The dynamic effect is a very important issue widely debated by scholars when studying the genetic and disaster-causing mechanisms of earthquake-triggered landslides.First,the dynamic effect mechanism and phenomena of ...The dynamic effect is a very important issue widely debated by scholars when studying the genetic and disaster-causing mechanisms of earthquake-triggered landslides.First,the dynamic effect mechanism and phenomena of earthquake-triggered landslides were summarized in this paper.Then,the primary types of dynamic effects were further used to interpret the Mogangling landslide in Moxi Town of Luding County,China.A field investigation,remote sensing,numerical calculation and theoretical analysis were carried out to illustrate the failure mechanism of slope rock masses affected by earthquakes.The interaction between seismic waves and slope rock masses and the induced dynamic effect of slope rock masses were primarily accounted for in the analysis.The slope topography,rock mass weathering and unloading characteristics,river erosion,regional seismogenic structure,and rock mass structure characteristics were also discussed.The results showed that the formation of the Mogangling landslide was mainly related to the high amplification effect of seismic acceleration and back slope effects,interface dynamic stress effects,and double-sided slope effects of seismic waves caused by the catastrophic Ms 7.75 Moxi Earthquake in 1786.The principles for the site and route selection of large-scale infrastructure in the planning stage and the scientific prevention of seismic geological disasters were proposed on the basis of the dynamic effect of earthquake-induced landslides.展开更多
A geologic time scale is a chronological system that separates the geological strata of a planetary body into different units in temporal sequence and shows its progressive evolution.The time scale of the Moon was est...A geologic time scale is a chronological system that separates the geological strata of a planetary body into different units in temporal sequence and shows its progressive evolution.The time scale of the Moon was established a half-century ago during the telescopic-early Apollo exploration era,using data with limited spatial coverage and resolution.The past decades have seen a wide array of studies,which have significantly extended our understanding of global lunar geologic evolution.Based on a comprehensive review of lunar evolution with respect to the dynamical changes,we propose two major updates to the current lunar time scale paradigm to include the evolution of both endogenic and exogenic dynamic forces now known to have influenced early lunar history.Firstly,based on the temporal interplay of exogenic and endogenic processes in altering the Moon,we defined three Eon/Eonothem-level units to represent three dynamical evolutionary phases.Secondly,the pre-Nectarian System is redefined and divided as the magma ocean-era Magma-oceanian System and the following Aitkenian System beginning with the South Pole-Aitken basin.The ejecta of this basin,Das Formation,was deposited on the primordial lunar crust as the oldest stratum produced from exogenic processes.The updated lunar time scale,facilitated by the post-Apollo exploration and research advances,provides an integrated framework to depict the evolution of the Moon and has important implications for the geologic study of other terrestrial planets.展开更多
基金supported by the China Geological Survey Projects(Nos.20160272,20211379)the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0904)。
文摘The dynamic effect is a very important issue widely debated by scholars when studying the genetic and disaster-causing mechanisms of earthquake-triggered landslides.First,the dynamic effect mechanism and phenomena of earthquake-triggered landslides were summarized in this paper.Then,the primary types of dynamic effects were further used to interpret the Mogangling landslide in Moxi Town of Luding County,China.A field investigation,remote sensing,numerical calculation and theoretical analysis were carried out to illustrate the failure mechanism of slope rock masses affected by earthquakes.The interaction between seismic waves and slope rock masses and the induced dynamic effect of slope rock masses were primarily accounted for in the analysis.The slope topography,rock mass weathering and unloading characteristics,river erosion,regional seismogenic structure,and rock mass structure characteristics were also discussed.The results showed that the formation of the Mogangling landslide was mainly related to the high amplification effect of seismic acceleration and back slope effects,interface dynamic stress effects,and double-sided slope effects of seismic waves caused by the catastrophic Ms 7.75 Moxi Earthquake in 1786.The principles for the site and route selection of large-scale infrastructure in the planning stage and the scientific prevention of seismic geological disasters were proposed on the basis of the dynamic effect of earthquake-induced landslides.
基金This work was supported partly by the National Key Research and Development Program of China(Grant No.2022YFF0503100)the B-type Strategic Priority Program of the Chinese Academy of Sciences(Grant No.XDB41000000)+1 种基金the National Natural Science Foundation of China(Grant Nos.41902317,41941002,41773065)the National Science and Technology Infrastructure Work Projects(Grant No.2015FY210500).
文摘A geologic time scale is a chronological system that separates the geological strata of a planetary body into different units in temporal sequence and shows its progressive evolution.The time scale of the Moon was established a half-century ago during the telescopic-early Apollo exploration era,using data with limited spatial coverage and resolution.The past decades have seen a wide array of studies,which have significantly extended our understanding of global lunar geologic evolution.Based on a comprehensive review of lunar evolution with respect to the dynamical changes,we propose two major updates to the current lunar time scale paradigm to include the evolution of both endogenic and exogenic dynamic forces now known to have influenced early lunar history.Firstly,based on the temporal interplay of exogenic and endogenic processes in altering the Moon,we defined three Eon/Eonothem-level units to represent three dynamical evolutionary phases.Secondly,the pre-Nectarian System is redefined and divided as the magma ocean-era Magma-oceanian System and the following Aitkenian System beginning with the South Pole-Aitken basin.The ejecta of this basin,Das Formation,was deposited on the primordial lunar crust as the oldest stratum produced from exogenic processes.The updated lunar time scale,facilitated by the post-Apollo exploration and research advances,provides an integrated framework to depict the evolution of the Moon and has important implications for the geologic study of other terrestrial planets.
