Semiar Prep - Tectonics Flashcards
The Nazca plate moves 79mm a year towards what plate?
The South American
What continent did I study?
South America
What happens when the Nazca ate and South American plate meet?
Dense oceanic lithosphere of Nazca forced under buoyant South American
How does the are descend into the mantle? And what’s it’s scientific name?
At an angle
Scientific name - subduction
What is at the surface of this ocean?
The Peru-Chile trench
What does the friction between the two plates stop?
The oceanic sliding smoothly
When the Nazca plate descends it drags on the overlying plate, what does this cause? Also what does it result in?
Fracture and deform
Results in shallow focus earthquakes known as Benioff zone
As subduction continues, some sediments in ocean floor are scraped off and forced onto South American plate, what is this process?
Obduction
What does obduction do?
Forms a wedge where sediments thrust on South American plates adding to size of continent
What are the 3 effects of the collision between the Nazca plate and South American?
- Increases vertical thickness
- Reduces width of lithosphere
- Produces fold of the Andes
What was the shallowest and deepest earthquakes during the week commencing 13 October?
Shallowest - 10km, Nazca Plate by Chile
Deepest - 128.5km by Chile, however away from the Nazca plate further inland
What does it suggest the further inland you go from my own research, also what was one exception?
Further inland the quakes are deeper
One exception on 5th October 16.5km one in Peru
What was the smallest and largest quake in the last week from my own research?
Smallest - 4.3M by Columbia
Largest - 5.8M by Chile
A historic earthquake in this area was what magnitude, and where?
8.4M
Coast of Peru Earthquake
What was the date of the Coast of Peru earthquake?
2001 June 23 - 20:33
How many people were killed by earthquake, killed by Tsunami in the coast of Peru quake?
Quake - 75
Tsunami - 26
How many people were injured in Coast of Peru quake?
2687
How many homes were destroyed, how many were damaged in C.o.p?
17,510 home destroyed
33,548 damaged
What did landslides do in coast of Peru quake?
Blocked highways near epicentral centre
Where else was Coast of Peru quake felt?
Southern Peru and Northern Chile
What did Coast of Peru quake do?
Cause a Tsunami?
How large was waves of Tsunami in Coast of Peru? Also how far did it reach inland?
7m high in some areas
Inland - 1km
How did coast of Peru quake occur?
Thrust faulting on interface between two plates, with SA moving up and seaward over Nazca
The coast of Peru had a history of earthquakes name 2 others?
- 7M in 1996
9. 0M in 1868 - tsunami killed thousands
Where did the Tsunami strike?
Peruvian Coast
Where was the damage minutes to from the Tsunami?
South Central portion, from Atico (North) to Matarani (South)
Where was hit worst from Tsunami, what was wave heights and how far inland?
Camana
7m high. 1km inland
La Punta a popular resort area suffered what?
Loss of 100homes, hotels, restaurants
Luckily why was there not many more injuries/deaths from tsunami?
It was winter so destination resorts deserted
How many surges from the tsunami was there?
3-5
How many structures damaged and how many hectares of farmland flooded?
3k structures damaged
2k hectares flooded, tourism agriculture suffered
It happened midday what did people notice?
The drawback so had time to react
