In 1984, he saw the first demonstration of space geodetic equipment such as GPS(Global Positioning System) receivers at NASA's base in Southern California. Although the US GPS was not yet used for earthquake monitoring at that time,

he was exposed to GPS for the first time, learned the earliest literature on GPS, expanded his knowledge, broadened his vision, and laid a solid foundation for future applications. In 1985, Gu Guohua returned from his studies,

and with the strong support of the relevant departments of the Earthquake Bureau, he participated in the research of earthquake prediction and database cleaning, and compiled a set of crustal deformation data processing software,

which strengthened the theoretical basis and improved the programming ability through practice, and laid the foundation for the smooth transition to GPS observation research.

In 1990, he received a rare opportunity to study GPS data processing technology in Switzerland as a senior visiting scholar. From 1996 to the beginning of 2001, Gu Guohua participated in the "Ninth Five-Year Plan" national major scientific project "China's Crustal Movement Observation Network",

which mainly focused on GPS technology and mainly aimed at earthquake prediction. He was responsible for and presided over the completion of the construction of the data center of the network engineering GPS project,

and actually presided over the design of the network GPS continuous observation reference station. Later, he also participated in a sub-project of the "973" earthquake prediction research project and began to study the prediction of earthquakes by using GPS observation of crustal movement.

When his own research work can contribute to the national strategic development, Professor Gu Guohua's scientific research happiness and satisfaction have also been greatly improved.

Unlock earthquake precursor deformation codes with GNSS technology

Professor Gu Guohua is a dreamer of natural science who aims high and cares about people's livelihood. The development of high-precision GNSS(global satellite navigation system, including China's Beidou,

the United States' GPS, Europe's Galileo and Russia's GLONASS) technology has become one of the modern advanced disaster relief tools, millimeter (mm) level precision positioning technology is also the contemporary millimeter (mm) level precision monitoring technology of crustal movement.

Crustal movement and earthquake precursor deformation are analyzed. Firstly, he used the method of horizontal displacement vector time series analysis to show the horizontal displacement of the crust more directly.

He proposed a reference frame of dislocation which is more suitable for the study of coseismic displacement in huge earthquakes. After long-term research work, he formed a set of practical GNSS data analysis methods, data processing and mapping software for earthquake prediction research, and put forward relatively systematic and distinct academic views.

Before the magnitude 8 Wenchuan earthquake, Professor Gu Guohua started to study earthquake prediction with GNSS. The "China Crustal Movement Observation Network" is an observation project funded by the state after the Tangshan earthquake,

with earthquake prediction as its main purpose. The magnitude 8 Wenchuan earthquake occurred in the central and northern seismic belt in the regional network of 1000 GPS observation stations in the China Crustal Movement Observation Network,

along which a considerable number of observation stations are set up. Before the Wenchuan earthquake, the regional network made four observations in 1999, 2001, 2004 and 2007 respectively, and recorded the relevant data,

which also provided extremely rich data for the crustal movement before the earthquake. Although the complete regional network observation results were obtained only after the Wenchuan earthquake,

the horizontal and vertical displacement information, especially the precursory horizontal displacement and horizontal strain information with distinctive characteristics, were obtained before the Wenchuan earthquake.

The co-seismic horizontal displacements of these stations were obtained after the earthquake, and the co-seismic horizontal displacements of this major earthquake were the elastic recoil of the horizontal displacements of these stations accumulated before the earthquake,

that is, the horizontal displacements generated during the earthquake reversed the displacement of the observation stations, and the observation stations returned to the position before the earthquake to a considerable extent,

which was an obvious reaction between pre-earthquake action and earthquake time. The results show that precursory horizontal displacement exists in large earthquakes. After the Wenchuan earthquake in early 2009,

Professor Gu Guohua used the data of four GPS continuous observation stations near the Wenchuan earthquake epicenter to calculate the single period solution of the 30s sampling rate with BERNESE software.