Crustal deformation revealed by GPS in Kumaun Himalaya,India

The foremost Global Positioning System(GPS) derived measurements in the Kumaun Himalaya indicate that most of the crustal motion of the Indian plate is accommodating towards the base as well as on the hanging wall of Main Central Thrust(MCT).Deformation pattern within the Kumaun Himalaya varies from south to north and indicates maximum deformation rate near MCT.Our study,based on the campaign mode GPS survey during 2003- 2006,reveals that the area between north of North Almora Thrust(NAT) and at the base of Great Himalaya registers maximum strain rate,which is lowered towards the Trans Himadri Fault(THF).The GAMIT-GLOBK processed campaign data of the area show that currently,the Himalayan Frontal Fault(HFF) and Main Boundary Thrust(MBT) are locked with the Indian plate,and a 6.7 ± 2.5 mm/yr of horizontal shortening is taking place between the Lesser Himalaya and Peninsular India.     

2004年苏门答腊—安达曼M9级地震的下一代形变模型

2004年的苏门答腊—安达曼M9级地震将俯冲的印度—澳大利亚板块和仰冲的缅甸板块分裂开。这次地震的形变属于三维问题,为此我们构建了有限元模型进行模拟,以说明俯冲板块、弧前、火山弧及弧后的物性分布。同震形变的模拟使用一种基于协议的方法。该方法考虑俯冲带的地质复杂性,使用有限元模型反演估计断层滑动分布。结果表明不考虑俯冲带中物性差异的形变预测的灵敏度比近场GPS的测量误差可大一个数量级还多。本文介绍的基于有限元模型的技术可用于地质上相符的形变模型,提高同震与震后形变、应力耦合及海啸发生的基于模拟技术的评估可靠性。     

震后一分钟：强震图,有效震中和有效震级

本文报道了台湾实时地震监测的最新进展,尤其是台湾中心气象局遥测地震台网(CWBSN)的实时强震监测。该项工作旨在大震发生后迅即速报。如果速报能在强振动到来之前完成,那么地震早期警报将成为可能。CWBSN已能在大震发生后一分钟内给出强度图、震中和震级。速报和早期警报主要适用于大震(M>>5);不限幅波形记录的需要促使CWBSN在1995年将强震探测仪(如力平衡加速度计)并入其遥测地震监测系统中。将时间域递归处理应用于多道输入地震信号,通过一组联网微机生成强度图。通过等值线,能迅速识别出位于强度图最大等值线(通常为100gal)中央的有效震中。有效震级也能迅速由最大等值线(通常为100gal)覆盖的表面积确定。对于具有有限破裂面的大震,如此得出的震中和震级是更适当的震源位置和破坏强度的估算值。有效震中给出了破坏区域的中心,与传统的震中定位比较,后者仅给出了破裂形成的初始位置。有效震级所反映的更接近地震破坏的潜能,而不是强调总能量释放的传统震级。CWBSN已能在一分钟内获取上述震源的关键信息。这一时间将会进一步缩短至30s以内,如本文中举例描述的那样,地震早期警报的确是一个可能达到的目标。速报和早期警报信息将电传给用户,以采取人为或无人干予的快速反应行动。     

平坦低地农业区人类活动影响下地形对森林分布的影响（英文）

Complex topography buffers forests against deforestation in mountainous regions.However,it is unknown if terrain also shapes forest distribution in lowlands where human impacts are likely to be less constrained by terrain.In such regions,if important at all,topographic effects will depend on cultural-historical factors and thus be human-driven(anthropogenic) rather than natural,except in regions where the general climate or extreme soils limit the occurrence of forests.We used spatial regression modeling to assess the extent to which topographic factors explain forest distribution(presence-absence at a 48×48 m resolution) in a lowland agricultural region(Denmark,43,075 km2) at regional and landscape scales(whole study area and 10×10 km grid cells,respectively),how landscape-scale forest-topography relationships vary geographically,and which potential drivers(topographic heterogeneity,forest cover,clay content,coastal/inland location) determine this geographic heterogeneity.Given a moist temperate climate and non-extreme soils all landscapes in Denmark would naturally be largely forest covered,and any topographic relationships will be totally or primarily human-driven.At regional scale,topographic predictors explained only 5% of the distribution of forest.In contrast,the explanatory power of topography varied from 0%–61% at landscape scale,with clear geographic patterning.Explanatory power of topography at landscape scale was moderately dependent on the potential drivers,with topographic control being strongest in areas with high topographic heterogeneity and little forest cover.However,these conditioning effects were themselves geographically variable.Our findings show that topography by shaping human land-use can affect forest distribution even in flat,lowland regions,but especially via localized,geographically variable effects.     

A TEST OF SIGNIFICANCE FOR PARTIAL LEAST SQUARES REGRESSION

Partial least squares (PLS) regression is a commonly used statistical technique for performingmultivariate calibration, especially in situations where there are more variables than samples. Choosingthe number of factors to include in a model is a decision that all users of PLS must make, but iscomplicated by the large number of empirical tests available. In most instances predictive ability is themost desired property of a PLS model and so interest has centred on making this choice based on aninternal validation process. A popular approach is the calculation of a cross-validated r~2 to gauge howmuch variance in the dependent variable can be explained from leave-one-out predictions. Using MonteCarlo simulations for different sizes of data set, the influence of chance effects on the cross-validationprocess is investigated. The results are presented as tables of critical values which are compared againstthe values of cross-validated r~2 obtained from the user's own data set. This gives a formal test forpredictive ability of a PLS model with a given number of dimensions.     

Direct scaling of residual displacements for bilinear and pinching oscillators

The estimation of residual displacements in a structure due to an anticipated earthquake event has increasingly become an important component of performance-based earthquake engineering because controlling these displacements plays an important role in ensuring cost-feasible or cost-effective repairs in a damaged structure after the event. An attempt is made in this study to obtain statistical estimates of constant-ductility residual displacement spectra for bilinear and pinching oscillators wit...     

ON THE REGIONAL DIVISION OF THE MARINE ALGAL FLORA OF THE WESTERN NORTH PACIFIC

Although in the discussions of the geographic distribution of the marine algae in the western part of the North Pacific, the marine algal flora of this vast area has been variously divided by phycologist, there is, as yet, not a single satisfactory system for its regional division since in some cases the proposed floristic regions are too large and inclusive resulting in their heterogenous nature and in other cases, they are too minute or classified according to their political nature. In the present paper, an attempt is made to propose a system of objectively dividing this vast area into a number of major fioristic regions, based on the following two principles;     

FAST Observations of an Extremely Active Episode of FRB 20201124A: Ⅰ.Burst Morphology

We report the properties of more than 600 bursts(including cluster-bursts) detected from the repeating fast radio burst(FRB) source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio Telescope during an extremely active episode on UTC 2021 September 25–28, in a series of four papers. The observations were carried out in the band of 1.0–1.5 GHz by using the center beam of the L-band 19-beam receiver. We monitored the source in sixteen1 hr sessions and one 3 hr session spanning 23 ...