Lithosphere KQ 2 What natural hazards are derived from plate movement and how are they managed?

Volcano Basics Opening in Earth’s crust from which comes molten rock, gases, and ash The name of the landform around such an opening http://video.nationalgeographic.com/video/101-videos/volcanoes-101?source=searchvideo

Why they form Decrease in pressure (in asthenosphere due to the lithosphere) (rift zone) Increase in temperature (hot spot) Increase in water (decreases melting point) (subduction zone)

Where they form Rift zone (mid ocean ridge, divergent boundary) Subduction zones (convergent boundaries O-O, O-C) Hot spots (ocean (hawaii), land (yellowstone))

Volcano/Magma Characteristics Based on Amount of Silica Basaltic- low silica, gas & viscosity, high temp& flow @ rifts and ocean hot spots Andesitic-mod. Gas & viscosity, inter. Temps, sometimes explosive @subduction boundaries Rhyolitic-high silica, gas, viscosity, explosive, low temps @ continental hot spots

Based on magma/lava flow Volcanic landforms Based on magma/lava flow Shield - large gently sloping (basaltic magma-Hawaii) Cinder cone – small from vents near larger volcanoes Composite – explosive volcanic eruption layers (magma, water, ash, mud flows) Mt. St. Helens Caldera – top blows, crater-collapses (Yellowstone Crater lake)

Mauna Kea Last eruption 4,500 ya Landform shield, Characteristic basaltic Last eruption 4,500 ya

Iceland April 14, 2010

Mt. Fuji Last eruption 1707, overdue for another Landform Composite, Characteristic Last eruption 1707, overdue for another

St. Helens 1980 type composite, characteristic : Last eruption 1980

Amboy California Last eruption ~6,000 ya Type cinder, characteristic basalt andesite Last eruption ~6,000 ya

Crater Lake Oregon Last eruption 7,700 ya Type Caldera lake is 594 meters deep (1,949 ft) Last eruption 7,700 ya

Monitoring Tools Tiltmeters – expansion/dome of area (balloon buried under layers of sand/plaster) Geodimeter – change in horizontal distance via laser Earthquake frequency – peaks before eruption Gas emission - via correlation spectrometer “sees sulfur dioxide” Historical eruptions – written and geologic

Just for fun…Extraterrestrial Vulcanism Moon (maria) 15 % basaltic lava flows 3-4 BYA Mars several shield volcanoes Venus 1600 large volcanoes, lava flows, and calderas Io (moon of Jupiter) caused by friction of surface pulled by gravity of Jupiter and other nearby moons.

Volcano Activities Volcano Vocabulary worksheet Hawaii lab Google Earth exercise http://www.volcano.si.edu/world/globallists.cfm?listpage=googleearth

Earthquake Basics - Cause http://video.nationalgeographic.com/video/101-videos/earthquake-101 Strain (in lithosphere) Faults (Cracks) Plate boundaries Release (of energy) Volcanic eruption Cave collapse Bomb detonation Meteor impact

Earthquake Cycle

Cross Section of an Earthquake Focus-where the rupture/break occurs. Epicenter-directly above the focus on the Earth’s surface. Seismic waves radiate out in all directions (remember the bull’s eye).

Where do Earthquakes occur and what can they tell us about plate boundaries? ArcGIS Earthquake lesson

Movement/Magnitude of an Earthquake depends on: The shape of the boundary The depth of the stress release The type of rock Review ArcGIS lesson

Boundary shape = Fault type We know that the continental plates are moving and can collide (continental drift). > < Compression/subduction/mountain building. < > Extension/rift zone/sea floor spreading. Sliding/San Andres Fault. But what else can continental drift cause…

Review Earthquake Cycle Static deformation accounts for about 90% of the energy from an earthquake. Where is the other 10%? Seismic waves. 90% of energy from earthquake results in static deformation (change shape). What accounts for the other 10% of energy?

Seismic Waves Body waves Surface waves P-waves S-waves Love waves Raleigh waves (view CZ ES1002)

Seismic Waves There are two main types of seismic waves BODY (travel through the Earth’s inner layers) and SURFACE (move only along the Earth’s surface). Today’s focus is on body waves. There are two types P-waves (travel through rock and fluid, like thunder rattles windows, sound pushes and pulls the air). Demonstration on overhead with shallow glass pan filled with water. Drop a pebble in watch the waves propagate outward. S-waves move only through rock both up and down and side to side. Demonstration with rope tied to doorknob, up and down waves and side to side waves. Pull up website with animation of slide. There are other types of seismic waves that occur only on the surface but we won’t discuss them Pull up website with animation http://www.kettering.edu/~drussell/Demos/waves/wavemotion.html

Observation/Recording seismograph A seismograph is the instrument used to measure earthquakes. What else do they record? (Explosions, nuclear tests). Recorders at different locations are used to pinpoint the location of an earthquake. Different distances from the point of rupture result in different times. Because the speed of the waves is relatively constant at 8 km/s.

Interpret a Travel-Time Graph (P-S graph)

World Earthquake Map For this slide I used a push pin to poke a hole in the pie-crust, because each dot represents a rupture in the Earth’s surface and earthquake. What the lines of wholes outline? (the continental plates) Then manipulate the dough pushing in one direction cause a pull in another-shows subduction where they collide, and rift zone where they pull apart. **See the continental plates?

Misawa This next slide shows what? The “Ring of Fire” - discuss.

Secondary Hazards Tsunami - http://video.nationalgeographic.com/video/101-videos/tsunami-101?source=searchvideo Landslide - http://video.nationalgeographic.com/video/101-videos/landslides?source=searchvideo Pyroclastic flow (Nuee Ardentes) - http://www.discovery.com/tv-shows/discovery-presents/videos/ultimate-guide-to-volcanoes-pyroclastic-flow/