Transcript Roy G Biv HW due 4/22/14 • Please view the slideshow.

Roy G Biv HW due 4/22/14
• Please view the slideshow. You may complete the
virtual lab on the website on the following slide if
you’d like
• The purpose of this slide show is just to familiarize you
with the steps of locating an epicenter.
• Complete the time subtracting and epicenter distance
tasks on a separate sheet of paper. (
is )
• YOU MUST SEE THE ENTIRE POWERPOINT and
know the steps, so that you can do the activity in class
on Wednesday!
(do the reading and have fun you don’t have to do the questions . This activity is not required but is fun!)
this activity
required
Pangea Virtual Lab
Click the link below and complete the virtual lab
http://www.glencoe.com/sites/common_assets/science/virtual_labs/ES11/ES11.html
Finding Epicenters
60s
29 m +60
-
S Wave
30m X
00s
X
P Wave
22m 20s
S wave is always the bigger # so
it always goes on top
7m 40 s
• When subtracting time, be sure to
borrow
60 seconds as shown!
• Show every ridiculous step.
• Try the time subtraction problems on
the following slides. Did you get the
accepted answer?
(if necessary)
2:33:00
2:35:30 – 2:33:00 =
2:35:30
00:02:30
2:35:10
2:39:20 – 2:35:10 =
2:39:20
00:04:10
2:32:10
2:34:00 – 2:32:10 =
2:34:00
00:01:50
NOW you try! Show ALL
WORK
How to use the P & S
Wave Chart
• We don’t know when
the EQ started.
• But we know how
much time there was
between the P&S
wave arrivals.
• Let’s say 0:04:00
• C’mon let’s say it!
• We have to find a spot
on the graph where
P&S (careful!) are
separated by 4:00.
• Then drop straight
down to see the
distance to the
epicenter.
2,600km
• Now that we know the
EQ was 2,600km
away, when did it
start?
To travel 2,600km, a P-wave…
needs 5:00 minutes
Back to the lab…
• The difference in
arrival time for
Chicago is 0:02:30.
• That means that
1,400 km
Chicago is ______
from the epicenter.
• Now that we know the
EQ was 1,400km
away, when did it
start?
To travel 1,400km, a P-wave…
needs 3:00 minutes
• If the P-wave was detected at 2:33:00 and
needed 3:00 minutes to travel it must have
started at…
2:33:00
-3:00
2:30:00
1,400km
The EQ happened
somewhere on this line
x
The
Epicenter is
where all 3
circles
intersect!
Ta Da!
If you get a nice
epicenter, you do the
VICTORY DANCE!
The End