Beno Gutenberg. Photo ID 1.15.1-13
|In the News
Collating earthquake data
Professor Hiroo Kanamori has deposited in the Caltech Archives four volumes of the International Seismological Summary (ISS) for the years 1931-1934. All are closely annotated in Gutenberg's hand. These new volumes join others in the Gutenberg papers which date between 1918 and 1942 with gaps, one of which is now bridged.
Gutenberg systematically annotated the ISS over many years. These annotations form a companion piece to a separate and extensive set of earthquake data which Gutenberg painstakingly made on tear-off note pads and which, like the ISS data, he revisited and reworked over time. The ISS bulletins and the data pads may or may not overlap each other for a given event. The two sets of data must be understood to be complementary, and together they provide a full picture of Gutenberg's meticulous working method.
A page from the 1931 ISS shows reported data from two events on August 15. The first event, centered in the mountains of Pakistan north of Jalalabad according to the coordinates given, occurred at 4:01:04 UT. The first station to record the shock was Andijan (Uzbekistan). The second event, in the Pacific Ocean off the coast of Japan, occurred at 12:43:48 UT. Both are annotated "deep" and are assigned a magnitude in red pencil "M=6±
and M=5 ¾", respectively. The magnitude figure helps to date the annotations, as Charles Richter's paper on the magnitude scale appeared in print in 1935. According to Professor Kanamori, the annotations were probably made in the 1940s.
Corresponding pages for both events on the ISS page may be compared with Gutenberg's note pads. –SE
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