1. Why do seismic waves undergo refraction(bending) as they pass through Earth? If the waves didn't bend. what would they indicate about Earth's interior structure?
2. What is the reason why a scientist cannot simply drill down to Earth's mantle to determine Earth's internal composition?
1. Earth interior is both laterally and vertically layers are different composition.
We know earth interior is different composition of rocks and different type of rock behaves differently character inside the earth.
As we go earth interior both temperature and pressure increase. Due to these two factors rock character change in interior.
As pressures increase with depth rock or minerals density increase becuase stress acting overlaying materials.
From earth surface to inside the rocks impedance increase.
When seismic waves move downward it's velocity increase gradually with increase with depth when seismic wave one layer to another layer as results wave bends.
- if seismic waves doesn't bend inside the earth . If earth interior rocks will have same composition and homogeneous character. So seismic waves will move same velocity with all layer inside the earth and moves straight .As results seismis waves will not bend.
2. Earth mantle temperature is 1200°C to 4000°C . Rocks are very hard.
Inside the earth rock density increase with depth as a result rock becomes more hard . So much much of hard rock drill not is possible. In greater depth drilling is impossible. High temperature of rock will melt the drill bits or pipe.
Maximum drill happened 11 km inside the earth.
1. Why do seismic waves undergo refraction(bending) as they pass through Earth? If the waves didn't...