Earthquakes and Seismic Waves Flashcards
What are the properties of the inner core?
Very hot and dense solid iron
What are the properties of the outer core?
very hot, dense, liquid, mostly iron
What are the properties of the mantle?
Very hot, less dense and a mixture of solid and molten rock
What are the properties of the crust?
Very thin layer of solid rock
How are earthquakes caused?
AS two plates slide past one another, friction between them prevents them from moving, eventually the frictional forces cannot keep them still and they slip. The immense energy stored in the compressed plates us released in the form of seismic waves.
What evidence supported Alfred Wegener’s idea of the movement of the earth’s crust in 1915?
- ancient rocks found in East Asia were identical to those found in South America
- Fossils found in both regions were from the same species of ancient aquatic reptil
What are the properties of P waves?
They are longitudinal, fast, travel in solids and liquids
What are the properties of S waves?
The are transverse, slow, travel in solids
What are the properties of L waves?
The are transverse, longitduinal, very slow, travel in solids and liquids.
Why are earthquakes tsunamis unpredictable?
- The pressure between the tectonic plates cannot be measured
- the fault lines are often deep within the earth’s crust
How do scientists make predictions of the risk of earthquakes happening in a specific area?
They use the earthquake history
How can the distance from the seisometer to the epicenter of the earthquake be calculated?
From the time delay of recieving the P and S waves and their speeds
