Dispersioni of surface waves along various paths to Uppsala, Sweden

Abstract

Group velocity dispersion data of surface waves along a certainpatii give information only about the average erustal eondition overwhich the surface waves travelled. But if we observe them at manystations along many patlis which cross each other over a wide area,there is a possibility to deduce regional dispersion characters in thisarea and to get some information about the regional erustal conditions.This possibility was proved in the previous investigations by the presentauthor at- Tokyo, Japan (Santo 1961 b).Therefore, it is desirable to accumulate group velocity dispersiondata along various paths over the earth, especially since long-periodseismographs have been inst-alled recently at many stations.For this purpose, the present author began to investigate dispersioncharacters of surface waves along various paths, about two hundredand fifty in ali, to Tsukuba, Japan, in 1958 (Santo 1960 a, b, 1961 a, b, c).The dispersion data of Love waves could be classifled into eleven groups.For these representative curves, Roman numerals from (I) to (XI) weregiven, more Continental in this order. The dispersive character ofBayleigli waves could be classifled into seven curves, for which Arabienumerals from (1) to (7) were given, also more continental in this order.Of course, if we could get the dispersion data along an infinite numberof paths, they must show continuous variation, for instance, from (1)to (7) for Eayleigh waves.