It is well known that China has suffered more human fata1ities from natural disasters than any other nation in the world. In the mountain areas especially, the impacts of landslides and debris flows on developmentare great and apparently growing. They destroy or damage residential and industrial development, agricultural and forest lands, highways and railways.
The Institute of Mountain Hazards and Environment (IMHE) is one of the institutions under the Chinese Academy of Sciences and the Ministry of Water Conservancy. Since the 1960s， considerable effort has gone into the reduction of mountain hazards and rehabi1itation of degraded mountain environments. Significant advances have been made by the IMHE in respect to the studies of mountain hazards and environment during the last decade. In addition to the ωpics of hazard analysis, environment assessment ， approaches to reduce hazards, the application of new techniques, such as remote sensing. monitoring and warning system, laboratory simulation and modeling studied has also been performed by the IMHE. These notable developments have added new dimensions to the hazards and environment sciences and enhanced its academic status and practical significance to China.

This book is a collection of papers, which tries to highlight some of the major aspects of the research progress in the IMHE in the last decade. It should not be regarded as comprehensive one. Obviously,the size of this volume does not allow it to include all issuse related to mountain hazards and environment.

In editing this volume ，the authors' manuscripts have been retained without substantial alteration and only slight refinement of English. The viewpoits in the papers are those of the authors. Also，the editors have not added any supplement to some papers which are apparently somewhat incomplete in coverage. Given the limits of our English knowledge and experience, it is inevitable that some errors may have crept into this book. We , therefore, welcome all critical comments.

It is hoped that this book will provide a basis for the understanding of recent  evelopments in the study of Chinese

mountain hazards and environment which had not been sufficiently known by foreign scientists interestted in these subjects and hence , promote more fruitful exchanges of both scholars and information between the IMHE and similar foreign institutions. The editors and authors gratefully acknowledge the assistance they have received from the Directors of the IMHE and many other interested individuals.