Report on the 21st International Symposium on Geo-disaster reduction, 5–8 August 2023, Shanghai, China

The joint event of 21st International Symposium on Geo-disaster Reduction (21st ISGdR) was held onsite and online during 5–8 August 2023 in Shanghai, China. This symposium focused on the theme of “A new era for safe and resilient coastal and marine systems”, providing a platform for academics, researchers and practitioners from different countries to discuss the research progress and exchange ideas on the reduction of disasters. The symposium consisted of keynote lecture, invited lectures and other presentations in parallel session.


Introduction
In recent years, with the continuous development of marine resources, marine geological disasters have become more frequent.These disasters not only affect the construction of marine engineering projects but also pose risks to their safe operation, presenting new challenges to the development of marine system engineering.In order to enhance the exchange and discussion of key issues in the field of marine geo-disaster reduction, the 21st International Symposium on Geo-disaster Reduction was successfully held at Tongji University from 5-8 August 2023.
This conference serves as the annual academic meeting of the International Consortium on Geo-disaster Reduction (ICGdR) and was jointly organized by Tongji University and the UNESCO Chair on Earth Environment and Disaster Mitigation.The conference was held in a hybrid format, combining both online and offline sessions, and attracted significant attention from numerous experts and scholars worldwide.Over 80 representatives from 7 countries including China, the United States, Italy, Turkey, Japan, Nepal, and Malaysia, sharing and exchanging the latest research findings (Fig. 1).

Opening ceremony
The opening ceremony was chaired by Professor ZHENG Hu, the Secretary-General of the conference.The keynote speeches were delivered by Professor ZHU Hehua, an academician of the Chinese Academy of Engineering; Professor SHI Zhenming, Assistant President of Tongji University; Professor HUANG Yu, Head of the College of Civil Engineering at Tongji University; and Professor WANG Fawu, the President of the International Consortium on Geo-disaster Reduction (ICGdR).
Academician ZHU Hehua pointed out the frequent occurrence of marine disasters in recent years, posing potential threats to engineering construction, and emphasized the urgent need for international collaboration to explore new technologies for disaster prevention and reduction (Fig 2a).Professor SHI Zhenming expressed sincere gratitude and warm welcome to all the participants on behalf of the university, and briefly introduced the work conducted by Tongji University in the field of disaster prevention and reduction (Fig 2b Professor HUANG Yu expressed gratitude on behalf of the College of Civil Engineering and organizing committee, and expressed expectations for the conference to provide new ideas for marine disaster prevention and reduction.President WANG Fawu introduced the establishment of the International Consortium on Geo-disaster Reduction and expressed hope that the attendees would focus on cutting-edge research, actively engage in discussions, and make greater contributions to disaster prevention and reduction efforts. At the end of the opening ceremony, Prof. WANG Fawu hosted and presented ICGdR Award Ceremony.The winners of the ICGdR Award 2022~2023 and the Best Paper Award of Geoenvironmental Disasters 2022, the official journal of ICGdR, are listed in the table below (Tables 1 and 2).

Keynote lecture and parallel sessions
The conference featured 8 keynote presentations (Table 3) and over 40 special topic presentations, focusing on significant scientific issues and key technological approaches related to marine engineering construction and disaster prevention and reduction of geological hazards (Fig. 3).The Keynote Lecture of the 21 st ISGdR was chaired by Prof. ZHU Hehua and Prof. YE Weimin in the morning of 6 August, 2023, and Prof. LI Tonglu and Prof. JIA Yonggang in the afternoon of 7 August, 2023.The reports covered a wide range of topics, including analysis of submarine landslide disaster mechanisms, causes and characteristics of earthquake disasters, and AI-based risk assessment of marine geological hazards.

Closing ceremony
The closing ceremony of the conference was presided over by Professor LI Bo, the Secretary-General.The organizing committee presented certificates to the selected outstanding presenters (Fig. 4a), which is listed in Table 4.The host of the next conference introduced the preparation status of the upcoming event.Finally, Professor WANG Fawu, representing the organizing committee, delivered the closing remarks (Fig. 4b), expressing gratitude to the attendees and inviting them to continue participating in and supporting the activities of the consortium.
Through this symposium, scholars from both domestic and international backgrounds shared their latest research findings, engaged in extensive academic discussions, and put forward creative new ideas and approaches.The conference has sparked further global attention from numerous scholars regarding the issues of disaster prevention and reduction in marine geological hazards.It provided a systematic summary and

Post-Symposium field trip
Followed the onsite symposium, a field trip to the Dongtan Wetland in Pudong New Area, Shanghai, was conducted on the 8 August 2023 (Fig. 5).Dongtan Wetland is an important wetland conservation area.Situated in the southeastern part of Shanghai, adjacent to Hangzhou Bay, it is a naturally formed tidal flat wetland ecosystem.The total area of Dongtan Wetland is approximately 56.7 square kilometers, encompassing tidal flats, rivers, estuaries, salt pans, and sea areas, among other ecological environments.This trip focused on the engineering geology of estuarine and river mouth areas, as well as coastal zone engineering geology and conservation.

Fig. 1
Fig. 1 Group photo of participants of the 21st ISGdR

Fig. 3
Fig. 3 Keynote lecture: a keynote lecture presented by Academician HE Manchao; b keynote lecture presented by Professor Ranjan Kumar DAHAL; c keynote lecture presented by Professor Kwan Ben SIM; d keynote lecture presented by Professor Mandip SUBEDI; e keynote lecture presented by Dr. Beena AJMERA; f keynote lecture presented by Professor HUANG Yu; g keynote lecture presented by Professor Halil KUMSAR; h keynote lecture presented by Professor Sabatino CUOMO.

Fig. 4 Fig. 5
Fig. 4 Closing ceremony: a Photo of the best student presentation award ceremony; b Prof. WANG Fawu delivered the closing remarks on behalf of the organizing committee ).

Table 1
The Best Paper Award of Geoenvironmental Disasters

Table 2
The winners of the ICGdR Award 2022~2023

Table 3
List of the Keynote lectures

Table 4
The winners of the Best Student Presentation Award