Geoscience Reference
In-Depth Information
then considered earthquakes that killed a lot of people from Utsu's deadly earth-
quakes list (Utsu 2002), and added some smaller events of seismological interests.
Since this initial list had about 250 events, Lee sorted them by Flinn-Engdahl regions
(FER) (Flinn et al. 1974) and chose at least one event (the largest if more than one
is available) in each region.
Because the list contains 151 earthquakes, about 50% more than that could be
scanned, Lee circulated the list to about 20 earthquake seismologists worldwide for
comments and suggestions. Since no one proposed to delete any earthquakes on the
list, Lee downsized the list by choosing fewer events after 1970. The final list of
117 earthquakes selected for the USGS/ICSU scanning project is given in Table 1.
The station selection was made by C.R. Hutt so that stations are well-distributed
globally, in addition to being either the current digital GSN stations or reasonably
proximal to one (distance indicated in the table, if applicable), and a listing of the
selected WWSSN stations is given in Table 2.
5 The SeismoArchives Project
In the past decade, modern information technology (including the World-Wide Web
and the Internet) has made it possible to archive large volumes of data with back-end
data storage for easy online search and access. Therefore, we take one step beyond
scanning and preserving occasional analog seismograms. A new project termed the
“SeismoArchives” utilizes these new technologies to make scanned seismograms
and related materials readily accessible as online source material, suitable for re-
search. The primary goal of the SeismoArchives project is to create online seis-
mogram archives of significant earthquakes of the world. Unfortunately, because
no funding is yet available for constructing these SeismoArchives, we depend on
volunteers and donations of data files and/or financial support for scanning analog
seismograms that date back as far as 1882.
These analog seismograms (about 50 millions pieces) have been disappearing
at an alarming rate. We are now concentrating on preserving a small fraction of
the seismograms recorded by the World-Wide Standardized Seismograph Network
(Oliver and Murphy 1971) in the 1960s and 1970s (about 4 million seismograms
on 70 mm film chips), and of the seismograms microfilmed by the Historical Seis-
mogram Filming Project (Glover and Meyers 1988) in the 1980s (about 0.5 million
seismograms on microfilms for earthquakes prior to 1963).
5.1 The IRIS Data Management Center
The Data Management Center (DMC) of IRIS is hosted by the University of
Washington's Earth and Space Sciences Program in Seattle, Washington, USA. The
IRIS DMC receives seismic data from nearly 100 networks worldwide. It archives
more than 40 years of digital data, although almost most of them are from the past
Search WWH ::
Custom Search