Plate Tectonics: Hazards and Plate Boundaries Lecture 4, September ...
• Plate Tectonics: Hazards and Plate Boundaries Lecture 4, September 12, 2013 • •
active volcanoes are at/close to the tectonic plate boundaries Plate Boundaries and Hazards
-most active volcanoes are found on biggest plate border pacific plate.. most dangerous area is ring of fire
• •
The types of plate boundariesone
2 plates slide away in opposite direction
plate escape from 2nd plate-usually found in middle of the ocean 1st plate try to collied with 2nd plate…cause many problems such as earthquakes, volcanoes other natural disasters
convergent zone!! • •
Figure: Courtesy of USGS
• •
Divergent Boundaries: Oceanic ridges (spreading centres) (nail/year) The rate of spreading along the Mid-Atlantic Ridge is about 2.5 centimeters per year (cm/yr), or 25 km in a million years
ex. ireland -fisher eruption….different type of volcanic activity -marks deep plate boundary -in 8,000 years ??? american and eurasian plate moved -oceanic crust found in the middle…of 2 areas..where new ocean will be form in future -reason for active dangerous volcanoes in iceland
DIvergent Boundaries • •
Divergent Boundaries: Iceland. Figure: Courtesy of USGS
• •
Divergent Boundaries: Continental Rift Zones Spreading centers in the continents pull apart at much slower rates
easter africa is best example of divergent boundaries -triple junction…red african ridge where 3 plates meet -in future Somanlian is going to be island of its own. -oceanic divergent boundary is iceland -contiental divergent boundary is eastern africa
• •
Figure: Courtesy of USGS
•
Convergent Boundaries: Collision Zones (Continental Plate + Continental Plate) where huge mountains
location of different things is imp. for test!!!!
are formed!!! ex: india and asia..russia….leading to formation of Mt. Everest.
-more dense plate will subduct
• • • • •
Figure: Courtesy of USGS Convergent Boundaries: Subduction Zones (Oceanic Plate +Oceanic Plate) When two oceanic plates converge, one is usually subducted under the other, and in the process a trench is formed.
deepest place in the ocean are when 2 plates are meet in the ocean ex. mariana???? 10/11 km…trench -carribean and portorico???
hazard: under-ocean volcanoe… earthquake…tsunami (JAPAN..INDONESIA) • • • • •
Courtesy of the USG S Convergent Boundaries: Subduction Zones (Oceanic Plate + Continental Plate) A continental volcanic arc forms on a continent where oceanic lithosphere descends beneath the continental margin. Earthquakes are generated in this zone
oceanic plate goes down.. -on the shore…chain of volcanoes chain of volcanoes..in south america.. equador…peru… -chill gud example for earthquake -diff. type of natural hazards founds.
• • • • • • •
Courtesy of the US Geological Survey Transform Boundaries zone b/w 2 plates where they slide horizontally The zone between two plates sliding horizontally past one another is called a transform-fault boundary, or simply a transform boundary. The San Andreas fault zone (about 1,300 km long and in places tens of kilometers wide)slices through two thirds of the length of California. Along it, the Pacific Plate has been grinding horizontally past the North American Plate for 10 million years, at an average rate of about 5 cm/yr J. Tuzo Wilson, the Canadian geophysicist, discovered transform faults
#1 zone in the world…san andreas fault zone
pacific plate goes northwards
-ex. million years from now..maybe L.A and San francisco will be neighbours
-something fault in tokyo
• •
Courtesy of the US Geological Survey
The best env. for the earthquake…transform (BEST ANSWER!!! MOST DANGEROUS!!!) (EX. L.A GOT 1000/MONTH...(…sliding…)….divergent (can get it buh not dangerous…)…convergent…(deep somewhere in the ground…)
WHY WE HAVE IT WE DONT KNOW FOR SURE…SEVERAL HYPOTHESIS • • • • • • • • • •
Hotspot Hotspots – the surface expressions of hot columns of molten (or partially molten) rock anchored in the deep mantle. Origin of hotspots is unclear. At hotspots, plumes of hot but solid rock rising within mantle begin to melt as rock pressure on them drops. The volcanic Hawaiian Islands have formed in the middle of the Pacific Ocean Homework Chapter 2 (pp.17-18, 3rd ed. ) Chapter 2 (pp. 16 -17, 4th ed. )
YELLOWSTONE NATIONAL PARK…almost in the middle of the american plate…middle of the contient... -african mt. kamarun…HOT SPOT...
