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Collection of instrumental parametric data from printed seismological station bulletins

D. Di Giacomo, D.A. Storchak, A. Villaseñor and J. Harris

IUGG 2015 Prague, Session JA6

BackgroundThe ISC and a Team of International Experts released in January 2013 the ISC-GEM catalogue (1900-2009), which provides basic earthquake parameters (location, moment magnitude, and, if available, moment tensor) along with corresponding uncertainties.

This product is unique since list parameters obtained using the same techniques (to the largest extent possible) throughout the last 110 years of instrumental seismology.

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www.isc.ac.uk/iscgem/ or

http://colossus.iris.washington.edu/iscgem/

Background

Given the time and resources in the project we processed only selected earthquakes using time-variable cut-off magnitudes:

• M ≥ 7.5 up to 1917 (plus significant quakes in continental regions with M ≥ 6.5);

• M ≥ 6.25 between 1918 and 1959 (currently being extended down to ~ 5.5)• M > 5.5 from 1960 onwards.

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To process large earthquakes occurred in the last 100+ years we first had to

digitize the necessary instrumental parametric data (hypocenters,

magnitudes, phase time arrivals, amplitude and periods of different phases, etc.) in order to apply the same modern techniques we use

for current earthquakes also to past ones.

A timeline of instrumental seismology (from last century)

4More details in Storchak et al., PEPI 2015

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Major Sources of Phase Data:

1.Gutenberg Notepads (1904-1917) and BAAS (1913-1917), ISA (1904-1907)2.ISS Bulletins (1918-1963)

Instrumental Data from Printed Seismological Bulletins

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1960-19701918-19591904-1917

Body/Surface Wave

Amplitudes

Body Wave Arrival Times

Period

Quality station bulletinsDIGITALLY

AVAILABLE, ISC database

1971-2009

DIGITALLY NOT AVAILABLE BEFORE THIS PROJECT

DIGITALLY AVAILABLE, ISC

database

Pre-ISS: Gutenberg notepads, BAAS and ISA bulletins

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Gutenberg notepads, (pre-1913):

data digitized only for large earthquakes

BAAS bulletins, 1913-1917: data digitized for all earthquakes

ISA bulletins, 1904-1907: data digitized for all earthquakes

Processing ISS

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ISS is a primary source of phase data for earthquakes occurred before digital era. Scans of all ISS pages are available from SISMOS. OCR technique has bee applied to the scans…

ISS Collection, 1918-1963

Processing ISS

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Digitizing the ISS bulletins: status

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Years Status

1918-1942 Digitally available as FFB file, from the so-called “Shannon

tape”. Missing phase data for ~210 earthquakes currently

being digitized

1943-1959 Recently completed (more than 10000 pages edited) thanks

to the ISC-GEM catalogue extension work; digitally available

as FFB file

1960-1963 Digitally available via the ISC website (www.isc.ac.uk) after

the work by Villaseñor&Engdahl (2007)

ISS Station coverage, pre-1960

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Di Giacomo et al., PEPI 2015, modified …and counting!

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Amplitude Data Collection

~1,000,000~10,000

1960-19701918-19591900-1917

Body/Surface Wave

Amplitudes

Body Wave Arrival Times

Period

DIGITALLY AVAILABLE, ISC database

Quality station bulletins

1971-2009

DIGITALLY NOT AVAILABLE BEFORE THIS PROJECT

Adding amplitudes from historical

seismological bulletin

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1906 San Francisco

earthquake report from Göttingen

(Germany) station bulletin.

The same report stored in digital format in the ISC database. Period and amplitude data finally available for magnitude recomputation.

Stations contributing to magnitude re-computation, 1904-1963

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Location improvements

14More details in Bondár et al., PEPI 2015

Improvements in magnitude, especially Ms

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ISC-GEM recomputed Ms Ms from Abe’s catalogue

More details in Di Giacomo et al., PEPI 2015

Summary

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• In order to produce the ISC-GEM catalogue, we digitized a multitude of sources of parametric seismological data to facilitate location and magnitude re-computation for earthquakes that occurred before the beginning of the digital era

• The parametric data collected (and being collected pre-1960) in this project will be useful for any future study for earthquakes occurred before station data was digitally available

• Scans of the processed bulletins are available in PDF at SISMOS website: http://storing.rm.ingv.it/bulletins/ISC-GEM/

Di Giacomo et al., PEPI 2015

…and counting!