Zero-Order Seismology
GETTING TO KNOW AMASEIS
2008 Seismograph Operators Workshop
October 19-21, 2008
University of Missouri at Kansas City
Prepared by Kay D. Wyatt ([email protected])
This hands-on session is designed to get you going before you even receive your new AS-1
seismometer! You will be able to install AmaSeis, find files in the AmaSeis file structure, locate
earthquakes using the internet, make a station-event log, and plot earthquake locations on a
world map. So, let’s get started!
When following the instructions on this document, you will be frequently directed to resources on
the Internet. We want you to get comfortable with the IRIS Website because it is an excellent
central location for the AS-1 resources you need. So, rather than direct you to the specific page
on the IRIS website, we’ll show you how to navigate to the page of interest. These navigation
hints will be shown in a text box. So here is our first navigation hint:
NAVIGATION HINT #1
Finding the AS-1 resources on the IRIS Website
Start at the main IRIS Website
www.iris.edu
Next, click on the left menu bar button labeled “For Educators”
Next, click on “School Seismographs”
We’ll call this the “IRIS Seismograph Page”
INSTALL AMASEIS
Our first step will be to install AmaSeis. You will find detailed instructions on how to install
AmaSeis in the AmaSeis Manual. To find this on the internet…
NAVIGATION HINT #2
AmaSeis/AS-1 Manual
Start at our “IRIS Seismograph Page” (see HINT #1)
Click on “AS1 User Resources” on the left menu bar.
Next, click on “Manual (download)”
The AmaSeis instructions are in Section 3 and 4. It would be redundant for us to repeat these
instructions in this document. So for this hands-on session, we just want to make sure you know
how to find the information on the internet.
In addition to the manual, there are wonderful instructional videos which walk you through the
installation of AmaSeis. They are located at:
NAVIGATION HINT #3
Instructional Videos
Start at our “IRIS Seismograph Page” (see HINT #1)
Click on “AS1 User Resources” on the left menu bar.
Next, click on “Instructional Videos”
Note that these videos can help you install your AS-1 seismograph as well. They are especially
helpful if you aren’t able to immediately install the AS-1 when you get home. So, don’t worry
about remembering everything!
WHAT IS AMASEIS
The AmaSeis program is used to record and archive data from the AS-1 Seismometer.
Additionally, AmaSeis can be used to view, save, filter, analyze and interpret seismograms.
For this session, we will use AmaSeis as a viewer for display, analysis, and interpretation of
earthquake seismograms without an attached AS-1 seismometer.
AMASEIS FILE STRUCTURE
The default installation location for AmaSeis is at “C:\Amaseis”. After installation, this folder
initially looks like this:
Figure 1:
Before we actually run AmaSeis, we want to load data from the CD that you have been
provided with. By the way, the data on your CD is also available on the Internet at Larry
Braile’s Website at http://web.ics.purdue.edu/~braile/edumod/as1lessons/as1lessons.htm.
Just go to Lesson 13 on that web page and follow the directions to download the data. Be
sure to download the file named “EqList.xls”. This is an Excel spreadsheet where Larry
highlights all of the earthquakes available in this dataset. The data on the CD goes through
March of 2008. So, keep checking Larry’s website for the latest data.
Now, back to our lesson. Insert your CD. Then click on “My Computer” and select the device
where the CD is located.
On this CD, you will see a folder that contains the data. It will look something like this.
Click “Edit” and then “Select All”. Then, click “Copy”. Now go to the folder where AmaSeis
was installed and click “Edit” and then “Paste”. Your AmaSeis folder will now look like:
You now have seismic data for 2004 through March of 2008! Let us look at the files in more
detail. First, double-click on the folder called “2008”. You will now see:
Each folder corresponds to each month of 2008. The folder “01” corresponds to January, “02”
corresponds to February, and “03” corresponds to March.
