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1.
宽频带地震仪具有采样信号频带宽、动态范围广及采样精度高的特点,常布设于野外流动地震台站中进行长时间的地震观测,利用宽频带地震仪及由其组成的观测系统进行科学研究已成为近年来的发展趋势．由于野外环境存在大量不确定因素,这些变化可能会导致宽频带地震仪性能改变,从而影响数据质量．现场检测作为地震仪器性能检测的一种方法,无需改变仪器的布设位置能够保证仪器采集的连续性,同时考虑野外现场因素的影响．因此,宽频带地震仪性能的现场检测也越来越受到国内外学者的重视．本文以野外宽频地震仪性能检测为研究方向,从仪器性能的影响因素、原位校准方法以及利用观测数据评估仪器性能这三个角度出发：（1）论述了布设位置及方式、温湿度及大气压力变化对仪器性能的影响;（2）介绍了仪器原位校准中的电测法和对比测量法;（3）总结了利用地震信号、地震背景噪声以及潮汐信号对宽频地震仪性能进行现场检测的方法．最后,本文对目前宽频地震仪性能检测方法存在的问题进行分析总结,并对其发展前景提出展望． 相似文献
2.
针对海底地震仪在文件存储,数据通信等方面的观测要求,在海底地震仪的研制中引入了eCos（Embedded Configurable Operating System）系统,开发了基于该系统的具有数据采集、文件存储、仪器状态控制、网络数据通信、无线通信等功能的海底地震仪控制软件.本文在对海底地震仪的系统结构和工作模式作简要说明的基础上,重点介绍了eCos系统构建过程,海底地震仪控制软件的结构,指出该软件系统可有效地提高海底地震仪观测系统运行的稳定性和可靠性. 相似文献
3.
李洪胜 《地震地磁观测与研究》1996,(5)
ＤＫ－１型地震仪拾震器工作不稳定的改进李洪胜（中国黑龙江密山地震台１５８３００）１问题的出现黑龙江省密山地震台多年来在标定ＤＫ－１型地震仪垂直向拾震器时都遇到调整周期困难，周期变化显得灵敏度太高，不是长就是短，很难调到１５秒。有时好不容易调到１５秒，... 相似文献
4.
H.Huang ;B.Carande ;R.Tang ;J.Oiler ;D.Zaitsev ;V.Agafonov ;H.Y.Yu ;孙宏志 ;赵龙梅 ;卢山 ;刘一萌 ;高业欣 ;吕春来 《世界地震译丛》2014,(5):109-114
描述了一种基于分子电子传感器（MET）技术的微型机械地震计的研制过程。不同于固体惯性质量,分子电子传感器地震计是探测液体电解质相对于固定电极的移动。使用微机电系统技术将探测单元的内部尺寸减小到1μm并且提高了设备的再现性。对600mV的工作偏置电压,在0.32Hz的400μg（g≡9.81m/s2）加速度条件下可测得灵敏度为809V/（m/s2）。在1Hz获得的噪声水平为-115dB（相对于（m/s2）/Hz~（1/2））。这项工作研发了一个可供选择小尺寸、高灵敏度、低本底噪声、高振动范围和独立安装角度的地震计设备。这有希望成为下一代行星探测用的地震仪。 相似文献
5.
地震仪灵敏度参数的精度直接决定了地动量记录恢复的准确度.在中国国家地震台网的四个台站布设了多套参考地震仪,分别用地震事件和地脉动噪声作为信号源,用相关分析方法计算了在线地震仪相对于参考地震仪的灵敏度.结果表明:地震事件和地脉动噪声在垂直、南北、东西三个分量均可稳定获取在线地震仪灵敏度的可靠估计,并且两种方法表现出良好的一致性.对于无法中断观测的在线地震仪而言,本文提出的利用地脉动噪声相关分析估计仪器灵敏度是一个有效方法.在测试的四个台站中,蒙城台和九江台两个台站部分分量灵敏度误差超过3%,其中蒙城台的垂直向和南北向误差将近 10%.分析结果表明,对中国国家地震台网地震仪的灵敏度进行普查非常有必要,这项工作对提高我国地震台站的观测数据质量具有重要意义. 相似文献
6.