active volcanoes are at/close to the tectonic plate boundaries Plate Boundaries and Hazards
-most active volcanoes are found on biggest plate border pacific plate.. most dangerous area is ring of fire
• •
The types of plate boundariesone
2 plates slide away in opposite direction
plate escape from 2nd plate-usually found in middle of the ocean 1st plate try to collied with 2nd plate…cause many problems such as earthquakes, volcanoes other natural disasters
convergent zone!! • •
Figure: Courtesy of USGS
• •
Divergent Boundaries: Oceanic ridges (spreading centres) (nail/year) The rate of spreading along the Mid-Atlantic Ridge is about 2.5 centimeters per year (cm/yr), or 25 km in a million years
ex. ireland -fisher eruption….different type of volcanic activity -marks deep plate boundary -in 8,000 years ??? american and eurasian plate moved -oceanic crust found in the middle…of 2 areas..where new ocean will be form in future -reason for active dangerous volcanoes in iceland
DIvergent Boundaries • •
Divergent Boundaries: Iceland. Figure: Courtesy of USGS
• •
Divergent Boundaries: Continental Rift Zones Spreading centers in the continents pull apart at much slower rates
easter africa is best example of divergent boundaries -triple junction…red african ridge where 3 plates meet -in future Somanlian is going to be island of its own. -oceanic divergent boundary is iceland -contiental divergent boundary is eastern africa
• •
Figure: Courtesy of USGS
•
Convergent Boundaries: Collision Zones (Continental Plate + Continental Plate) where huge mountains
location of different things is imp. for test!!!!
are formed!!! ex: india and asia..russia….leading to formation of Mt. Everest.
-more dense plate will subduct
• • • • •
Figure: Courtesy of USGS Convergent Boundaries: Subduction Zones (Oceanic Plate +Oceanic Plate) When two oceanic plates converge, one is usually subducted under the other, and in the process a trench is formed.
deepest place in the ocean are when 2 plates are meet in the ocean ex. mariana???? 10/11 km…trench -carribean and portorico???
hazard: under-ocean volcanoe… earthquake…tsunami (JAPAN..INDONESIA) • • • • •
Courtesy of the USG S Convergent Boundaries: Subduction Zones (Oceanic Plate + Continental Plate) A continental volcanic arc forms on a continent where oceanic lithosphere descends beneath the continental margin. Earthquakes are generated in this zone
oceanic plate goes down.. -on the shore…chain of volcanoes chain of volcanoes..in south america.. equador…peru… -chill gud example for earthquake -diff. type of natural hazards founds.
• • • • • • •
Courtesy of the US Geological Survey Transform Boundaries zone b/w 2 plates where they slide horizontally The zone between two plates sliding horizontally past one another is called a transform-fault boundary, or simply a transform boundary. The San Andreas fault zone (about 1,300 km long and in places tens of kilometers wide)slices through two thirds of the length of California. Along it, the Pacific Plate has been grinding horizontally past the North American Plate for 10 million years, at an average rate of about 5 cm/yr J. Tuzo Wilson, the Canadian geophysicist, discovered transform faults
#1 zone in the world…san andreas fault zone
pacific plate goes northwards
-ex. million years from now..maybe L.A and San francisco will be neighbours
-something fault in tokyo
• •
Courtesy of the US Geological Survey
The best env. for the earthquake…transform (BEST ANSWER!!! MOST DANGEROUS!!!) (EX. L.A GOT 1000/MONTH...(…sliding…)….divergent (can get it buh not dangerous…)…convergent…(deep somewhere in the ground…)
WHY WE HAVE IT WE DONT KNOW FOR SURE…SEVERAL HYPOTHESIS • • • • • • • • • •
Hotspot Hotspots – the surface expressions of hot columns of molten (or partially molten) rock anchored in the deep mantle. Origin of hotspots is unclear. At hotspots, plumes of hot but solid rock rising within mantle begin to melt as rock pressure on them drops. The volcanic Hawaiian Islands have formed in the middle of the Pacific Ocean Homework Chapter 2 (pp.17-18, 3rd ed. ) Chapter 2 (pp. 16 -17, 4th ed. )
YELLOWSTONE NATIONAL PARK…almost in the middle of the american plate…middle of the contient... -african mt. kamarun…HOT SPOT...