Next, double-click on the file “01” or the January data:
Now, each folder corresponds to a day of the month (January). The data on the CD have been
compressed by only keeping the days for which there was an earthquake. Let’s look at the 5th
day of the month by double-clicking on the folder named “05”.
Now, you see one file for each hour of the day!
files.
The seismic data is stored in what we call “Z”
You might ask yourself why knowing the Amaseis file structure is important. There are several
reasons. For example, you might have limited disk space and only want to keep the files
where you have recorded earthquakes. You can delete the days without earthquakes.
Another case where you would want to understand the file structure is if the kids get rowdy one
day and knock against the seismometer cause a “kid quake”. You may not wish to keep this
kind of quake in your data files. So, you can simply delete the “Z” file for the hour of the “kid
quake”!
SAC FILES
The Z files contain the day to day recordings of your seismometer. But, suppose you recorded
a spectacular earthquake and wanted to share it with other schools. A single earthquake is
saved in what is called a “SAC” file. There are several available to you in the AmaSeis
directory.
I personally prefer to keep my folders organized, so I created a folder named “SAC” and keep
all my SAC files there. Let’s do that. First, click on “File” and then “New” and then “Folder”.
Give the folder the name “SAC”.
Next, let’s move all the SAC files to the SAC folder. The easiest way is just “drag and drop”.
Click on one of the SAC files and keep holding the left mouse button down. Then drag that file
till it “rests” over the SAC folder. Then release the left mouse button. Do this for all the SAC
files. Your SAC folder now looks like:
EXCELLENT! Now we are ready to run AmaSeis!
BASIC AMASEIS OPERATION
In this session, we will be demonstrating several of the most basic features of AmaSeis. We
will list them here. But you can find details on these operations in the AmaSeis Manual (see
Navigation Hint #2).
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Helicorder Screen Overview
Changing the port setting
Setting Station Parameters
Instrument Settings
Searching for events
Saving an Event (Use format: yymmddhhmmstcode.sac)
For our practice sessions, we will be looking at the January 13, 2007, earthquake East of the
Kuril Islands. This was an 8.2 magnitude earthquake located at Latitude of 46.29 and
Longitude of 154.45. On the top menu bar for Amaseis, click “Settings” and then “Go to DateTime”. Then set the date and time as follows.
Next, click on “Settings” on the top menu bar and select “Helicorder”. Make sure that the
horizontal time limit is “one hour”, the gain is set to “10”, and the “Filter” option is turned on.
Now click on the button “Filter out high frequencies”. Turn on the “Filter out high frequencies”
by clicking the box to its left. Then type in a “1” in the Cut-off period. This will filter out any
frequencies higher than 1 Hz (cycle per second). Then click “OK”.
Back in the Helicorder window (continuous record dialog) click on the button “Filter out low
frequencies”. Turn on the “Filter out low frequencies” by clicking the box to its left. Then type
in a “20” in the Cut-off period. This will filter out any data with a period longer than 20 seconds
(frequencies lower than 0.05 Hz).
THE HELICORDER SCREEN
Now, the Amaseis screen should look like the screen capture below.
The horizontal axis is in minutes from 0 to 60 minutes. So each line on the display shows one
hour. On the axis to the left is listed each hour of the day, from 0 to 23 hours. You read the
Amaseis data like a book starting at the top left and reading to the top right. Then you drop
down a line and start reading on the left at the next line. You can see that when we display the
data at one hour per line, we display an entire 24 hour period.
If you move your mouse to the onset of the earthquake, look at the box on the lower left and
you will see that it starts at 04:35:16 or, the fourth hour, 35 minutes and 16 seconds. The day
is shown at the upper left as 2007/01/13.