《世界地震译丛》2017,(4)
概述了自主式光纤旋转地震仪(AFORS)野外测试的应用和发展,此地震仪利用萨格奈克效应直接测量地面地震源的旋转。自主式光纤旋转地震仪的主要优势在于它不受直线运动影响,可以直接测量地震期间产生的旋转分量。该系统包含一个专用的自主式信号处理装置,可以对旋转运动的测量计算进行优化,而基于互联网的遥感系统可以对自主式光纤旋转地震仪远程控制。实验研究表明,这两种设备在检测频带为0.83~106.15Hz时,可以保持精度不低于5.1×10~(-9)~5.5×10~(-8)rad/s,并且灵敏度呈线性变化。文中还给出了一些用AFORS-1连续监测波兰克雄日地震观测站旋转事件的实验结果。 相似文献
7.
电容式位移传感器具有灵敏度高、分辨力强、能检测10mμ甚至更小的位移,特别适合于宽频带、长周期地震仪的应用。本文是作者为 BSO 井下地震计系统研制的变间隙式电容位移传感器。文中分析了电容传感器的基本原理及其分布参数的影响,介绍提高电容传感器性能的一些措施以及达到的技术指标。 相似文献
8.
本文首先按照数字地震仪的数据传输方式对地震仪进行了分类（有线遥测地震仪、无线遥测地震仪、无缆存储式地震仪）;回顾了无缆存储式地震仪的发展历程,简单分析了无缆存储式地震仪的优点;并对目前国内外的无缆存储式地震仪进行了简单介绍和比较;最后展望了我国发展无缆存储式地震仪的可能性和应用前景.由于无缆存储式地震仪结构相对简单、技术相对成熟,研制开发相对比较容易,非常有利于我国进行自主研发,也是我国石油和天然气行业摆脱地震勘探仪器全部依靠进口的被动局面,在研发数字地震采集系统方面赶上国际水平的有利时机. 相似文献
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10.
数字地震仪的发展历史及展望 总被引：4，自引：4，他引：4
地震仪经历了光点，模拟和数字的变化，数字地震仪本身由16位发展到24位，其附属设备（电缆，检波器）也是到了不同程度的发展。近年来，I／O等公司利用MEMS技术研制了新型地震检波器，这一新的发展对于地震采集尤其是多分量采集带来重要影响。 相似文献
11.
We propose the method for determining temporal changes in the tidal response of the medium in active seismic areas. This method allows one to increase the sensitivity and time resolution of the standard moving average spectral method for more than an order of magnitude. In addition, this work presents the results of comparative analysis of temporal changes in the tidal response of the medium in space-time in the vicinity of the 9-magnitude earthquake in Japan that occurred on March 11, 2011. 相似文献
12.
《Geofísica Internacional》2014,53(2):153-162
The temperature sensitivity of the WRF model to changes in Total Solar Irradiance (TSI). The simulations were performed for a region centered over the North Atlantic Ocean, including portions of Eastern North America, Western Europe and Northwest Africa. Four simulations were run with different TSI values. Also, a fifth simulation was performed in which we varied the initial atmospheric conditions, in order to compare the effect on the temperature of both, changes in the TSI and initial atmospheric conditions. Comparing temperature monthly averages we found that changes in TSI and in the initial conditions have a measurable impact on temperature in the region of study. The sensitivity of the model using non-dimensional parameters was also estimated. The numerical experiments show some features that might allow to distinguish between the effects on the temperature due to changes in TSI from those caused by initial conditions. However, TSI changes are of the same order of magnitude than those of disturbances in the initial conditions. We also found that the mean monthly values of temperature over the full grid, did not present significant variations due to changes of either initial conditions or TSI. 相似文献
13.
