Measuring and predicting tectonic hazards Flashcards
What are the negatives of measuring volcanic activity
it is still not possible to accurately predict when an eruption will occur or how long it will be
How can scientists measure to predict for volcanic eruptions
Its easier and more reliable to predict volcanoes compared to earthquakes because scientists can measure changes in gas emissions, ground deformation, hydrology, temperature changes and seismic activity
What are the negative of using the seismic gap theory
Although it presents a potential measurement of predicting earthquakes, there is still no definitive proven measure to predict earthquakes
What does a large seismic gap suggest
A seismic gap with no earthquakes can be interpreted as indicating an increased likelihood of a significant earthquake ( which can allow for evacuation of high risk areas)
Explain the Seismic gap theory
Seismic gap theory suggest that over a period of time all parts a fault must attain the same average level of movement, either through many minor or a few very large earthquakes.
What are the negatives of predicting tectonic events
Too many inaccurate predictions may increase the impact of future hazards as people begin to ignore warnings
What are the benefits of predicting tectonic events
An accurate prediction can reduce the impact of a hazard by allowing the evacuation of danger zones
How can predictability of tectonic hazards be measured
The relationship between tectonic hazards and plate boundaries allows the prediction of when an event will occur
What are the negatives of VEI as magnitude measurement for volcanoes
-Doesn’t take into account sulphur emissions, therefore no
account of effect on the atmosphere and climate change
- No account is taken of the different densities of erupted
materials
How is VEI measured
The volume of material erupted
The eruption cloud height
The direction of the eruption
How can magnitude by measured (Volcanoes)
What is the range on the scale
Volcanic Explosivity Index (VEI)
Scale ranges from 1-8
How can magnitude by measured (Earthquakes)
Richter scale
- based on amplitude of seismic waves measured with a
seismograph ranging from 1-9, but there is no upper limit
Moment Magnitude (MM) scale
- used since 2002 by United States Geological Survey (USGS)
for all modern, large earthquakes
- scale from 1-9
- Measures the energy released
Mercalli scale
- A qualitative scale that measures intensity based on the
effects on the Earth’s surface
- uses a scale from I to XII
