Making Non-Digitally-Recorded Seismograms Accessible Online for Studying Earthquakes - Historical Seismology: Interdisciplinary Studies of Past and Recent Earthquakes - page 410

Fig. 6 Sample seismograms recorded on photographic paper. See text for explanation
1906 San Francisco (California) earthquake at Paisley, Scotland. It is difficult to
digitize from such an image because of the small time resolution, but most seis-
mograms for the first decade of instrumental seismology were recorded by Milne
seismographs. The second seismogram in Fig. 6 shows the 8 August, 1946 Mona
Passage (Puerto Rico - Dominican Republic) earthquake recorded by the electro-
magnetic Galitzin seismograph at De Bilt, the Netherlands. The third seismogram
in Fig. 6 shows the 28 June, 1944 Mexico-Guatemala earthquake recorded by the
electromagnetic Benioff seismograph at the Weston Observatory, Massachusetts,