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Complete the sentence by putting a cross (X) in the box next to your answer - Edexcel - GCSE Physics - Question 4 - 2013 - Paper 1
Question 4
Complete the sentence by putting a cross (X) in the box next to your answer. Waves from an earthquake are ☐ A transverse waves only ☐ B electromagnetic waves only ... show full transcript
Worked Solution & Example Answer:Complete the sentence by putting a cross (X) in the box next to your answer - Edexcel - GCSE Physics - Question 4 - 2013 - Paper 1
Step 1
Step 2
Describe how this thermal energy can cause earthquakes.
Answer
The thermal energy from the Earth's interior drives convection currents in the mantle. These currents cause tectonic plates to move. When these plates interact at their boundaries, they can become locked due to friction. When the stress exceeds the frictional resistance, it releases energy in the form of seismic waves, causing an earthquake. This process exemplifies the dynamic nature of the Earth’s crust.
Step 3
Use the chart to estimate the S – P time for the earthquake waves shown.
Answer
By analyzing the chart, we can see the arrival time of the first P wave and the first S wave. The S – P time is the difference in arrival times. If the first P wave arrives at approximately 100 seconds and the first S wave arrives at approximately 150 seconds, then
S - P time = 150 seconds - 100 seconds = 50 seconds.
Step 4
Use the S – P time to estimate the distance between the monitoring station and the epicentre of this earthquake.
Answer
Given that the S – P time for the earthquake is 20 seconds, we can use the provided graph to find the corresponding distance. By locating 20 seconds on the S-P time axis, we can trace up to intersect with the S-wave line, which indicates a distance of approximately 140 km.
Step 5
Describe what is meant by infrasonic waves.
Answer
Infrasonic waves are low-frequency sound waves that have a frequency below 20 Hz. They are typically not heard by the human ear but can be detected by sensitive instruments. In the context of earthquakes, these waves are associated with movement in the earth and can travel long distances.