Runjie Yuan David M. Kennedy Wayne J. Stephenson Lluís Gómez-Pujol 《地球表面变化过程与地形》2019,44(7):1377-1389
In this study laboratory experiments were used to explore the role of biofilms, formed by lithobiontic microorganism communities, in causing hourly surface changes of supratidal sandstone and the potential linkage to long-term rock decay. To isolate the influence of individual environmental factors (temperature and humidity) on rock surface changes (expansion and contraction), a colonized (biofilm-covered) and a non-colonized sandstone block (biofilm-free) underwent the same univariate microclimatic simulations closely controlled by an environmental chamber. Simulations were run under three different light conditions, with a natural light lamp on, on and off at 20-min intervals and off, to investigate the impact of light on rock surface dynamics. Measured with a traversing micro-erosion meter (TMEM), two-hourly microtopographic fluctuations of these two sandstone blocks were compared in the same environment. Induced by microclimatic variations, surface movements of significantly higher magnitude (12–120% under varying tempeature and 121–154% under varying humidity) and different change patterns were observed on the colonized block, indicating the primary role of biofilm in driving microtopographic fluctuations of supratidal sandstone. However, thermally driven changes of similar magnitude and pattern were observed on both surfaces, suggesting other mechanisms also operating on the non-colonized rock surface in this process. Due to the sensitivity of biofilm microorganism communities to light, the magnitude and pattern of surface changes was impacted by light condition. Because biofilms increased the magnitude and number of cycles of expansion and contraction of the experimental rock surface, we propose that lithobiontic biofilms facilitate the detachment of grains and granular disintegration on the rock surface, consequently contributing to rock decay and accelerating the rate of breakdown of supratidal rock. This short-term episode therefore needs to be superimposed on longer term studies to fully understand the role of biofilms in rock surface change. © 2019 John Wiley & Sons, Ltd. 相似文献
14.
Iman Mallakpour 《水文科学杂志》2013,58(2):245-254
AbstractThe Pettitt test is a non-parametric test that has been used in a number of hydroclimatological studies to detect abrupt changes in the mean of the distribution of the variable of interest. This test is based on the Mann-Whitney two-sample test (rank-based test), and allows the detection of a single shift at an unknown point in time. This test is often used to detect shifts in extremes because of the lack of distributional assumptions. However, the downside of not specifying a distribution is that the Pettitt test may be inefficient in detecting breaks when dealing with extremes. Here we adopt a Monte Carlo approach to examine the sensitivity of the Pettitt test in detecting shifts in the mean under different conditions (location of the break within the series, magnitude of the shift, record length, level of variability in the data, extreme vs non-extreme records, and pre-assigned significance level). These simulation results show that the sensitivity of this test in detecting abrupt changes increases with the increase in the magnitude of the shift and record length. The number of detections is higher when the time series represents the central part of the distribution (e.g. changes in the time series of medians), while the skill decreases as we move toward either low or high extremes (e.g. changes in the time series of maxima). Furthermore, the number of detections decreases as the variability in the data increases. Finally, abrupt changes are more easily detected when they occur toward the center of the time series.
Editor D. Koutsoyiannis Associate editor K. Hamed 相似文献
15.
Changes in the magnitude of oil pollution on five prototype study beaches on Israel's northern Mediterranean coast had been monitored at 2- to 4-weekly intervals from 21 November 1980 to 19 March 1981. Statistical analyses of these changes were employed to rank the beaches in order of decreasing self-cleaning capacity. Records of storm-induced wave data records for the winter of 1980–1981 were correlated to incidence of change in the magnitude of subsurface tarball pollution and the rate of emplaced fuel sample dissipation on the study beaches. Specific wave breaking processes, overtopping of offshore obstacles and wave refraction were singled out as accelerating or retarding wave energy transfer to the polluted beaches. Attribution of the occurrence of specific local littoral processes to observed change in beach pollution magnitude made it possible to assess potential oil spill damage. Elucidation of the causative processes provided theoretical corroboration for beach sensitivity ranking established earlier by statistical analysis. 相似文献
16.
