1. MT 5 LT 2

2.  What are the 3 types of plate boundaries?  What forms at a convergent boundary?  What is a subduction zone?

3.  Viscosity- is a substances ability to resist flow how runny the lava is. High viscosity is not runny and low is runny. Depends on the type of substances in it  Lava-magma that reaches earth’s surface melting rock

4.  What are the 3 factors that affect Viscosity of Magma/Lava? Temperature Silica Content Water Content High Viscosity Conditions Low Viscosity Conditions 1) TemperatureLowHigh 2) Silica ContentHighLow 3) Water ContentLowHigh

5.  What type of rocks meet the High & Low conditions? Low Viscosity:  Basalt is the type of rock on the bottom of the ocean & what ocean plates are made of  When it comes up as magma &turns into lava it is runny, viscosity is low. High Viscosity:  Silica-rocks that make up continental plates  magma rises and turns into lava by melting both basalt from ocean plate and silicates from the continental plate over the top.  Depending on the ratio of each, the lava has medium to high viscosity, explosive, etc.

8.  The sudden occurrence when large amounts of ash, gas and lava is released by a volcano Gases include: carbon dioxide and water vapor

9. Hot spots and Subduction Zones

10.  Not on a tectonic plates boundary  Caused by the upwelling of deep mantle plumes  This forms a chain of hot spot volcanoes as a tectonic plate passes over the mantle plumes  Dormant when not over mantle plume

12.  When one plate forced under another  The deep plate edge melts  Melted rock and gas works its way upward through the top plate  Always active due to the constant upwelling of magma

16.  SHAPE: Very gentle slopes  MADE FROM: Basalt ROCK  Formation: Formed out of layers of lava from repeated non-explosive eruptions  CONSISTENCY OF Lava: is mild and fluid; low viscosity  Over time, lava layers creating the gentle slopes.  LOCATION: CAN form in the middle of a plate over “hot spots” in the mantle  ERUPTION: non-violent because of low viscosity

19.  SHAPE: Tall & Steep sides with a broad base  MADE FROM: Continental & Oceanic rock – Silica with little basalt  LOCATION: Form at Subduction zones (convergent boundaries)  FORMATION: lava and ash pile up in alternate layers around the vent & form a cone-shaped mountain that comes to a point on top. (Examples: Mount Fuji in Japan, Mount Vesuvius in Italy.)  CONSISTENCY OF LAVA: high viscosity, high amount of silica  CHARACTERISTICS: Explosive eruptions of pyroclastic material followed by quieter outpourings of lava; Extremely dangerous; Erupt infrequently

21. Over the last 10,000 years, Mt. Shasta has erupted on average once every 800 years. During the 3,500 years the volcano has erupted about once every 300 years. The most recent eruption may have occurred in 1786 A.D.

23. Early sailors mistakenly thought glistening calcite crystals inside the tuff rocks were diamonds, leading to the incorrect name. Diamond Head formed when hot magma rising up a conduit hit ocean water, causing large explosions that threw exploded magma particles (tuff) into a broad ring. **Like ours here in Lindsay-Lindsay Peak

25.  Kohala is the oldest of the subaerial volcanoes that make up the Island Of Hawaii. Kohala is considered to be extinct because it has not erupted for 60,000 years.