Earthquakes Based on The Depth of Focus Flashcards
(15 cards)
What are the three depth categories of earthquakes?
Shallow (0-70 km), Intermediate (70-300 km), and Deep (300-700 km).
What percentage of total earthquake energy comes from shallow earthquakes?
About 70-85% of the total energy released in earthquakes comes from shallow earthquakes.
What percentage of total earthquake energy comes from intermediate earthquakes?
About 12-15% of the total energy released in earthquakes comes from intermediate earthquakes.
What percentage of total earthquake energy comes from deep earthquakes?
About 3-5% of the total energy released in earthquakes comes from deep earthquakes.
How does the depth of an earthquake affect its destructive force?
A quake’s destructive force depends on its energy release, location, distance from the epicenter, and depth.
What are shallow-focus earthquakes?
Earthquakes with a depth of 0-70 km, mostly occurring in the Earth’s crust.
Why are shallow-focus earthquakes more destructive?
They release energy closer to the surface, causing greater damage in localized areas.
What are deep-focus earthquakes?
Earthquakes occurring at depths greater than 70 km, usually along subduction zones.
Where do deep-focus earthquakes commonly occur?
They occur in Wadati-Benioff zones, where one tectonic plate is subducting under another.
Why are deep-focus earthquakes generally less destructive?
Their energy dissipates over a wide area due to their great depth, reducing surface impact.
What is the strongest deep-focus earthquake ever recorded?
The magnitude 8.3 Okhotsk Sea earthquake in 2013 at a depth of 609 km.
What is the deepest earthquake ever recorded?
A magnitude 4.2 earthquake in Vanuatu at a depth of 735.8 km in 2004.
What is the Wadati-Benioff zone?
A zone of subduction where deep-focus earthquakes are common.
What was the depth of the 2016 Central Italy earthquake and why was it destructive?
It was a shallow earthquake at 10 km depth, making it more destructive.
How does the depth of an earthquake affect its felt intensity?
Shallower earthquakes are felt more strongly at the surface, whereas deep-focus earthquakes have less impact.
