Plate Boundries Flashcards
What processes occur at plate boundaries that impact earthquake magnitude?
The processes occurring at plate boundaries affect the magnitude of earthquakes.
These processes include the movement of tectonic plates, which can lead to stress accumulation and release.
How do the properties of magma influence volcanic eruptions?
The properties of the magma play a crucial role in determining the magnitude and frequency of eruptions.
Factors such as gas content, viscosity, and temperature are significant.
What characterizes earthquakes at divergent boundaries?
Earthquakes tend to be small and short at divergent boundaries.
These earthquakes typically have low magnitude.
What is the nature of volcanic eruptions at divergent boundaries?
Eruptions at divergent boundaries tend to be small and effusive.
Effusive eruptions involve the flow of lava rather than explosive activity.
What type of lava is usually involved in eruptions at divergent boundaries?
The eruptions are usually of basaltic lava.
Basaltic lava is characterized by low gas content, low viscosity, and higher temperature.
Define effusive eruptions.
Eruptions involving the flow of lava rather than explosive activity.
This type of eruption is common at divergent boundaries.
What are the characteristics of basaltic lava?
- Low gas content
- Low viscosity
- Higher temperature
These properties contribute to the nature of eruptions at divergent boundaries.
What are convergent boundaries?
Boundaries where tectonic plates move toward each other, often resulting in subduction and the formation of mountains.
What is the primary geological activity associated with subduction zones?
Earthquakes and volcanic eruptions.
What type of eruptions are commonly associated with subduction zones?
Violent eruptions.
What type of lava is often produced during violent eruptions?
Rhyolite lava.
Fill in the blank: The zone where most friction and pressure build up occurs in subduction zones is called the _______.
[Benioff zone]
What is the relationship between gas content and the type of eruptions?
High gas content tends to lead to more explosive eruptions.
What is the rock type typically associated with high viscosity lava?
Rhyolite.
What characteristics describe basalt lava?
- Low viscosity
- Black to dark brown in color.
True or False: All volcanic eruptions in subduction zones are non-violent.
False.
What is seafloor spreading?
The process by which new oceanic crust is formed at mid-ocean ridges and gradually moves away from the ridge.
What does palaeomagnetism study?
The study of the magnetic properties of rocks to understand historical changes in Earth’s magnetic field.
What are the two periods of magnetism identified in seafloor spreading?
A. Period of normal magnetism
B. Period of reverse magnetism
What is ridge push?
A tectonic process that develops due to the elevation of mid-ocean ridges, causing tectonic plates to move away from the ridge.
What is slab pull?
The force exerted by the weight of a sinking tectonic plate at a subduction zone.
Fill in the blank: The lithosphere is composed of the _______ and the uppermost part of the mantle.
[crust]
What is the asthenosphere?
A semi-fluid layer of the upper mantle that allows for the movement of tectonic plates.
True or False: Gravity is a main driving force in plate tectonics.
True
