Characteristics and triggering mechanism of Xinmo landslide on 24 June 2017 in Sichuan, China

At 5: 39 AM on 24 June 2017, a huge landslide-debris avalanche occurred on Fugui Mountain at Xinmo village, Diexi town, Maoxian county, Sichuan province, China. The debris blocked the Songpinggou River for about 2 km, resulting in a heavy loss of both human lives and properties(10 deaths, 3 injuries, 73 missing, and 103 houses completely destroyed). The objectives of this paper are to understand the overall process and triggering factors of this landslide and to explore the affecting factors for its long term evolution before failure. Post event surveys were carried out the day after the landslide occurrence. Information was gathered from literature and on-site investigation and measurement. Topography, landforms, lithology, geological setting, earthquake history, meteorological and hydrological data of the area were analysed. Aerial photographs and other remote sensing information were used for evaluation and discussion. Eye witnesses also provided a lot of helpful information for us to understand the process of initiation, development and deposition. The depositional characteristics of the moving material as well as the traces of the movement,the structural features of the main scarp and the seismic waves induced by the slide are presented and discussed in detail in this paper. The results show that the mechanism of the landslide is a sudden rupture of the main block caused by the instability of a secondary block at a higher position. After the initiation, the failed rock mass at higher position overloaded the main block at the lower elevation and collapsed in tandem. Fragmentation of the rock mass occurred later, thus forming a debris avalanche with high mobility. This landslide case indicates that such seismic events could influence geological hazards for over 80 years and this study provides reference to the long term susceptibility and risk assessment of secondary geological hazards from earthquake.

Information Entropy of Palaeocommunity in Geological History

As an ecosystem in geological history, palaeocommunity has the essence of thermodynamics. This paper introduces the concept of entropy into the study of the evolution of palaeo-community, and proposes four parameters to represent the structure feature of palaeo-community. This theory is used to calculate the evolution mode of branchipod community of Maokou formation in Liziya area, Huaying Moumtain, Sichuan.

Mass Loss from Glaciers in the Chinese Altai Mountains between 1959 and 2008 Revealed Based on Historical Maps, SRTM, and ASTER Images

Mass loss of glaciers in the Chinese Altai was detected using geodetic methods based on topographical maps(1959), the Shuttle Radar Topography Mission(SRTM) Digital Elevation Model(DEM)(2000), and the Advanced Space-borne Thermal Emission and Reflection Radiometer(ASTER) stereo images(2008). The results indicate that a continued and accelerating shrinkage has occurred in the Chinese Altai Mountains during the last 50 years, with mass deficits of 0.43 ± 0.02 and0.54 ± 0.13 m a-1 water equivalent(w.e.) during the periods 1959-1999 and 1999-2008, respectively.Overall, the Chinese Altai Mountains have lost 7.06 ±0.44 km3 in ice volume(equivalent to-0.43 ± 0.03 m a-1 w.e.) from 1959-2008. The spatial heterogeneity in mass loss was potentially affected by comprehensive changes in temperature and precipitation, and had a substantial correlation withglacier size and topographic settings. Comparison shows that in the Chinese Altai Mountains glaciers have experienced a more rapid mass loss than those in the Tianshan and northwestern Tibetan Plateau(TP), and the mass balance of glaciers was slightly less negative relative to those in the Russian Altai, Himalaya, and southern TP.

全球化进程中的克什克腾:打造世界地质公园的空间特殊性

克什克腾世界地质公园作为空间连通性与整体性的一个矛盾结合点存在着。区划面积5000平方公里,保护区面积1 750平方公里,包含享有不多的共同地质历史的多个区域。从休眠火山壁崖到花岗石臼,再到沙丘,这些"地貌"的特点就如同一个统一的国家由不同民族构成。它们融合在一起,又有明显的各自特征,提供了许多关于如何对地区进行分类和概念化的知识。

Genetic differentiation in two widespread, open-forest bird species of Southeast Asia （Copsychus saularis and Megalaima haemacephala）： Insights from ecological niche modeling

Ecological niche modeling has emerged as an useful tool in the investigation of the phylogeographic histories of species or communities in a region. The high biodiversity （oftentimes cryptic）, and complex geography and geological history of Southeast Asia particularly call for multipronged approaches in phylogeographic investigations. Past studies have focused on taxa that are associated with lowland rainforests, which is the dominant natural vegetation type. Here, we combine published phylogenetic data, ecological niche modeling and paleo-climate models to reveal potential drivers of divergence in two open-forest bird species, the oriental magpie-robin Copsychus saularis and Coppersmith barbet Megalaima haemacephala. In spite of broad overlap in current distributions, there are subtle differences in their climatic niches, which result in different responses to past climatic changes. For C saularis, both Last Glacial Maximum climate models indicated that the entire Sundaland was climati- cally suitable, while phylogenetic analyses found divergent eastern and western Sundaland lineages. We thus postulate that this genetic divergence was a result of past separations of coastal habitats into eastern and western portions due to the emergence of Sunda shelf as sea-level fell. The current separation of morphological subspecies in Borneo is maintained by low climatic suitability （high annual rainfall） in certain regions. The extirpation of M. haemacephala from Borneo and southern Malay Peninsula might have been driven by unsuitable conditions （high temperature seasonality） in central Sundaland and/or the lack of open woodlands. Our study shows that ecological niche modeling adds a powerful dimension to our attempt to understand lineage evolution in space [Current Zoology 61 （5）： 922-934, 2015].