Jökull - 01.01.2020, Page 69

Einarsson and Jakobsson
Table 2. Duration magnitude scale for analog stations,
Mτ = a log τ – b.
Station 4-code a b R N
Skammadalshóll ICSK 2.1 0.5
Hafursey ICHF 2.4 0.9
Selkot ICSE 2.6 1.2
Snæbýli ICSB 2.2 0.5
Árgilsstaðir ICAR 1.8 0.4
Selfoss ICSL 2.3 1.3
Kvísker ICKV 2.39 0.56 0.89 49
Litla-Hekla ICHE 2.8 2.6
Hellar ICHL 2.7 1.2
Svartsengi ICTH 2.5 1,2
Valahnúkar ICVA 2.3 1.6
ÍR-skáli ICIR 2.9 2.4
Laugarvatn ICLV 2.3 0.1
Ljótipollur ICLJ 2.0 0.5
Sporðalda ICSP 2.2 0.3
Jökulheimar ICJO 2.2 0.6
Vonarskarð ICVO 2.5 1.1
Hveravellir ICHV 2.2 0.6
Miðfell ICMI 2.54 0.68 0.96 61
Aðalból ICAB 2.40 0.56 0.93 65
Svartárkot ICSV 2.75 1.09 0.91 96
Grímsstaðir ICGS 2.29 0.44 0.96 34
Reynihlíð ICRI 3.00 1.66 0.93 86
Húsavík ICHU 3.0 2.1
Skinnastaður ICSS 2.46 0.75 0.89 67
Hraun ICHS 3.30 2.11 0.90 66
Siglufjörður ICSI 3.17 1.86 0.93 85
Leirhöfn ICLN 3.36 2.47 0.88 66
Grímsey ICGR 2.75 1.26 0.87 59
THE SCANNING PROJECT
The purpose of the scanning project was mainly
twofold: 1) to preserve the seismogram archives, and
2) to make the seismograms accessible to researchers
for studies. On more than one occasion, collections of
seismograms had been close to destruction when col-
leagues were re-organizing store rooms and offices.
The threat of flooding or fire was also considered. The
seismograms had been stored in the archives of the in-
stitutes that collected them and the National Archives,
but they had never all been stored in the same place.
Finding records of a particular event was almost an
impossible task. Having all the seismograms acces-
sible on an open website would greatly facilitate re-
search on seismicity and volcanism. An initiative by
the Institute of Earth Sciences was well received and
a decision was made in early 2017 to join forces and
start a four-year program to scan and computerize all
available analog seismograms. The participating in-
stitutions were: Institute of Earth Sciences, Science
Institute, University of Iceland, Icelandic Meteoro-
logical Office, Natural Catastrophe Insurance of Ice-
land, National Power Company of Iceland, Reykja-
vík Energy, Icelandic National Archives, Rannís, the
Icelandic Centre for Research, and The Eggert Briem
Fund, University of Iceland.
Figure 6. Duration of selected earthquakes at the
Miðfell station plotted against the local magnitude de-
rived from the calibrated stations in Reykjavík, Akur-
eyri, Sida and Eyvindará. – Stærð skjálfta sem komu
fram á mælum Landsnetsins mátti ákvarða út frá
varanda hreyfingarinnar, τ , þ.e. tímanum sem leið frá
fyrstu bylgju og þangað til hreyfingin dó út. Mælarnir
voru kvarðaðir með tilliti til eldri mæla, í Reykjavík, á
Akureyri, Kirkjubæjarklaustri og Eyvindará. Myndin
sýnir hvernig varandi á mælinum á Miðfelli var háður
stærð. Línan er kvörðunarkúrfan sem felld er að
mæligögnunum.
Several criteria were set for the project:
1. The quality of the scanned records should be com-
parable to that of the originals.
2. The scanned records should be available and easily
accessible to everyone interested.
3. The scanning files should be of manageable size to
allow a quick overview of their content.
The scanning began in late 2017 in the facilities
of the National Archives with a large-format scanner
provided by the Eggert Briem Fund. The work was
66 JÖKULL No. 70, 2020