Transcript Finding the Epicenter of an Earthquake Using the

To Find The
Epicenter of an Earthquake
Using the Difference in Time
Between the P and the S Wave
Follow the Rainbow!
NSF Funded CUNY GK-12 Science NOW Project Copyright David Stolarz, January 22, 2010
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00 08:30:00 00:09:00
7.6 x103 km
The Completed Process
NSF Funded CUNY GK-12 Science NOW Project
00:10:20 08:11:40
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
Fill out the chart below using the three seismograms and the chart on Page 11 of the Earth Science Reference Tables.
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
B
C
Start Simple – Draw a Line Down From the P-Wave to the Time Scale
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
Fill out the chart below using the three seismograms and the chart on Page 11 of the Earth Science Reference Tables.
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
A
B
C
Judge what time the P-wave starts
NSF Funded CUNY GK-12 Science NOW Project
Origin Time of
Earthquake
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
Fill out the chart below using the three seismograms and the chart on Page 11 of the Earth Science Reference Tables.
08:16
17
18
19
A Quarter after 8 O’Clock! And No Seconds!
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
A
B
C
A zoom-in shows P-wave starting at approximately 08:16:00
NSF Funded CUNY GK-12 Science NOW Project
Origin Time of
Earthquake
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
Fill out the chart below using the three seismograms and the chart on Page 11 of the Earth Science Reference Tables.
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
08:16:00
B
C
Put that value in the appropriate box
NSF Funded CUNY GK-12 Science NOW Project
Origin Time of
Earthquake
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
Fill out the chart below using the three seismograms and the chart on Page 11 of the Earth Science Reference Tables.
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
08:21:00
B
C
Repeat the same process for the S-wave.
NSF Funded CUNY GK-12 Science NOW Project
Origin Time of
Earthquake
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
Fill out the chart below using the three seismograms and the chart on Page 11 of the Earth Science Reference Tables.
08:21:00 (S-Wave Time)
-08:16:00 (P-Wave Time)
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
08:21:00
B
C
Calculate the interval between the two wave arrivals at the seisomgraph
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
Fill out the chart below using the three seismograms and the chart on Page 11 of the Earth Science Reference Tables.
08:21:00 (S-Wave Time)
-08:16:00 (P-Wave Time)
00:05:00 (Time Difference)
( 0 Hours, 5 Minutes, 0 Seconds )
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
00:05:00
B
C
Enter that time in the appropriate box
NSF Funded CUNY GK-12 Science NOW Project
Origin Time of
Earthquake
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
00:05:00
B
C
Go to page 11 of your Earth Science Reference Tables for the chart shown above
NSF Funded CUNY GK-12 Science NOW Project
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
00:05:00
B
C
Use the P-S Wave time interval to figure out the distance to the epicenter
NSF Funded CUNY GK-12 Science NOW Project
Scrap Paper
Place Marks at
P-S Wave Interval
Time and at 0.
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
00:05:00
B
C
Create a reference measurement using scrap paper and the P-S Wave value
NSF Funded CUNY GK-12 Science NOW Project
Scrap Paper
Scrap Paper
Slide paper up
and over until the
reference marks
Line up with the
P and S Lines.
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
00:05:00
B
C
Find the proper place where the reference marks match the P and S Lines.
NSF Funded CUNY GK-12 Science NOW Project
Scrap Paper
Lightly, make a
reference mark in pencil
on the reference table
at this place on the P line.
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
00:05:00
B
C
For convenience, make a light pencil mark on the P line for use in the next step
NSF Funded CUNY GK-12 Science NOW Project
.2 . 4 .6 .8
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
00:05:00
B
C
Look straight down from the P line pencil mark and judge the epicenter distance.
NSF Funded CUNY GK-12 Science NOW Project
Lightly, make
reference marks in pencil
On the reference table
at these two places .
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
00:05:00 3.6 x103 km
B
C
Enter that value for the epicenter distance with proper units.
NSF Funded CUNY GK-12 Science NOW Project
Origin Time of
Earthquake
Travel Time (minutes)
00:06:40
00:06:20
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
00:05:00 3.6 x103 km
B
C
Look across at the y-axis to Judge the time value
NSF Funded CUNY GK-12 Science NOW Project
Origin Time of
Earthquake
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
00:05:00 3.6 x103 km
00:06:20
B
C
Enter that value for the epicenter distance with proper units.
NSF Funded CUNY GK-12 Science NOW Project
Origin Time of
Earthquake
ERASE YOUR MARK!
