Geography Revision Flashcards
(8 cards)
How does evidence support plate tectonics theory?
There are similar rock types are found far away from each other. There are fossils of animals that are on different continents and have no way to be near each other. There is a jigsaw fit of all the continents. There are also convection currents.
why are earthquakes and volcanoes found near plate boundaries
At diverging plate boundaries, earthquakes occur as the plates pull away from each other. Volcanoes also form as magma rises upward from the underlying mantle along the gap between the two plates. We almost never see these volcanoes, because most of them are located on the sea floor.
how earthquakes and volcanoes occur at Destructive plate boundaries
A destructive plate margin usually involves an oceanic plate and a continental plate. The plates move towards one another and this movement can cause earthquakes. This happens because the oceanic plate is denser (heavier) than the continental plate. When the plate sinks into the mantle it melts to form magma.
how earthquakes and volcanoes occur at Constructive plate boundaries
At a constructive plate margin the plates move apart from one another. When this happens the magma from the mantle rises up to make (or construct) new land in the form of a shield volcano. The movement of the plates over the mantle can cause earthquakes.
Explain the effects of the Montserrat volcano
During this time, Montserrat was devastated by pyroclastic flows .Volcanic eruptions and lahars have destroyed large areas of Montserrat. The capital, Plymouth, has been covered in layers of ash and mud. Many homes and buildings have been destroyed, including the only hospital, the airport and many roads.
Effects/facts of the Montserrat volcano
The Soufriere Hills volcano is a stratovolcano on the island of Monserrat in the Caribbean Sea. It is a very powerful volcano that became active in 1995 and which had a huge eruption in 1997, destroying the southern part of the island and the capital city of Plymouth with volcanic ash and hot pyroclastic flows.
human and physical factors caused the Haiti earthquake to be so destructive
The Haiti earthquake occurred at a fault that runs right through Haiti and is situated along the boundary between the Caribbean and North American plates, which are rocky slabs that cover the planet and fit together like a giant jigsaw puzzle. These two plates constantly creep past one another, about 0.8 inches a year, with the Caribbean plate moving eastward with respect to the North American slab.
Twenty millimeters a year of slippage is very small, and that’s not what people said, geophysicist with the U.S. Geological Survey (USGS) and the National Earthquake Information Center (NEIC).
Rather, they felt the release of energy from the Enriquillo-Plaintain Garden fault system.The two sides of the fault line moved past each other in an east-west direction and that’s what caused the energy release and the Haiti earthquakes.
The high magnitude of this quake took scientists by surprise, as this system of faults hasn’t triggered a major temblor in recent decades. The fault has, however, been linked to some historical big ones in 1860, 1770, 1761, 1751, 1684, 1673 and 1618, though none of these has been confirmed in the field as associated with this fault, according to the USGS.
Explain the cause of a Tsunami
A tsunami is a large ocean wave that is caused by sudden motion on the ocean floor. This sudden motion could be an earthquake, a powerful volcanic eruption, or an underwater landslide. The impact of a large meteorite could also cause a tsunami.
