The 19^th International Symposium on Geodynamics and Earth Tides was successfully held from June 23^rd to 26^th at the Innovation Academy for Precision Measurement Science and Technology (APM) of the Chinese Academy of Sciences. The mixed online/offline symposium lasted for 4 days. More than 300 experts, scholars and students participated in the in-person symposium, and 192 participated in the symposium online, including more than 100 foreign experts and scholars from 26 countries such as France, Germany, Italy, the United States, Japan, Belgium, Russia, India, Poland, Brazil and Argentina. An expert of Kyoto University, and domestic participants of the University of Chinese Academy of Sciences, Shanghai Astronomical Observatory of the Chinese Academy of Sciences, Wuhan University, China University of Geosciences, Huazhong University of Science and Technology, the National Institute of Metrology of China, the Second Monitoring and Application Center of China Earthquake Administration, the Institute of Earthquake Forecasting of China Earthquake Administration, participated the in-person symposium at different venues.

The International Symposium on Geodynamics and Earth Tides is one of the series of conferences under the International Association of Geodesy (IAG). Since it was first held in 1949, it has become one of the most important international conferences in the field of geodesy. The 19^th International Symposium on Geodynamics and Earth Tides is the second time of this series of conferences being held in China since 1993. This fully reflects China’s international status and important role in this research field. The topics of this symposium covered six thematic areas including solid earth's tidal and non-tidal loading effects, geodynamics and seismic cycles, earth rotation changes, time-varying gravity field and mass distribution, underground fluid monitoring, and new technology and software development.

Professor SUN Heping, academician of the Chinese Academy of Sciences, the directing board member of the International Geodynamics and Earth Tide Service (IGETS), and chairman of the Local Organizing Committee of the conference, presided over the symposium. He thanked experts and scholars from different regions of the world for participating in the symposium. He also expressed his gratitude to IAG for entrusting China with undertaking this important conference. LUO Zhiqiang, Dean of APM, delivered a welcome speech on behalf of the organizer, and briefly introduced the history, disciplines classification and other aspects of APM. Harald Schuh, Honorary Chairman of IAG, XU Houze, Academician of the Chinese Academy of Sciences and Chairman of the Conference Scientific Organizing Committee, and Carla Braitenberg, a well-known Italian geophysicist, Vice Chairman of the Conference Scientific Organizing Committee, delivered their speeches respectively.

A total of 4 experts gave invited reports, 31 experts gave special academic reports, and 50 experts presented academic posters. Experts and scholars shared the latest research progress and results at home and abroad in the six thematic areas of the conference. Professor Harald Schuh from the German Research Center for Geosciences introduced the research progress of space geodesy in geodynamics in the invited report. Professor Carla Braitenberg from the University of Trieste in Italy looked into the geophysical needs involved in future research on mass transport in the Earth system and Earth gravity satellite missions in the invited report. Academician SUN Heping introduced China’s high-precision gravity observation network and the latest progress in the field of gravitational tides and geodynamics in the invited report. Professor Séverine Rosat from the University of Strasbourg in France introduced the gravity detection results of dynamic phenomena in the earth's interior from the seismic cycle to the movement of the earth's core.

At this conference, three scientists who have made outstanding contributions in the field of solid earth tides were awarded the Paul Melchior Medal, which is the highest international honor in the research field of solid earth tides. Professor David Crossly from Saint Louis University in the United States, Professor Gerhard Jentzsch from Clausthal University of Technology in Germany, and Professor Walter Zürn from Karlsruhe Institute of Technology in Germany were awarded the Paul Melchior Medal.

This symposium provides a high-level international information exchange platform for Chinese experts, scholars and students. In the symposium, they have opportunities to discuss cutting-edge scientific issues and development trends with their international counterparts, display the latest research results in China, and jointly promote the development and application of modern geodesy. The symposium-based collections will be published in two international journals: Pure and Applied Geophysics and Geodesy and Geodynamics. This symposium was funded by the Chinese Academy of Sciences and the National Natural Science Foundation of China.