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
00:05:00 3.6 x103 km
Origin Time of
Earthquake
00:06:20
B
C
Erase your pencil mark on the P-wave to keep your reference table clean
NSF Funded CUNY GK-12 Science NOW Project
08:16:00 (P Arrival Time)
00:06:20 (P Travel Time)
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
00:05:00 3.6 x103 km
Origin Time of
Earthquake
00:06:20
B
C
Calculate what time the earthquake happened using the Arrival and travel times
NSF Funded CUNY GK-12 Science NOW Project
MINUS!
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
08:16:00 (P Arrival Time)
- 00:06:20 (P Travel Time)
Distance to the P-Wave Travel
Epicenter
Time
00:05:00 3.6 x103 km
Origin Time of
Earthquake
00:06:20
B
C
Obviously, the earthquake happened earlier than when its was felt miles away
NSF Funded CUNY GK-12 Science NOW Project
08:15:60 (1 min. is 60 sec)
08:16:00 (P Arrival Time)
- 00:06:20 (P Travel Time)
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
00:05:00 3.6 x103 km
00:06:20
B
C
Convert hours to minutes or minutes to seconds when necessary
NSF Funded CUNY GK-12 Science NOW Project
Origin Time of
Earthquake
08:15:60 (1 min. is 60 sec)
08:16:00 (P Arrival Time)
- 00:06:20 (P Travel Time)
08:09:40 (Time at Origin)
Station
A
Arrival Time of Arrival Time of
P-Wave
the S-Wave
08:16:00
08:21:00
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
00:05:00 3.6 x103 km 00:06:20 08:09:40
B
C
Put the calculated time of earthquake in the proper box
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
3.6 x103 km
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00 5.0 x103 km 00:08:20
08:10:40
C
Anything complex is easier when broken into smaller steps
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
A
08:16:00
B
08:19:00
08:21:00
P-S Wave
Interval
00:05:00
Distance to the P-Wave Travel
Epicenter
Time
3.6 x103 km
00:06:20
C
Judge what time the P-wave starts and enter it in the box
NSF Funded CUNY GK-12 Science NOW Project
Origin Time of
Earthquake
08:09:40
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
A
08:16:00
B
08:19:00 08:26:00
08:21:00
P-S Wave
Interval
00:05:00
Distance to the P-Wave Travel
Epicenter
Time
3.6 x103 km
C
Repeat the same process for the S-wave.
NSF Funded CUNY GK-12 Science NOW Project
00:06:20
Origin Time of
Earthquake
08:09:40
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
A
08:16:00
08:21:00
B
08:19:00
08:26:00 00:07:00
00:05:00
Distance to the P-Wave Travel
Epicenter
Time
3.6 x103 km
00:06:20
Origin Time of
Earthquake
08:09:40
C
Use the P-S Wave time interval to set reference marks for the sliding step
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
A
08:16:00
08:21:00
00:05:00
B
08:19:00
08:26:00
00:07:00
Distance to the P-Wave Travel
Epicenter
Time
3.6 x103 km
00:06:20
Origin Time of
Earthquake
08:09:40
C
Create a reference measurement using scrap paper and the P-S Wave value
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
A
08:16:00
08:21:00
00:05:00
B
08:19:00
08:26:00
00:07:00
Distance to the P-Wave Travel
Epicenter
Time
3.6 x103 km
00:06:20
Origin Time of
Earthquake
08:09:40
C
Find the proper place where the reference marks match the P and S Lines.
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
B
08:19:00
08:26:00
00:07:00
5.0 x103 km
00:06:20
Origin Time of
Earthquake
08:09:40
C
Look straight down from the P line pencil mark and judge the epicenter distance.
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
B
08:19:00
08:26:00
00:07:00
5.0 x103 km
00:08:20
C
Look across at the y-axis to Judge the time value
NSF Funded CUNY GK-12 Science NOW Project
Origin Time of
Earthquake
08:09:40
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
Put the calculated time of earthquake in the proper box
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
3.6 x103 km
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00 5.0 x103 km 00:08:20
08:10:40
C
Anything complex is easier when broken into smaller steps
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00 08:30:00 00:09:00
7.6 x103 km
00:10:20 08:11:40
Follow the same overall process for Station C
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00
Judge what time the P-wave starts and enter it in the box
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00 08:30:00
Repeat the same process for the S-wave.
