Boundaries
What do you call the boundary where two plates slide past each other in opposite directions?
Provide a famous example
Transform Boundary
San Andreas Fault
What is an earthquake and where do most earthquakes happen?
An earthquake is the release of the energy built up between two plates as they try to move past each other in opposite directions, they are found at transform and convergent boundaries and are most commonly found in an area called the Ring of Fire
What is a volcano and where are they commonly found.
A volcano is a mountain that forms in Earth’s crust when molten material, or magma reaches the surface, they are commonly found at hotspots and along plate boundaries most commonly around the Pacific Plate in an area known as the Ring of Fire.
Mount Vesuvius had this type of major explosive eruption in what year?
A Vesuvian or Plinian eruption in the year 79AD (CE)
Explain the Theory of Plate Tectonics; what other theories is it based off of, describe them, who came up with those theories, what evidence supports them.
The Theory of Plate Tectonics states that the plates of the Earth's crust are in constant motion at varying speeds and suggests that all of the land masses on Earth were once a supercontinent 225 million years ago called Pangaea and that based on current movement they will one day come together again to form a new supercontinent.
It is a combination of Wegner's Theory of Continental Drift and Hess's Theory of Sea Floor Spreading.
Evidence to support the theory: Fossils, glacial deposits, matching stratigraphy, and the constant construction and destruction of the Earth's crust at the Mid- Atlantic Ridge and the Mariana Trench respectively.
Describe the Mid-Atlantic Ridge
A divergent boundary where 2 plates are moving away from each other, increasing the size of the Atlantic Ocean by about 2-3 cm per year, newer rock is found closest to the ridge
Describe what a tsunami is and how it is formed.
Tsunamis are giant waves that can be hundreds of feet high and move at speeds up to 500 miles an hour, they are created from the transfer of energy from an underwater earthquake into the ocean.
Name and describe the main parts of a volcano.
Magma chamber - a pocket of magma that collects beneath a volcano
Pipe - a long tube that extends from Earth’s crust up through the top of the volcano
Vent - an opening in a volcano through which molten rock and gases leave a volcano
Central/Main Vent - single vent at the top of the volcano
Side Vent - additional vents along the sides of a volcano
Lava Flow - the spread of lava as it pours out of a vent
Crater - a bowl-shaped area that may form at the top of a volcano, near its central vent
How often to Plinian eruptions occur and when is Mount Vesuvius due for its next Plinian eruption?
Plinian eruptions occur approximately once every 2,000 years and Mount Vesuvius is due for a Plinian eruption in the next 100 years (this could happen tomorrow or in a century)
List and describe the layers of the Earth.
Crust - the outer most and thinnest layer on which we stand, solid
Asthenosphere - the softer section of the top of the Mantle which allows the plates to move
Mantle - largest section, solid
Outer Core - liquid layer of molten iron and nickel
Inner Layer - solid layer of extremely hot iron and nickel under high pressure from gravity
Explain how the Himalayan Mountain Range formed
The Himalayan Mountain Range was formed when two continental plates (the Indian Plate and the Eurasian Plate) converged
Who studies earthquakes and what instruments do they use?
Scientists who study earthquakes are called seismologists and they use seismographs to record seismic waves released by an earthquake to determine the earthquake's epicenter and they measure the magnitude of an earthquake using the Richter Scale
What are the three main types of volcanoes and how do geologists classify them?
The three main types are:
1) Cinder Cone Volcanoes
2) Composite or Stratovolcanoes
3) Shield Volcanoes
Classified based on four things:
height, shape, magma type, and eruption style
Describe a pumice stone.
Pumice stones are formed when gaseous rock and ash are thrown high enough into the atmosphere to cool instantaneously into solid rock trapping air inside of them in the process, allowing them to float in water due to their lower density.
Explain what a hotspot is, how it works and provide the two famous examples in the United States of America.
A hotspot is an area where material from deep within Earth’s mantle rises to the crust and melts to form magma above which a volcano forms
Hotspots stay in one place while plates move over them
Famous examples include Hawaii and Yellowstone National Park
Explain how the Rockies were formed
The Rockies were formed when the oceanic Pacific Plate submerged at a shallow angle beneath the continental North American plate causing the submerged Pacific Plate plate to scrape along the bottom of the North American plate and forcing up pieces of the continental crust to form block mountains
Describe the Richter Scale, what is it used for and what do its numbers mean?
The Richter Scale is used to ascribe a single number to identify the magnitude of an earthquake, earthquakes measuring under a 5 cause little damage, earthquakes over 6 cause serious damage, and earthquakes over 8 are very rare, but cause the most damage.
Describe a shield volcano.
large, broad, gentle slope, resembles a warrior's shield, has low silica content and low viscosity and has quiet eruptions
What happened to the cities and people of Herculaneum and Pompeii due to the eruption of Mount Vesuvius in 79AD (CE)?
Herculaneum and Pompeii were both buried for thousands of years under layers of solidified ash after Mount Vesuvius erupted in an extremely explosive eruption called a Plinian eruption. The ash entombed the city of Pompeii leaving it basically frozen in time and leaving behind empty spaces were the people had died, which were turned into plaster casts.
Some people fled the cities, but many did not.
The people who stayed in Herculaneum were either in the boathouses where they died from thermal shock and left behind skeletal remains of their shattered bones, those who had not reached the boathouse died instantaneously, turning into charcoal when a Pyroclastic Flow hit the city.
People who stayed in Pompeii also faced death, but they were either trapped inside houses with collapsing roofs, were exposed to toxic volcanic gases that prevented them from breathing and burnt their eyes, nose, and throat and eventually were all exposed to the residual effects of a pyroclastic surge that stopped just short of the city walls, but provided enough heat to cause the people to burn their lungs turning their last breaths into a cement like mixture of molten ash and fluids from their lungs.
Name and explain the 3 stages of a volcano's life and provide an example of each.
Active - has erupted at least once in the last 10,000 years (within historical times)
Dormant - has not erupted in the last 10,000 years, but is expected to erupt again (Mount Kilimanjaro)
Extinct - has not erupted in the last 10,000 years and is expected to never erupt again (Kohala)
Explain how the Islands of Japan were formed
Japan is an island arc which is found above a trench formed at the convergence of two oceanic plates
List and briefly describe the three main parts of an earthquake.
Focus - the area beneath Earth’s surface where rock that was under stress begins to break or move
Epicenter - the point on the surface directly above the focus
Seismic Waves - vibrations similar to sound waves, which travel through Earth carrying the energy released by an earthquake
Describe a Composite or Stratovolcano.
Steep - sided, symmetrical, medium sized compared to the others, magma and eruptions can vary creating layers, but typically magma is high in silica and has high viscosity, these volcanoes produce the most destructive explosive eruptions
What is the major city near Mount Vesuvius? What is their plan for the next major eruption and why don't the people leave the area?
The major city near Mount Vesuvius is Naples, Italy. They have an evacuation plan in the event of the next eruption which may or may not be a Plinian eruption, unfortunately most people do not know what route they are suppose to take to evacuate the city and scientists are hoping for at least two weeks notice prior to the eruption in order to be able to safely evacuate the area.
The people who live near Mount Vesuvius do not leave for several reasons;
It is their home and the home of their ancestors for generations
The mountain provides fertile soil and the area has a nice climate
Some people do not believe that the mountain is truly a threat and others believe that it is a matter of fate.
Describe a Cinder Cone Volcano.
small, steep-sided, symmetrical, cone shaped, with high silica content and low viscosity producing explosive eruptions