Part I. Consider Figure 1, which shows the vertical component (Z) and horizontal components ( and E) seismograms for a single earthquake. (50 pts) 1. Neatly mark and label the P-wave arrival on the vertical seismogram. (5 pts) 2. Neatly mark and label the S-wave arrival on the horizontal and vertical seismograms. (5 pts) 3. How long after the P-wave arrives does the S-wave arrive? (5 pts) Using the travel time curves in Figure 2, what is the epicentral distance from the earthquake to the station? ( 5 pts) 4. Love and Rayleigh waves are also recorded in the seismograms in Figure 1. a. Mark and label the onset of the Rayleigh wave on the vertical and horizontal-component seismograms. (5 pts) b. Why is it difficult to identify the Love waves on the vertical component seismograms? (5 pts) c. What is the period (time between successive peaks, in seconds) of the first Rayleigh waves to arrive? Label on the seismogram where you measured it. (5 pts) d. What is the period of the Rayleigh waves at the end of the wave train? Label on the seismogram where you measured it. (5 pts) e. Why does the period change and what is this phenomenon called? (5 pts) Figure 1. This figure shows seismograms from a seismic station in Palisades, New York as it recorded an earthquake on 23 June 1965. The earthquake shown here was a magnitude 6.5 event in the Gulf of Alaska. Here, the record marked Z refers to the vertical component and N (orth) and E(ast) are the horizontal components. Each component records the wave arrivals in time; here, to fit the entire wavetrain on a single page, the waves are recorded in time like a typewriter: time goes across the page until it hits the end, then continues on the next line. Here, 1 horizontal inch represents approximately 4 minutes in time. Figure 2. This figure illustrates the time it takes for different seismic phases to travel a given distance; we call these travel-time curves. When a large earthquake occurs, it is recorded at many seismic stations around the globe. If we know where the earthquake occurred - the hypocenter we can compute the distance between the hypocenter, which is the source of the energy, and each seismic station, which is the receiver of the energy. If we know the time when the earthquake occurred - the origin time - we can compute how long it took for each phase to arrive at a given station. For example, if we consider a large earthquake in California and a single seismic station in Iceland, we can look at the seismogram in Iceland and determine when the P-wave arrived. This yields a single point on this figure. If we repeat this process for many earthquakes and many stations, we obtain the curves shown above..

1. Part I. Consider Figure 1, which shows the vertical component (Z) and horizontal components (
and E) seismograms for a single earthquake. (50 pts) 1. Neatly mark and label the P-wave arrival
on the vertical seismogram. (5 pts) 2. Neatly mark and label the S-wave arrival on the horizontal
and vertical seismograms. (5 pts) 3. How long after the P-wave arrives does the S-wave arrive?
(5 pts) Using the travel time curves in Figure 2, what is the epicentral distance from the
earthquake to the station? ( 5 pts) 4. Love and Rayleigh waves are also recorded in the
seismograms in Figure 1. a. Mark and label the onset of the Rayleigh wave on the vertical and
horizontal-component seismograms. (5 pts) b. Why is it difficult to identify the Love waves on
the vertical component seismograms? (5 pts) c. What is the period (time between successive
peaks, in seconds) of the first Rayleigh waves to arrive? Label on the seismogram where you
measured it. (5 pts) d. What is the period of the Rayleigh waves at the end of the wave train?
Label on the seismogram where you measured it. (5 pts) e. Why does the period change and what
is this phenomenon called? (5 pts) Figure 1. This figure shows seismograms from a seismic
station in Palisades, New York as it recorded an earthquake on 23 June 1965. The earthquake
shown here was a magnitude 6.5 event in the Gulf of Alaska. Here, the record marked Z refers to
the vertical component and N (orth) and E(ast) are the horizontal components. Each component
records the wave arrivals in time; here, to fit the entire wavetrain on a single page, the waves are
recorded in time like a typewriter: time goes across the page until it hits the end, then continues
on the next line. Here, 1 horizontal inch represents approximately 4 minutes in time. Figure 2.
This figure illustrates the time it takes for different seismic phases to travel a given distance; we
call these travel-time curves. When a large earthquake occurs, it is recorded at many seismic
stations around the globe. If we know where the earthquake occurred - the hypocenter we can
compute the distance between the hypocenter, which is the source of the energy, and each
seismic station, which is the receiver of the energy. If we know the time when the earthquake
occurred - the origin time - we can compute how long it took for each phase to arrive at a given
station. For example, if we consider a large earthquake in California and a single seismic station
in Iceland, we can look at the seismogram in Iceland and determine when the P-wave arrived.
This yields a single point on this figure. If we repeat this process for many earthquakes and many
stations, we obtain the curves shown above.