JAPANESE EARTHQUAKES — HECK 



205 



sons to make reports, (2) of a statistically minded government, and 

 (3) , in recent years, of an extensive network of seismographs. Guten- 

 berg, 6 after careful investigation, has reached the conclusion that the 

 main Japanese islands and adjacent seismically active sea bottom are 

 probably no more seismic than some other areas of equal extent, but 



Figure 3.— Map of epicenters, Japan to Kamchatka. (Courtesy Geological Society 



of America.) 



he considers that the seismicity of certain local areas in Japan reaches 

 a peak rarely, if ever, exceeded elsewhere. In Japan there have been 

 examples of every kind of earthquake except one— that occurring at 

 times in eastern North America, felt over a vast area but usually at 

 only moderate maximum intensity. 



GEOGRAPHICAL DISTRIBUTION 



Distribution according to depth. — This is so complex that the fol- 

 lowing statement, based on Gutenberg (see footnote 6) and figure 3, 



• B. Gutenberg and C. F. Richter, Seismicity of the earth, Geol. Soc. Amer., Spec Pap , 

 No. 34, 1941. 



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