- What is the relationship between craters, calderas, vents, and magma? Craters are a depression at the top of the volcano. Craters lager than 1 km in diameter are known as calderas. The vent, where lava flows from, is also at the top of the volcano. But while the lava is inside the volcano, it is actually magma.
- How does a crater lake form? (words and pictures) It can happen when the side of the volcano collapses into the magma chamber that once fueled the volcano.
- What two factors does a volcano’s appearance depend upon? Material that it is made of and the type of eruption
- What characteristics vary among volcanoes? Size, shape, and composition
Type of Volcano
Materials & Description
- Shield Volcano
- Broad sloping sides and a nearly circular base. Forms when layers of basaltic lava accumulates
- Mauna Loa in Hawaii
- Cinder-Cone
- Steep sides and usually small. Forms when material ejected into the air falls back to Earth and piles up around the vent
- Izalco in El Salvador
- Composite (Stratovolcano)
- Medium sized, very explosive. Formed when layers of volcanic fragments alternate with lava.
- Mount St. Helens in Washington
- How do the volcanoes compare in terms of size and slope? Shield is the biggest and least steep, Cinder is the smallest and steepest, Composite is somewhere in the middle.
- What factors cause differences in size and slope? Materials that make up the volcano, vegetation around the volcano, climate, and eruption history.
- What is tephra? Rock fragments thrown into the air during a volcanic eruption
- What is a pyroclastic flow? Rapidly moving volcanic material
- Where are most volcanoes found? At plate boundaries, 80% being at convergent boundaries
- How do hotspots form? A hotspot is an unusually hot region of the Earth’s mantle where high-temperature plumes of mantle rise towards the surface. This happens when the intense heat from the mantle make plumes and the plumes melt rock and then it goes towards the crust as magma which then melts into the crust as volcanoes.
- What do hotspots tell us about tectonic plates? It can tell us how the plates are moving, in what direction, and how fast by the position of the volcano.
Volcanoes and Society Notes
75% of Earth's volcanoes are found in the Pacific ring of fire. The ring of fire stretches along east Asia, across Alaskan Islands, and along the coast of Americas. 600 million people living close enough to active volcanoes to be affected when they erupt. 300,000 have died in the past 200 years from volcanoes, but socioeconomic and disruption is considerable.
Risks?
Flooding- due to rise in water level/ glacier melting ...that destroys property
Global Climate Impact- Sulfur clouds make Earth's atmosphere more reflective, cooling the planet. Interferes with crop production.
Lots of Property Damage is massive because insurance isn't typically available.
How do we analyze disaster risk?
Disasters occur daily. Sometimes the effects are felt just locally and at other times is is felt nationally
Globally, the number of natural disasters has increased 4x in the past three decades.These can exert an uneven impact on third world countries because they don't have much capital.
To calculate risk, we have to have information about past events. This helps us estimate return periods and better prepare and manage future events. Disaster risk can be calculated by dividing the number of past events by the time period over which they occurred .
75% of Earth's volcanoes are found in the Pacific ring of fire. The ring of fire stretches along east Asia, across Alaskan Islands, and along the coast of Americas. 600 million people living close enough to active volcanoes to be affected when they erupt. 300,000 have died in the past 200 years from volcanoes, but socioeconomic and disruption is considerable.
Risks?
Flooding- due to rise in water level/ glacier melting ...that destroys property
Global Climate Impact- Sulfur clouds make Earth's atmosphere more reflective, cooling the planet. Interferes with crop production.
Lots of Property Damage is massive because insurance isn't typically available.
How do we analyze disaster risk?
Disasters occur daily. Sometimes the effects are felt just locally and at other times is is felt nationally
Globally, the number of natural disasters has increased 4x in the past three decades.These can exert an uneven impact on third world countries because they don't have much capital.
To calculate risk, we have to have information about past events. This helps us estimate return periods and better prepare and manage future events. Disaster risk can be calculated by dividing the number of past events by the time period over which they occurred .
Earthquake Guided Notes
Stress- forces per unit area acting on a material
Strain- deformation of materials in response to stress Reverse Fault- fractures that form as a result of horizontal compression Normal Fault- Fractures caused by horizontal tension Strike-Slip Fault- Fractures caused by horizontal shear Primary Waves- squeezes and pulls rocks, goes left and right Secondary Waves- rocks move in right angles, goes up and down Surface Wave- moves in two directions as it goes through the rocks The focus and the epicenter are both the center of the storm, but focus is below the ground and epicenter is above ground The greater the distance between "P" and "S" waves on a seismograph the longer the distance away from the epicenter Ritcher scale is used to measure energy released during an earthquake. The range is from 1-10, each on 10x bigger than the next Modified Mercalli Scale is used to measure the intensity during an earthquake and it uses Roman numerals I- XII Earthquake Level 1- Not felt except under special circumstances Level 5- Felt by everyone, breaks some glass Level 10- Most ordinary structures are destroyed, Landslides are common 5 Safety Tips for Surviving an Earthquake
1. Make a family safety plan stating where you would meet in case of an Earthquake 2. Do NOT go outside in the middle of an Earthquake, no matter what 3. Get on your hands and knees and cover your head and neck 4. Stay away from glass or anything that can break and harm you 5. After the Earthquake is over, still be careful for aftershock |
5 Safety Tips for Surviving a Tsunami
1. Tsunamis are more than one wave, stay out of harm's way until officials give the "All clear"
2. NEVER go down to the beach to see a tsunami, tsunamis move faster than anything
3. Upper levels of buildings are good places to stay if you can not leave the coast
4. If there is any shaking, get on your hands and knees and cover your head and neck
5. Stay informed on the conditions of the sea and any near-by Earthquakes because Earthquakes often lead to Tsunamis.
1. Tsunamis are more than one wave, stay out of harm's way until officials give the "All clear"
2. NEVER go down to the beach to see a tsunami, tsunamis move faster than anything
3. Upper levels of buildings are good places to stay if you can not leave the coast
4. If there is any shaking, get on your hands and knees and cover your head and neck
5. Stay informed on the conditions of the sea and any near-by Earthquakes because Earthquakes often lead to Tsunamis.