泰安台近震震级量规函数的修正

地震震级与诸多地震研究工作有着密切的关系,因此精确测定震级是非常重要的。我台测定的近震震级与《山东省地震台网观测报告》震级存有较大的偏差。本文对影响震级偏差的R_1(△)进行了修正,得到了适用于本台的新的量规函数R_3(△)。用R_1(△)和用R_3(△)计算的震级平均偏差分别为0.09和0.01,其相应的标准误差分别为±0.182和±0.150,已提高了我台测定震级M_L的精度。     

中国近震震级量规函数研究

在中国近震震级标度系统的基础上,依据我国大部分区域的实际观测资料,本文通过震级残差统计分析和近震最大震相平均衰减形态的研究,确立了我国东部地区和西部地区的中国近震震级量规函数R_(LE)(Δ)和R_(LW)(Δ),并约定了它们的使用区域。 中国东部地区:(Δ≤120km) (Δ≥120km) 中国西部地区:(Δ≤120km) (Δ≥120km) R_(LE)(Δ)和R_(LW)(Δ)的确立,突出反映了我国东部地区和西部地区的地震和地壳介质的地区性差异,是对中国近震震级标度系统的完善,它保持了近震震级测定的简单、方便、实用的优点,它的应用将减少震级测定值的离散度,提高区域台网测定近震震级的一致性。     

太原基准地震台数字地震仪震级偏差分析及校正

选用太原基准地震台2008年至2009年的数字化地震仪面波震级资料,以中国地震台网中心正式报告给出的震级为标准震级,进行了震级偏差统计分析。结果表明,该台的绝大部分震级偏差△M≤0．2级,部分地区地震震级偏差较大（超过0．3级）需进行校正。     

新疆地区近震震级与面波震级经验关系初步研究

利用线性回归方法对2010～2018年Ms≥3.5的500个地震事件为研究对象,重新量取计算近震震级ML和面波震级Ms,并对新疆地区分区域进行对比分析,得出不同区域近震震级与面波震级之间的关系,为定量研究地震震级奠定基础.同时,将新疆台网和中国地震台网都存在的震级数据进行对比,结果表明:新疆台网和中国地震台网测定的ML...     

宁夏地区区域起算函数的探讨

对发生在宁夏境内及邻区的地震,宁夏地震台网测定的震级与区外台网测定的震级有时相差较大。本文应用1982年至1986年间的124次地震,讨论了宁夏地震台网近震震级M_(LN)与甘肃省地震台网近震震级M_(LG)、面波震级M_(SB)、《中国地震台网观测报告》的面波震级M_(SB)的关系,以及宁夏地震台网震级与台网内15个台的震级关系,并用震级残差方法给出了适合于宁夏地区的区域起算函数和各台站校正值。     

乌鲁木齐台NCDSN长周期记录面波震级的测定及比较

引言震级是衡量地震能量大小的重要参数,对地震活动性的判定和地球物理研究起着相当重要的作用。面波震级是在国际上用得十分广泛的震级量,因此全球台网测定震级的一致性就显得十分重要。由美国地震情报中心（ＮＥＩＣ）管理的全球世界标准地震台网（ＷＷＳＳＮ）台站所装备的地震仪比较一致,测定ＭＳ的方法也较严谨,所以ＮＥＩＣ测报的ＭＳ值在国际上具有较高的权威性［１］。由于历史的原因,我国始终都没有采用ＩＡＳＰＥＩ推荐的面波震级公式,再加上地震仪频带的差异,使我国测定的面波震级普遍高出ＮＥＩＣ震级０．２～０．３级。…     

辽宁台网近震震级的归一化问题和限幅震级的测定方法

本文分析了影响近震震级M_2精度的因素.用计算和多次迭代的办法,计算出了近震震级M_L的起算函数在辽宁地区的矫正以及辽宁台网16个台站的校正值.同时又对辽宁台网限幅震级进行了多亢回归分析,并对结果进行了数学检验.我们认为:在地震发生限幅的非正常情况下.可以参考本文给出的统计公式计算地震震级.     

