Report on the 18th International Symposium on Geo-disaster Reduction and the 4th Gu Dezhen Lecture, 20–22 November 2020, Beijing, China

The 18th International Symposium on Geo-disaster Reduction (ISGdR) was held on 20–22 November in Beijing, China, focusing on the theme of “Improving the Relationship between Geoenvironment and Society”. In this symposium, a high-level Gu Dezhen Lecture and a number of keynote and invited lectures provided a platform for scientists, industrial professionals and students to share their researches and exchange novel ideas on geo-disaster reduction in a hybrid way of offline and online.

The 18th International Symposium on Geo-disaster Reduction (ISGdR) and the 4th Gu Dezhen Lecture were focusing on the theme of "Improving the relationship between Geoenvironment and Society" and attracted more than 90 scientists and engineers offline and online from 9 countries to give 31 high-level academic presentations on the topics of geo-disasters. Besides, the livestream channel of this symposium attracted approximate 900,000 click volume. Honourably, Prof. Jianbing Peng, an Academician of CAS, was invited as the 4th Gu Dezhen Lecturer and presented a speech on research of loess. Besides, there were seven academic sessions including the Keynote Lectures and Invited Lectures. In addition, a pre-event on annual Board of Representative Meeting of ICGdR was organized as well.

Opening ceremony
Prof. Shengwen Qi, Co-chair of the organizing committee, hosted the opening ceremony and declared the symposium open on behalf of the organizer, IGGCAS. In addition, five speeches were presented as the prelude (see Fig. 1). Dr. Xiaonan Duan delivered a welcome speech to all the distinguished scholars and experts from all over the world as a representative of CAS. Prof. Jiyang Wang, an academician of CAS, introduced academic stories of Prof.
Gu Dezhen who was one of most well-known geologists in China. Besides, Prof. Huiming Tang (Vice Director of ENGEO) and Prof. Qingyun Di (Vice Director of IGGC AS) expressed great support and best wishes to the important events. Finally, Prof. Fawu Wang, present of ICGdR expressed his appreciation to the organizing committee and introduced the development of ICGdR, including its mission, structure, member organizations, history with exciting activity albums and so on. The opening ceremony ended up with a group photo as shown in Fig. 2.

Certificate and award ceremony
Following the open ceremony, Prof. Fawu Wang hosted the certificate and award ceremony and presented certificates to part of the participants who attended the opening ceremony offline. At the beginning, Prof. Wang introduced five new ICGdR memberships and presented the certificates to them (Fig. 3a). They are Prof Shuheng Sun (Liaoning Investigation Institute of Hydrogeology and Engineering Geology), Prof. Jianhong Ye (Institute of Soil and Rock Mechanics, CAS), Prof. Wanghua Sui (IMWA China National Commission), Prof. Yonggui Chen (Tongji University) and Prof Hu Zheng (Tongji University). Besides, the 2019 Best Paper Award of ICGdR official journal Geoenvironmental Disasters was shared by two papers. They are "Spatial and temporal appraisal of drought jeopardy over the Gangetic West Bengal, eastern India" by Krishna Gopal Ghosh and "Three-dimensional seismic slope stability assessment with the application of Scoops3D and GIS: a case study in Atsuma, Hokkaido" by Shuai Zhang and Fawu Wang. Two cheques worth of 600 Euro were awarded to the authors' representative (Fig. 3b). In addition, President Wang presented the Science Achievement Awards to Prof Sabatino Cuomo and Prof. Hengxing Lan (Fig. 3c). The Outstanding Activity Awards were presented to Isakbek Torgoev (Institute of Geomechanics

Keynote lectures
The Keynote Lectures included 13 presentations mixed with 17 invited lectures in seven sessions. The details, including topic titles, presenters (see Figs. 5, 6 and 7) and affiliations, were summarized in Table 1.
The lectures covered various topics related to the theme of this symposium, including mechanism analysis of geohazards, investigation methods, socio-economic effects and so on.

Closing ceremony
Followed the last keynote presentation on 22 November, the closing ceremony was hosted by Prof. Fawu Wang on behalf of ICGdR. He gave a closing speech and expressed sincere appreciation to the organizer and coorganizers for this special symposium during the worldwide COVID-19 pandemic period.