It is important to note that Amaseis uses UTC or Universal Time Coordinates. To convert to
your local time use the following table:
Local Time
Subtract
from UTC:
Atlantic Standard
Atlantic Daylight
Eastern Standard
Eastern Daylight
Central Standard
Central Daylight
Mountain Standard
Mountain Daylight
Pacific Standard
Pacific Daylight
Alaskan Standard
Alaskan Daylight
Hawaiian Standard
Four hours
Three hours
Five hours
Four hours
Six hours
Five hours
Seven hours
Six hours
Eight hours
Seven hours
Nine hours
Eight hours
Ten hours
EXTRACTING EVENTS
Now let us look more closely at this earthquake. Move your cursor till it points a few minutes
before the earthquake. Click and hold the left mouse button. Then drag the cursor till it
captures about 160 minutes (2 hours 40 minutes). Next click on the icon below shown by the
red arrow.
This brings up a new display showing an enlarged version of our earthquake. If you want to go
back to the main Amaseis display, click the “BACK” button.
Now, let’s save this earthquake as a SAC file which you can easily share. When saving SAC
files it is best to save it in the format “yymmddhhmmstcode.sac” where “yy” is the year, “mm”
the month, “dd” the day, “hh” the hour, “mm” the minute, and “stcode” as the station code. My
station code is “OSOR” so I will save it as “0701130435OSOR.sac”.
SHARING AND RETRIEVING DATA
One of the most enjoyable aspects of having a seismograph is the ability to share your data.
But, you should first register your station. To do this, follow the procedure on the webpage
below.
NAVIGATION HINT #4
REGISTERING YOUR SEISMOGRAPH
Start at our “IRIS Seismograph Page” (see HINT #1)
Click on “AS1 User Resources” on the left menu bar.
Next, click on “Register your AS-1”
Let’s next look at the IRIS resources for sharing data. To do this, go to the webpage below.
NAVIGATION HINT #5
SHARING DATA
Start at our “IRIS Seismograph Page” (see HINT #1)
Click on “AS1 User Resources” on the left menu bar.
Next, click on “Download Data”
This takes you to the Data Sharing website for the IRIS Seismographs in Schools Program.
From here you can update your school’s information, look at real time images of many of the
school’s seismographs, investigate earthquakes, and upload and download data.
Let’s look first at the all the schools who have registered their seismographs by clicking on the
“Schools” button. Note that the station name of each school is listed in the left column. And,
YOUR school will be here soon!
Next, click on the “Earthquakes” button. This is the “Download Data” section. If you scroll
down the list, you can see the earthquake events for which schools have uploaded their data.
Let’s look at our earthquake East of the Kuril Islands. To do this click on the hyperlink “2007”.
Then scroll down to January 13 and click on the hyperlink “East of the Kuril Islands”.
This brings up a screen which shows the location of this earthquake along with all the school
seismograph stations that have uploaded their data. Scroll down and click on the “View all
seismograms for this event” hyperlink. Now you can see this event for all the stations. If
you scroll down to the bottom of the page, you will see Larry Braile’s station “WLIN”.
Let’s click on the “Download SAC Data” for the station “BHUK” which is a high school in the
UK. The file download widget pops up. Click on the “SAVE” button. This brings up the File
selection widget. Go to the AmaSeis folder at C:\Amaseis. Then double-click on the folder
named “SAC”. Then, click on the “SAVE” button.
Now, go back to the AmaSeis program. Click on “File” and then “Open”. Go to your SAC
folder and click on the file you just downloaded named “0701130440bhuk.sac”. Your screen
will look like this:
You are now looking at the recording of our earthquake made on a seismograph in the UK!
AS-1 USERS MAILING LIST
One very important resource that you will surely want to take advantage of is the AS-1 Users
Mailing List. Here you can post questions or report information to the entire IRIS
Seismographs in Schools contacts. You’ll get up to the minute notices on new IRIS resources
and help to solve the problems you encounter. To register for this list just go to the IRIS
Seismograph in Schools web page (See Navigation Hint #1).
CONGRATULATIONS!
Congratulations! You have just opened the window into the world of earthquakes!
Don’t forget that you can do all of these activities even before you set up your AS-1
seismometer. Your students might enjoy seeing immediately how they can look at
earthquakes from school seismometers all over the world!
HAPPY QUAKING!