GEOLOGICAL CONDITIONS IX RELATION TO EARTHQUAKE. iqo, 



7. The Kyaukkyan fault, which shows at the surface as a great 

 scarp forming a conspicuous feature of the landscape, as seen 

 from the railway between May my o and Hsum-hsai. It closes up 

 the view towards the east, rising like a wall beyond the broad 

 valley of the Kelaung and Hpawng-aw streams, surmounted by 

 precipitous cliffs of limestone. 



At the point where it is crossed by the railway it takes 

 the form of a uniclinal flexure in the limestone, rather than a 

 fault scarp, and the ascent from the valley is only about 400 

 feet, but there is a distinct fault along the crest, with a down- 

 throw towards the west. Further north the line of dislocation 

 is not easilv perceived, but it probably continues some distance 

 further into the Chaung Magvi and Mica Schist series than is 

 shown on the map. For a few miles the Xam-pan-hse stream flows 

 along it. and in this region the down-throw is on the eastern 

 sidef "Further to the south the crest remains perfectly level 

 backed by a plateau rising very gradually towards the edge of 

 the Gokteik gorge, but the flexure increases in importance, while 

 at the same time the fault itself appears as a line of vertical cliffs 

 just below the crest, until the differential movement becomes 

 so great that the older Palaeozoic rocks beneath the limestone 

 are exposed along the face of the scarp, which by this time 

 has reached a height relative to the plateau below, of some 3,000 

 feet. Along the base the edges of the Plateau Limestone are 

 seen inclined at a high angle or even vertical, but the strata 

 arc quickly bent into an almost horizontal position, and between 

 the base of the scarp and Wetwin are found everywhere with a 

 moderate inclination towards the east. ' (*) 



South of Lat, 22°, the direction and throw of this great dis- 

 placement are unknown, but it is thought that it continues for 

 some considerable distance. 



The origin of these vertical subsidences is obscure. La Touche 

 has pointed out that m the manner in which they are represented 

 at times bv a monoclinal flexure, they recall the vertical fault 

 systems of the Colorado plateau described by Gilbert and Dutton,( 2 ) 

 and that they are apparently due to local and deep-seated subsidences 



i La Touohes Loc cit., p. 863. 



2 Geology of portions of Nevada, Oto, U. S. Oeol. Surveys ; M .of 100° Meridian. 

 Vol. III. pp. 48-57. Sec also Geology of the High Plateaus of Utah. U. S. Oeol. 

 Surveys, 1880, pp. 25-54. 



