RICHTER SCALE Flashcards
(20 cards)
Who developed the Richter Magnitude Scale?
Charles F. Richter in the 1930s.
What does the Richter Scale measure?
The strength (amount of energy released) during an earthquake.
Why do seismologists now prefer the Moment Magnitude Scale (Mw) over the Richter Scale?
Because the Richter Scale (ML) has limitations for regional earthquakes greater than M5.
Is the Moment Magnitude Scale (Mw) similar to the Richter Scale?
Yes, both are logarithmic and give comparable numeric values.
How much more energy does a 6.0 magnitude earthquake release compared to a 5.0?
About 32 times more energy.
How much more energy does an 8.0 magnitude earthquake release compared to a 6.0?
About 1,000 times more energy (32×32).
What is the magnitude range for a microearthquake?
1.0 – 1.9, usually not felt by humans.
How many microearthquakes occur globally per year?
Several million per year.
What is the magnitude range for a minor earthquake?
2.0 – 2.9, felt slightly but causes no damage.
How many minor earthquakes occur annually?
Over one million per year.
What is the magnitude range for a light earthquake?
4.0 – 4.9, noticeable shaking but minimal damage.
How often do light earthquakes occur?
10,000 to 15,000 times per year.
What is the magnitude range for a moderate earthquake?
5.0 – 5.9, can cause damage to poorly constructed buildings.
How many moderate earthquakes occur yearly?
Around 1,000 to 1,500.
What is the magnitude range for a strong earthquake?
6.0 – 6.9, can cause moderate to severe damage.
What is an example of a strong earthquake?
The 2011 Christchurch earthquake (6.2 magnitude).
What is the magnitude range for a major earthquake?
7.0 – 7.9, causes damage to most buildings and can collapse weak structures.
Name two major earthquakes above 7.0 magnitude.
1819 Rann of Kutch earthquake (7.7-8.2) and 2001 Gujarat earthquake (7.7).
What is the magnitude range for a great earthquake?
8.0 – 8.9, causes destruction over large areas.
What was the most powerful earthquake ever recorded?
The 1960 Valdivia earthquake (9.4–9.6) in Chile.
