This project will investigate the structural and earthquake rupture characteristics of transtensional faulting in Yunnan Province, China and will compare and contrast the characteristics of faulting in Yunnan with extensional faulting in the Basin- Range qnd Rocky Mountain Provinces of the United States. The work will be done in conjunction with Chinese collegues from the Geological Institute of the State Seismological Bureau, Beijing, China. The bjectives of this research are (1) to establish a regional kinematic model of tectonics in the Jinchuan--Eryuan extensional zone, (2) construct structural-mechanical models of selected fault zones, (3) interpret these models in terms of seismogenic rupture characteristics, and (4) compare the predicted behavior with that observed in the historical and paleo-seismological record. The work in Yunnan will be integrated wtih similar studies of active fault zones in the Basin-Range and Rocky Moutain regions of the western U.S. in an effort to further understanding of the relations between geologic structure and crustal seismogenics in general.