Thread: Fwd: earthquake list

Started: 2008-10-02 19:18:57
Last activity: 2008-10-02 19:18:57
Topics: IRIS EPO
Michael Hubenthal
2008-10-02 19:18:57
This response was also supposed to go to the IRISEd list and I forgot
to add it.

---------------------------------
Michael Hubenthal
Education Specialist
IRIS Consortium
607-777-4612
www.IRIS.edu
hubenth<at>iris.edu




Begin forwarded message:

From: Michael Hubenthal <Michael.Hubenthal<at>iris.edu>
Date: October 2, 2008 12:17:14 PM EDT
To: Kate Baker <kbaker<at>stxcountryday.com>, earthscience<at>list.nsta.org
Cc: Michael Hubenthal <Michael.Hubenthal<at>iris.edu>, John Taber
<taber<at>iris.edu>, Tim Ahern <tim<at>iris.washington.edu>
Subject: Re: earthquake list

Hi Kate,

I am pleased that you have been using the IRIS Seismic Monitor
(http://www.iris.edu/dms/seismon.htm) as a resource for your
classroom. As you point out in your note, that tool is designed to
display seismicity for events magnitude 4 and larger for the
purposes of highlighting patterns of global seismicity and the
frequency of earthquake occurrence.

There are a number of other ways to mine the IRIS Data Management
Center for event data with in a set of parameters you define. The
one I would highly recommend to you is a map driven tool called the
IRIS Earthquake Browser or IEB. You can find a link to it here
http://www.iris.edu/data/event/ What is nice about this tool is
that you can define a region of interest by defining a box on the
map and then use the controls on the right to set limits on
Magnitude, Depth and Time range (NOTE: there is also a drop down
that limits the number of events displayed. As a default this is
set to 200 to keep the data volume from becoming too great at the
start). Once you have the data set displayed that is of interest
to you, click the word "table" at the top and the data will be
displayed in an table on a web page (I would like to see an xls
option added as well). This should fit your needs very nicely and
is extremely easy to use... even for your students!

NOTE: As a caveat to the type of data you noted you wanted to use
with students (<M 2.0), you will need to be careful about the
magnitudes you use in your studies with students. The locating of
small events is limited by the density of stations nearby to record
the events, e.g. a M 2.0 release a relatively small amount of
energy that can attenuate before it travels far enough to be
detected by an instrument. Thus, if you create a global map of
events in the IEB for events M 2.0 or smaller, you would get a map
of where there are dense arrays of stations on Earth, rather then
where there are actually large numbers of small events. (You
should definitely try this with your students to see if they think
the distribution they see makes sense). Thus, for a global study
you should probably limit the magnitudes to 4 or 4.5 or greater.
Conversely if you limit your study to an area like Southern CA or
Japan, you could extend the bottom threshold much further. I hope
this makes sense, but if not, please feel free to email me with
questions.

Best Wishes,
Michael

---------------------------------
Michael Hubenthal
Education Specialist
IRIS Consortium
607-777-4612
www.IRIS.edu
hubenth<at>iris.edu




On Oct 2, 2008, at 10:29 AM, Kate Baker wrote:

[NSTA Earth Science]
I want to have my students look at earthquake data for the past
year. I'm using the list at
http://www.iris.washington.edu/seismon/last30days.phtml

but i wondered if anyone knew where the data might be for the
last year. I'd also love to see a list of earthquakes that show
even small ones, less than 2.

I'm having them look at the data in Fathom to see if there is a
relationship between plate boundary and depth and magnitude.
Also, the distribution of magnitude.

Thank you!

Kate Baker
St. Croix Country Day

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