The natural gas hydrates-bearing shaly silt reservoirs are considered to be the most difficult target in exploitation. The first trial production test of the gas hydrate in the South China Sea conducted in 2017 proved that the reservoir is exploitable. On the basis of the understanding of the previous trial production, optimization and fine description of hydrate deposits, numerical simulation and onshore tests, the second gas hydrate trial production test were carried out by the China Geological Survey in the Shenhu sea area of the South China Sea from October 2019 to April 2020. This trial production overcame a series of technical problems, such as well head stability, horizontal well drilling, reservoir stimulating and sand controlling and accurate depressurizing, and achieved continuous gas production for 30 days, with a total gas output of 861400 cubic meters and a daily average gas production of 28700 cubic meters, which is 5.57 times the first trial production, thus greatly increasing the daily gas production and total gas production. The results show that there existed no abnormal methane content in sea floor, sea water and atmosphere during the whole process. The success of this test shows that it is possible to efficiently and safely develop the gas hydrate in shaly silt reservoirs.

With the rapid development of new energy vehicles, lithium as an energy metal is increasingly important in recent years. This paper briefly summarizes the progress of the lithium prospecting both in China and abroad between 2015 and 2016 and the development trend. The authors focus on the progress and prospecting of brine type, hard rock type and other types of lithium ore as well as the hot lithium prospecting areas in the world. Meanwhile, combined with the development of new industry and lithium resources utilization, some suggestions are made on prospecting and exploration of lithium resources in China. People should further understand lithium resources in China and strengthen the prospecting work in key areas so as to provide resources for the construction of large-scale lithium resources base. Geologists should not only focus on the brine type and hard rock type lithium mines but also pay attention to the prospecting for new types of lithium ore so as to improve resource utilization efficiency and promote the transformation and upgrading of related industries. Scientists should begin to study the recycling of lithium and the highend exploitation and utilization of lithium as an energy metal for occupying the technical key point to provide a scientific basis.

In recent years, a typical type of catastrophic ridge-top (or high-position) rockslide often occur in the strong earthquakes such as the Wenchuan earthquake. It exits out from the upper part of the steep slope and forms a volley fall with impact and crushing effect and dynamic erosion effect, causing the slide body to disintegrate and fragment, which transforms into rapid and long run-out avalanche debris or debris flow, and entraining the lower part of rock and soil mass, so that the volume increased significantly. The Xinmo landslide is this typical, it occurred at Maoxian County, Sichuan Province on June 24, 2017. The elevation of the crown of the Xinmo landslide was about 3450 m and the front edge was about 2250m. The height difference of landslide was 1200m, and the horizontal distance was about 2800 m. Its volume was up to 16.37 million m³. The landslide buried the Xinmo Village, leading to the death of 83 people. The Xinmo landslide was located on the western wing of the Jiaochang arc-shaped tectonics. Its parent rocks were the medium to thick layered metamorphic sandstone intercalated with slate in the Middle Triassic. The region was not only the epicenter area of the Diexi earthquake with magnitude 7.5 in 1933 (the intensity of the earthquake was X) but also the strong earthquake-affected area of the Wenchuan Ms8.0 earthquake in 2008 (the intensity was IX). The mountains, especially the ridge-top rockmass, were fractured/cracked due to the strong earthquakes. There were multiple groups of discontinuous structural planes in the sliding source zone, and hence the thick blocky rock mass was cracked into fragmented blocks, and the bugling area was formed at the elevation varying from 3150 to 3450 meter. In particular, there were two sets of anti-dip large joints in the sliding source area, indicating a typical failure mechanism "locked-section". Rockslide with a volume of 3.9 million m³ exited and continuously accumulated at the back of previous residual landslide. The "overload effect" triggered the slope instability under the exit and transferred into long runout channeled avalanche debris. Because the terrain was wide and the slope angle gradually decreased, avalanche debris converted to diffused one and then to scattered accumulation. The Xinmo landslide presents a typical disaster mode of the rapid and long runout initialed due to rockslide at ridge-top in strong earthquake area. A new method should be established to recognize this type of landslides. Wherever there are large-scale rockslides in steep ridge-top region, the "dynamic erosion effect" and the "overloading effect" on the previous accumulation and the talus of slope due to impact processes should be considered. Especially in the place where there is abundant groundwater along the gully, the possibility of a rapid and long runout rockslide-avalanche debris will increase. Therefore, in conducting the investigation of geological disaster, the town, village or other populated areas should be zoned as risk area on the previous landslide accumulation of slope below the exit of the rockslide at the ridge-top. The authors emphasize that, in the strong earthquake mountainous regions, the static balance method for the landslide stability should be considered, and the dynamic research on the landslide runout processes and the disaster mode should be strengthened.