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00
08:30:00 00:09:00
Use the P-S Wave time interval and the y axis of the reference table
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00
08:30:00 00:09:00
Create a reference measurement using scrap paper and the P-S Wave time value
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00
08:30:00 00:09:00
Find the proper place where the reference marks match the P and S Lines.
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00
08:30:00 00:09:00
7.6 x103 km
Enter that value for the epicenter distance with proper units.
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00
08:30:00 00:09:00
7.6 x103 km
00:10:20
Calculate what time the earthquake happened using the Arrival and travel times
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an
Earthquake Using the Difference in
Time Between the P and the S Wave
Using Scrap Paper
Station
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00
08:30:00 00:09:00
7.6 x103 km 00:10:20
08:11:40
Calculate and place the time of earthquake in the proper box
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
A
Z
$
Z
$
B
All three arcs must pass through
the earthquake epicenter, in
this case, the San Andreas fault
in California, USA.
C
5000 km
0
Z
$
Using scrap paper.
3600 km
Use the Station info to locate the epicenter of the earthquake on a map
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
A
Z
$
Z
$
B
C
Station
Z
$
5000 km
0
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00
08:30:00 00:09:00
7.6 x103 km 00:10:20
08:11:40
On the Station Map, Find Station A
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
A
Z
$
Z
$
B
C
Station
Z
$
5000 km
0
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00
08:30:00 00:09:00
7.6 x103 km 00:10:20
08:11:40
Find Station B
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
A
Z
$
Z
$
B
C
Station
Z
$
5000 km
0
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00
08:30:00 00:09:00
7.6 x103 km 00:10:20
08:11:40
Find Station C
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
A
Z
$
Z
$
B
Station
Distance to the
Epicenter
A
3.6 x103 km
B
5.0 x103 km
C
7.6 x103 km
C
Station
Z
$
5000 km
0
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00
08:30:00 00:09:00
7.6 x103 km 00:10:20
08:11:40
Use the Distance to Epicenter for each station
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
A
Z
$
Z
$
B
Station
Distance to the
Epicenter
Distance to the
Epicenter
A
3.6 x103 km
3,600 km
3
B
5.0 x10 km
5,000 km
C
7.6 x103 km
7,600 km
C
Station
Z
$
5000 km
0
Arrival Time of Arrival Time of
P-Wave
the S-Wave
P-S Wave
Interval
Distance to the P-Wave Travel
Epicenter
Time
Origin Time of
Earthquake
A
08:16:00
08:21:00
00:05:00
3.6 x103 km
00:06:20
08:09:40
B
08:19:00
08:26:00
00:07:00
5.0 x103 km 00:08:20
08:10:40
C
08:21:00
08:30:00 00:09:00
7.6 x103 km 00:10:20
08:11:40
Convert scientific notation for the distance to the epicenter for each station
NSF Funded CUNY GK-12 Science NOW Project
or
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
Station
Distance to the
Epicenter
A
3,600 km
B
5,000 km
C
7,600 km
A
Z
$
Z
$
B
Using the scale bar below as the
reference, scribe a circle around
the three points using a
compass, string, or scrap paper.
C
5000 km
0
3600 km
Scribe the arc for Station A using the map scale distance
NSF Funded CUNY GK-12 Science NOW Project
Z
$
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
Station
Distance to the
Epicenter
A
3,600 km
B
5,000 km
C
7,600 km
A
Z
$
Z
$
B
The two circles cross at two
points. A third circle is needed
to confirm the earthquake
epicenter.
C
5000 km
0
5000 km
Scribe the arc for Station B using the map scale distance
NSF Funded CUNY GK-12 Science NOW Project
Z
$
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
Station
Distance to the
Epicenter
A
3,600 km
B
5,000 km
C
7,600 km
A
Z
$
Z
$
B
All three arcs must pass through
the earthquake epicenter, in
this case, the San Andreas fault
in California, USA.
C
5000 km
0
Z
$
Using scrap paper.
3600 km
If the distance is longer than the scale, use scrap paper to extend the scale.
NSF Funded CUNY GK-12 Science NOW Project
Finding the Epicenter of an Earthquake
Using the Difference in Time Between the P and the S Wave
A
Z
$
Z
$
B
All three arcs must pass through
the earthquake epicenter, in
this case, the San Andreas fault
in California, USA.
C
5000 km
0
Using scrap paper.
3600 km
Where the three arcs cross is the epicenter – Circle it!
NSF Funded CUNY GK-12 Science NOW Project
Z
$