1Q4 OOGGIN BROWN : THE BURMA EARTHQUAKES OF MAY 1012. 



CHAPTER V. 



GEOLOGICAL CONDITIONS IN RELATION TO THE EARTH- 

 QUAKE. 



In his account of the Kangra earthquake, Mr. C. S. Middle- 

 miss has shown how Important the study of 

 Importance of such Hie Keologioal structure of the shaken area 

 may be^ 1 ) TJiis is primarily OH account of the 

 generally accepted theory that great earthquakes are due to 

 strains set up in the earth's crust by geoteotonio movements, 

 and to their sudden relief by Blipping along a fault. Yet an- 

 other aspect of the subject is to be found in the superficial and 

 secondary effects of the earthquake, consequent upon the nature 

 and disposition of the rocks at the surface. 



It has already been shown that the great Kyaukkyan fault 

 was probably in some way connected with the shock, and in the 

 following pages it is proposed to discuss the geological structure 

 of the country more especially from the tectonic point of view, 

 and to adduce the remaining evidence in support of this view. 

 The interpretation of the geological structure of the Northern 

 , Shan States is mainly due to the researches of 



Structural Geology oi ._ _ * 



(ho affeoted portions Mr. I^a louche, though other contributions have 



of the Northern Shan been made by earlier workers. The account 



which follows here is based almost entirely 



upon the work of the former geologist, from whom 1 had the 



good fortune to learn my early lessons in Indo-Chinese geology. 



The severely shaken area lies partly in the Northern Shan States, 



thellluby Mines. Mandalay and Kyaukse districts and partly in 



the Southern Shan States. By far the greater portion is comprised 



within the " plateau " of the Shan States. Other portions form part 



of the plains of the Jrrawaddy basin which is filled up with strata 



of Tertiary age and alluvium, and from which the hills at the 



western edge of the plateau-like country rise boldly in an 



unbroken wall of jungle covered scarps, extending far to the north 



and s<uith, and reaching in the neighbourhood of Maymyo, that 



is in a distance of some lo miles as the crow flies, an ele- 



1 '. S. Middlomiss : Preliminary Account of the Kangra Earthquake of ltli 

 April 1905. flee, Geol. &urv., Intl. Vol XXX!!. !'t. 1, p. 281, 



