped moving lava solidifies to form igneous rock.
Lahars
A flow of wet material down the side of a volcano consisting of erupted ash and water. Found when heavy rainfall occurs after a volcanic eruption- essentially they are volcanic mudflows
Pyroclastic flow
A fast-moving current of hot gas and volcanic matter (collectively known as tephra) that moves away from a volcano at 100km/h on average reaching up to 700 km/h
Gases/acid rain
Volcanoes exhaust dangerous gases such as sulphur dioxide reacts with water molecules, acidifying them and producing acid rain when dropped.
Tephra
Fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclastic flows.
Spatial distribution
In this case, of a natural event, represents the geographical spread of results or data
Magnitude
The size of a hazard- how powerful or damaging it is
Frequency
Represent how often or the assumed likelihood of an event occurring
Shockwaves
When an earthquake occurs, it produces seismic shockwaves, two types can travel through earth’s interior- P (primary) or S (secondary), they both move in different ways, outwards from the hypocentre (focus).
