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Flashcards in 1.5A - Tokohu Deck (15):

Scales that measure hazards based on intensity

Mercalli Scale
(Tsunami Intensity)


Scales that measure hazards based on magnitude

Moment Magnitude Scale
Volcanic Explosivity Index
(Richter Scale)


What does Logarithmic mean?

A scale that increases proportionally to the event
EG - A volcanic eruption of 4 is 10x smaller than one of 5 on the VEI


What is used to calculate the VEI of an eruption?
(3 things)

Volume of product released
Height of the eruption cloud
Qualitative observations


Which scale in more accurate in measuring earthquake magnitude, the Richter Scale or the Moment Magnitude Scale? Why?

The Moment Magnitude Scale - it measures the energy released by all shockwaves, not just P and L waves, as well as the area of the rupture and movement


Why is the Mercalli Scale described as a relative scale?

It measures the experienced impacts of an earthquake, meaning it is fairly subjective


What affects the impact of a hazard event?

The event itself - size, duration
The environment it happened in


Why is the Richter Scale defined as an absolute scale?

All earthquake events are measured using the same parameters, meaning if 2 earthquakes that were the same happened in 2 different locations, they would be the same


What are some of the key responses used in the Mercalli Scale?

The number of people who were woken by the event
The movement of furniture
The damage to structures


What is used to calculate the Moment Magnitude Scale?

The energy released - things like the amount of slip in the fault, or the total area affected are also used


Define intensity

The amount of damage created by a tectonic event or other hazard


Define magnitude

The amount of energy released by a tectonic event


What percent did GDP drop by following the earthquake?



What magnitude was the earthquake?

9.1mW - 4th largest in the world


How long was it before the Shinkansen Bullet Train was back in service?

1 day