基于2011年第一次全国水利普查成果、2018—2023年全国水土流失动态监测成果及2023年植被数据,分析山东省2011—2023年水土流失变化特征,结果表明:①2011—2023年,山东省水土流失面积、强度实现了“双下降”,水土流失面积减少了5287.37 ...基于2011年第一次全国水利普查成果、2018—2023年全国水土流失动态监测成果及2023年植被数据,分析山东省2011—2023年水土流失变化特征,结果表明:①2011—2023年,山东省水土流失面积、强度实现了“双下降”,水土流失面积减少了5287.37 km 2,降幅达19.40%;全省水土流失以轻度为主,其面积占全省水土流失面积的54.77%~94.94%;全省水土保持率呈持续增长趋势,2023年较2011年增加了3.34个百分点。②2020—2023年山东省水土流失面积和强度“双下降”态势比2011—2023年的更好,水土保持工作呈高质量快速发展的趋势。③2020—2023年耕地、林地、建设用地是全省水土流失的主要源地,其水土流失面积占全省水土流失面积的88%以上,是水土流失重点防治和关注区域。④2020—2023年,山东省坡耕地绝大部分水土流失发生在坡度≤15°耕地,在水土保持规划中应重点关注,同时应加大对坡度≤2°耕地的水土流失治理力度。⑤2020—2023年山东省水土流失相对集中分布在鲁中南低山丘陵土壤保持区和胶东半岛丘陵蓄水保土区,两区水土流失面积占全省水土流失面积的94%左右,是水土流失重点关注区域,尤其应加大对鲁中南低山丘陵土壤保持区的水土保持工作力度。分析了山东省水土流失变化的原因,提出了水土流失综合防治对策。展开更多
Long-period free oscillations provide robust information for the spatio-temporal characteristics of large earthquakes.In this study,we employ a normal-mode summation algorithm to generate threecomponent seismograms wi...Long-period free oscillations provide robust information for the spatio-temporal characteristics of large earthquakes.In this study,we employ a normal-mode summation algorithm to generate threecomponent seismograms within an aspherical,anelastic,and rotating Earth model,focusing on the excitation of seismic normal modes by the 2011 Tohoku megathrust earthquake.Specifically,we analyze the effects of seismic source parameters,including fault geometry,focal depth,and rupture duration.By comparing synthetic free oscillation spectra with observed data,we validate several source mechanisms and emphasize the need for horizontal observations to improve seismic mechanism inversions.Our quantitative analyses reveal that among fault geometry parameters,dip and slip angles have a more pronounced impact on excitation amplitudes than fault strikes.Certain fault configurations enhance the detectability of specific modes,underscoring the relationship between fault geometry and mode excitation.Normal modes also exhibit varying sensitivity to focal depth,with significant excitation amplitude changes at discontinuity boundaries.Additionally,we demonstrate that while rupture duration can be inferred by minimizing differences between observed and synthetic spectra,more extensive records and modes should be included.展开更多
文摘基于2011年第一次全国水利普查成果、2018—2023年全国水土流失动态监测成果及2023年植被数据,分析山东省2011—2023年水土流失变化特征,结果表明:①2011—2023年,山东省水土流失面积、强度实现了“双下降”,水土流失面积减少了5287.37 km 2,降幅达19.40%;全省水土流失以轻度为主,其面积占全省水土流失面积的54.77%~94.94%;全省水土保持率呈持续增长趋势,2023年较2011年增加了3.34个百分点。②2020—2023年山东省水土流失面积和强度“双下降”态势比2011—2023年的更好,水土保持工作呈高质量快速发展的趋势。③2020—2023年耕地、林地、建设用地是全省水土流失的主要源地,其水土流失面积占全省水土流失面积的88%以上,是水土流失重点防治和关注区域。④2020—2023年,山东省坡耕地绝大部分水土流失发生在坡度≤15°耕地,在水土保持规划中应重点关注,同时应加大对坡度≤2°耕地的水土流失治理力度。⑤2020—2023年山东省水土流失相对集中分布在鲁中南低山丘陵土壤保持区和胶东半岛丘陵蓄水保土区,两区水土流失面积占全省水土流失面积的94%左右,是水土流失重点关注区域,尤其应加大对鲁中南低山丘陵土壤保持区的水土保持工作力度。分析了山东省水土流失变化的原因,提出了水土流失综合防治对策。
基金supported by the National Natural ScienceFoundation of China(42204003,42274011,42388102,42192533,42192531)the Natural Science Foundation of Wuhan(2024040701010027)+1 种基金the Open Fund Supported by the State KeyLaboratory of Precision Geodesy,Innovation Academy for PrecisionMeasurement Science and Technology,Chinese Academy of Sci-ences(SKLGED2024-1-1)the Open Fund Supported by KeyLaboratory of Polar Environment Monitoring and Public Gover-nance(Wuhan University),Ministry of Education(202401)。
文摘Long-period free oscillations provide robust information for the spatio-temporal characteristics of large earthquakes.In this study,we employ a normal-mode summation algorithm to generate threecomponent seismograms within an aspherical,anelastic,and rotating Earth model,focusing on the excitation of seismic normal modes by the 2011 Tohoku megathrust earthquake.Specifically,we analyze the effects of seismic source parameters,including fault geometry,focal depth,and rupture duration.By comparing synthetic free oscillation spectra with observed data,we validate several source mechanisms and emphasize the need for horizontal observations to improve seismic mechanism inversions.Our quantitative analyses reveal that among fault geometry parameters,dip and slip angles have a more pronounced impact on excitation amplitudes than fault strikes.Certain fault configurations enhance the detectability of specific modes,underscoring the relationship between fault geometry and mode excitation.Normal modes also exhibit varying sensitivity to focal depth,with significant excitation amplitude changes at discontinuity boundaries.Additionally,we demonstrate that while rupture duration can be inferred by minimizing differences between observed and synthetic spectra,more extensive records and modes should be included.