辽宁数字遥测地震台网的监控能力

辽宁数字遥测地震台网全部采用速度记录。我们将地动速度转换为地动位移，并统计出相应的最大振幅、周期，根据短周期地震仪近震震级公式ML＝lgAμ＋R（△）＋S对各遥测台站对不同震级所能控制的距离进行了计算，得到台网监测范围。台网基本上能够控制我省中部ML≥2．0以上地震和全省及邻近海域ML≥3．0以上地震。     

中国近震震级M_L综述

本文回顾了1959年中国近震震级标度公式建立以来近震震级研究的进展。在调查分析全国三十余个地方台网(包括传输台网)M_L震级测定现状的基础上,围绕着中国近震震级的统一和标准化,较系统地论述了区域量规函数、台站校正、测定值离散度和误差、仪器影响以及测定近震震级的其他方法、中国近震震级和Richter原始M_L震级的关系等主要问题。     

巴塘国家基本数字地震台数字地震仪记录近震震级偏差分析与校正

分析了巴塘国家基本数字地震台2009年1月初至2012年12月底测定的ML≥2.5级的近震544个,与中国地震台网中心（CSN）发布的ML震级之间的偏差,计算出了震级偏差程度,本台近三分之一地震震级偏差达0.3级,文章着重从地震发生的方位角不同和地动位移不同,找出了震级相差很大的原因,最后给出了本台的校正值。通过本台校证,震级接近了中国地震台网中心发布的ML震级,提高了本台地震震级测定的准确性。     

SCIENCE CHINA Earth Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Distribution of throughfall and stemflow in multi‐strata agroforestry,perennial monoculture,fallow and primary forest in central Amazonia,Brazil

The partitioning of rain water into throughfall, stemflow and interception loss when passing through plant canopies depends on properties of the respective plant species, such as leaf area and branch angles. In heterogeneous vegetation, such as tropical forest or polycultural systems, the presence of different plant species may consequently result in a mosaic of situations with respect to quantity and quality of water inputs into the soil. As these processes influence not only the water availability for the plants, but also water infiltration and nutrient leaching, the understanding of plant effects on the repartitioning of rain water may help in the optimization of land use systems and management practices. We measured throughfall and stemflow in a perennial polyculture (multi‐strata agroforestry), monocultures of peach palm (Bactris gasipaes) for fruit and for palmito, a monoculture of cupuaçu (Theobroma grandiflorum), spontaneous fallow and primary forest during one year in central Amazonia, Brazil. The effect on rain water partitioning was measured separately for four useful tree species in the polyculture and for two tree species in the primary forest. Throughfall at two stem distances, and stemflow, differed significantly between tree species, resulting in pronounced spatial patterns of water input into the soil in the polyculture system. For two tree species, peach palm for fruit (Bactris gasipaes) and Brazil nut trees (Bertholletia excelsa), the water input into the soil near the stem was significantly higher than the open‐area rainfall. This could lead to increased nutrient leaching when fertilizer is applied close to the stem of these trees. In the primary forest, such spatial patterns could also be detected, with significantly higher water input near a palm (Oenocarpus bacaba) than near a dicotyledonous tree species (Eschweilera sp.). Interception losses were 6·4% in the polyculture, 13·9 and 12·3% in the peach palm monocultures for fruit and for palmito, respectively, 0·5% in the cupuaçu monoculture and 3·1% in the fallow. With more than 20% of the open‐area rainfall, the highest stemflow contributions to the water input into the soil were measured in the palm monocultures and in the fallow. Copyright © 1999 John Wiley & Sons, Ltd.     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

Anthropogenic Eutrophication and Red Tide Outbreak in Lacustrine Systems of the Kashmir Himalaya

Red tide, a recurrent phenomenon has become conspicuous in several Kashmir lake ecosystems since 1991. The responsible organism (Euglena pedunculata), a rare flagellate rediscovered in the Kashmir Himalaya (Khan 1993) caused first and unprecedented red tide outbreak, constituting a maximum of 96% of resident numerical phytoplankton density in Dal Lake. At present, conflicting hypotheses exist on the generation of causal assemblage(s) imparting redness to waters: Jeeji Bai (1991) linked its origin to acid precipitation – a fallout of burning oil‐fields during the Gulf War – whilst Khan (1993) holds local factor(s) responsible. Field/experimental studies support the latter contention that the influx of untreated sewage, in unison with warm temperatures, high levels of PhAR, iron and interruption to hydrological flow‐pattern together with absence/or reduction in grazing activity created conducive environmental milieu for red tide outbreak. Dal Lake “red tide” drifted the bloom‐inoculum to other waters, including Lake Wular, where additional ecological niches were carved out, threatening the aesthetic value and biological diversity of Kashmir lakes. Ecological monitoring indicates frequent seasonal red tide occurrence in Dal Lake (including summer‐autumn event of 1998) which testifies its unabated eutrophication status. Further studies are needed on ecological adaptability and biogeographic distribution of this rare and unique red tide‐causing flagellate.