The 5th International Geo-hazards Research Symposium: In memory of Prof. Tsanyao Frank Yang (IGRS-2016) was held in Taipei, Taiwan, from October 17 to 20, 2016. This conference was a sequel, and the venue was confirmed during the 4th IGRS held at the NASA Ames Research Center in California, the USA, in December 2014. The conference was devoted to all aspects of research and development in Geo-hazards Science covering geo-hazards like earthquakes, tsunamis, landslides, floods, offshore geo-hazards and climate change. Geo-hazards could be of geological, hydrological or geo-morphological nature and threaten all mankind. Natural geo-hazards are the major cause of loss of life and property. The threat could only be addressed successfully through a multidisciplinary approach involving international or global participation. We worked on improving our scientific understanding of the nature and causes of such hazards and to work towards more reliable prediction of their occurrence and magnitude. This conference brought together the scientific advances in obtaining perception and response to the geo-hazards.

This meeting was represented by global participations, i.e., from USA, Italy, Germany, India, Japan, and China. The participants from different fields, i.e., geoscientists, (geologists, geophysicists, geochemists, geodesists, etc.) mathematicians, engineers, physicists and social scientists who are dedicated to multidisciplinary investigations on geo-hazards joined this conference. In total 86 abstracts were received and about 75 participants attended this conference and presented their research work. During the conference 4 Keynote speeches, 16 Invited talks, 31 Oral and 22 Poster presentations were delivered. Therefore, this is an opportune time to publish a special issue to illustrate some of the recent advances in geo-hazards and we are pleased to include a total of eleven peer-reviewed papers in this special issue from fifteen submitted research papers.

This thematic edition includes 11 papers covering a range of topics of geo-hazards and radiation hazards methodology, analyses and conclusions drawn from a rich body of research work in these studies presented at the 5th IGRS. Most of the accepted research papers cover the impact of radioactivity on the quality of human life and for health risk assessments. Some papers deal with the estimation of health risk due to the presence of radon, thoron and progeny in the environment of Indian Himalaya. In some of the studies, attempts have been made to see the effect of geology, geohydrology and different types of soil and groundwater sources on radon levels in Himalayan region. The editors thank all authors who have contributed to this thematic volume and are also grateful to all reviewers for providing critical and constructive comments/suggestions that improved the manuscripts. Without their efforts the publication of this special issue would not be possible. Special thanks are due to staff members of the editorial office of the journal, who spent much time and effort, carefully editing and improving all manuscripts in this volume.