1 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

Background The ISC and a Team of International Experts released in January 2013 the ISC-GEM catalogue ( ), 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. 2 or

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. 3 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) 4 More details in Storchak et al., PEPI 2015

5 Major Sources of Phase Data: 1. Gutenberg Notepads ( ) and BAAS ( ), ISA ( ) 2. ISS Bulletins ( ) Instrumental Data from Printed Seismological Bulletins 2)1) Body/Surface Wave Amplitudes Body Wave Arrival Times Period Quality station bulletins DIGITALLY AVAILABLE, ISC database DIGITALLY NOT AVAILABLE BEFORE THIS PROJECT DIGITALLY AVAILABLE, ISC database

Pre-ISS: Gutenberg notepads, BAAS and ISA bulletins 6 Gutenberg notepads, (pre-1913): data digitized only for large earthquakes BAAS bulletins, : data digitized for all earthquakes ISA bulletins, : data digitized for all earthquakes

Processing ISS 7 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,

Processing ISS 8

Digitizing the ISS bulletins: status 9 YearsStatus Digitally available as FFB file, from the so-called “Shannon tape”. Missing phase data for ~210 earthquakes currently being digitized Recently completed (more than pages edited) thanks to the ISC-GEM catalogue extension work; digitally available as FFB file Digitally available via the ISC website ( after the work by Villaseñor&Engdahl (2007)

ISS Station coverage, pre Di Giacomo et al., PEPI 2015, modified …and counting!

11 Amplitude Data Collection ~1,000,000~10, Body/Surface Wave Amplitudes Body Wave Arrival Times Period DIGITALLY AVAILABLE, ISC database Quality station bulletins DIGITALLY NOT AVAILABLE BEFORE THIS PROJECT

Adding amplitudes from historical seismological bulletin 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,

Location improvements 14 More details in Bondár et al., PEPI 2015

Improvements in magnitude, especially Ms 15 ISC-GEM recomputed MsMs from Abe’s catalogue More details in Di Giacomo et al., PEPI 2015

Summary 16 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: Di Giacomo et al., PEPI 2015 …and counting!