An earthquake occurred 6 kilometers below the surface of the earth, just south of the San Francisco Bay, as shown in Figure 1.
The energy released radiates outwards from the focus.
Seismograms record how the energy affects different areas. Figure 2 shows seismograms from different locations around the Bay area that recorded the earthquake. Look at the information from the seismograms locations in figure 2 and answer the questions below.
- How many seismograph locations are shown?
- Why are they spread out and not all in the same place?
- Which location felt the earthquake first?
Which location felt the earthquake last?
- Which area had more energy recorded?
Which location had the least?
- When did the first wave hit each of the areas (seconds after the earthquake).