In this study, the Cold Regions Hydrological Modelling platform was used to create an alpine snow model including wind redistribution of snow and energy balance snowmelt to simulate the snowpack over the period 1996–2009 in a small (33 ha) snow‐dominated basin in the Spanish Pyrenees. The basin was divided into three hydrological response units (HRUs), based on contrasting physiographic and aerodynamic characteristics. A sensitivity analysis was conducted to calculate the snow water equivalent regime for various combinations of temperature and precipitation that differed from observed conditions. The results show that there was large inter‐annual variability in the snowpack in this region of the Pyrenees because of its marked sensitivity to climatic conditions. Although the basin is small and quite homogeneous, snowpack seasonality and inter‐annual evolution of the snowpack varied in each HRU. Snow accumulation change in relation to temperature change was approximately 20% for every 1 °C, and the duration of the snowpack was reduced by 20–30 days per °C. Melting rates decreased with increased temperature, and wind redistribution of snow was higher with decreased temperature. The magnitude and sign of changes in precipitation may markedly affect the response of the snowpack to changes in temperature. There was a non‐linear response of snow to individual and combined changes in temperature and precipitation, with respect to both the magnitude and sign of the change. This was a consequence of the complex interactions among climate, topography and blowing snow in the study basin. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
17.
The diurnal periodicity of seismic events of different energy from the Greece earthquake catalog was studied. Earthquake samplings of different energy with a known level of magnitude of completeness were compiled. Parameters of the diurnal periodicity of earthquakes in different time and magnitude intervals were analyzed. Significant diurnal periodicity of earthquakes with M ≤ 4.1 was revealed. The most important result of the paper is the discovery of the diurnal periodicity of the representative earthquakes with M = 3.2–4.1. The diurnal periodicity of representative earthquakes cannot be explained at the base of the prevailing hypothesis considering the diurnal periodicity of earthquakes as an apparent phenomenon resulting from diurnal changes in the real sensitivity of the seismic network due to diurnal variations of seismic noise. 相似文献
18.
AbstractWe evaluate flood magnitude and frequency trends across the Mid-Atlantic USA at stream gauges selected for long record lengths and climate sensitivity, and find field significant increases. Fifty-three of 75 study gauges show upward trends in annual flood magnitude, with 12 showing increases at p < 0.05. We investigate trends in flood frequency using partial duration series data and document upward trends at 75% of gauges, with 27% increasing at p < 0.05. Many study gauges show evidence for step increases in flood magnitude and/or frequency around 1970. Expanding our study area to include New England, we find evidence for lagged positive relationships between the winter North Atlantic Oscillation phase and flood magnitude and frequency. Our results suggest hydroclimatic changes in regional flood response that are related to a combination of factors, including cyclic atmospheric variability and secular trends related to climate warming affecting both antecedent conditions and event-scale processes.Editor Z.W. Kundzewicz; Associate editor H. Lins 相似文献
19.
海原小山四分量钻孔应变观测相对标定和异常判定 总被引：1，自引：0，他引：1
对宁夏海原小山yRy-4型钻孔应变仪进行实地相对标定后,数据比标定前有明显好转,资料的相关性显著增强,这验证了海原小山钻孔应变观测资料具有较高的可信度。相对标定后的潮汐因子灵敏度明显提高,稳定度明显改善,出现显著的同步变化趋势,相关性明显增强,各元件均有正常背景。对比钻孔应变各元件观测数据变化曲线,在固原ML3.8级与定西ML6.6级地震震前出现的扭曲、转折、恢复现象,是地震前地下应变积累和调整所致,表现出明显震前的短临异常变化。释放能量较小的地震,曲线扭曲、下降、转折的异常变化幅度较小,反之变化较剧烈,但短临异常变化的时间基本在震前10至15天之间。 相似文献
20.
For a 4D seismic operation to be successful, it is important to know what kind of 4D signal we expect to observe, as well as its magnitude. Normally, in a 4D feasibility study, we use rock physics models to quantify the effect of fluid or pressure changes within the reservoir and calculate the corresponding effects to the seismogram. However, to find if the predicted changes are actually observable at a given field, a dedicated calibration procedure might give valuable insight. One such procedure for marine seismics is to gradually change the source strength by varying the firing pressure in order to detect the sensitivity threshold for a given subsurface reflection. This procedure would be practical and feasible if the change of the source signature changes linearly with the source pressure. However, non‐linear effects will lead to minor changes in the later arrivals of the source signature, the so‐called bubble. By investigating these introduced errors for a reasonable air‐gun array we conclude that the method is still feasible since we find it possible to control and diminish the impact of the introduced errors. 相似文献