唐山地震前兆场的分布特征

本文对唐山地震昌黎等七个台的地电阻率日均值时间序列进行了关联维计算．取每年为一个时间段，其目的在于探索分数维对地震各个阶段的反应，以便达到利用分数维进行地震预报的目的。计算结果表明大部分地电台的地电阻率在地震前有明显的降维特征。通过地震前后七个台的地电阻率分数维的变化，得到了地震前后前兆场的分布特征，这一结果对于未来震源区的判定有重要意义。     

不等周期断层形变测量环境因子影响的研究

本文在研究和分析环境因子对断层测量年周变和季节性变化影响的基础上，归纳出断层形变测量年周变的变化规律，并针对不等周期观测资料，建立了形变测量的准线性动态数学模型，最后，对门源地震有异常的扁都口资料用上述模型进行了处理，结果是比较满意的。     

Research on the regionalQ values of coda waves for the aftershocks in Luquan,Yunnan of 1985

Based on the scattering coda model by which local and regional earthquakes are interpreted (K. Aki, 1969), and using observational coda data of 68 aftershocks of the 1985 Luquan, Yunnan earthquake registered by the VGK seismographs installed at 12 stations in the Yunnan regional short-period network, theQ-values of coda waves are calculated respectively for 6 time intervals. It is observed that within the frequency range of 0.40–1.65 Hz of the observed data, theQ-values are closely related with the frequencies and the calculated codaQ ranges between 80–240 with the coefficient of frequency dependence η=0.45. The calculated source factorsB(f> _p) of the coda waves which indicate the scattering strength are mostly within the order 10^?23–10^?24. Areas with lowQ-values present high scattering. It should be noted that by comparing data obtained before and after the Luquan earthquake, clear changes can be detected in theQ-values measured at stations close to the epicentral region, and that theQ-values of the aftershock coda are less than about one half of the pre-shock values. It may be mentioned that the time-dependent regional variations of theQ-values might possibly bring about practical significance in earthquake prediction. Moreover, aftershock focal parameters are determined. Through discussions on the quantitative relations between the focal parameters, we get: 1gE=1.59M _L+ 11.335;E=(2.10 × 10^?5)M ₀; length of focal rupturea=0.40?0.80 km for 3.0≤M _L<5.0 events; stress drop Δσ=(6.0–130) ×10⁵ Pa. Through interpretation of the data, we have also learned the important characteristics that there is no linear relation between the stress drops and the earthquake magnitudes.     

复波场的实部和虚部对同时源波形反演的影响

高精度的成像需要准确的速度场信息,波形反演被认为是目前具有最高分辨率的速度反演方法之一.计算效率是目前全波形反演需要考虑的一个主要问题.为了很好地解决计算效率的问题,本文引入了一种高效的无串扰同时源反演方法,并详细介绍了其原理与计算流程.同时,基于此多震源同时反演方法,本文拓展出实波场反演、虚波场反演及复波场反演的三种反演策略,进而分析复波场的实部和虚部对全波形反演的影响.实验表明,相比于复波场全波形反演,无论是实波场反演还是虚波场反演,反演分辨率有所降低;相比于实波场反演,虚波场反演对初始模型的依赖性较小,目标函数的非线性较弱;最后,通过使用组合反演策略,即初始阶段采用虚波场反演,中后期阶段采用复波场反演,不仅可以降低反演的非线性,而且能够保证高精度建模.

     

前兆数据库备份软件开发与应用

根据实际工作中前兆数据库的备份,研究了数字化地震前兆数据库的自动备份方法,解决了日常数据库备份过程中影响数据访问、占用大量备份时间、容易出现备份失败等问题。主要介绍了前兆数据库自动冷备份软件功能设计和实现、开发流程、运行环境。该软件提高了数据库备份效率,方便数据库迁移,工作中该软件运行稳定,保证了备份数据的完整性和一致性。     

区域地震信息网站简易备份策略和实现

本文在综合分析地震行业区域中心门户网站基础架构的基础上,根据地震信息发布的安全需求,对网站数据备份与恢复的技术和策略进行了分忻,提出了一种简单易行的网站数据备份与恢复的流程和机制,并在实际应用中得到运用。该方法简单实用和易行,为网站技术系统的运行维护提供了一种借鉴模式。     

Post-earthquake investigation on several geosynthetic-reinforced soil retaining walls and slopes during the Ji-Ji earthquake of Taiwan

This paper gives an overview on the application of geosynthetic-reinforced soil structures in Taiwan. Taiwan has an unique topography and geotechnical conditions that rendered a less conservative and more challenging design compared to that of North America, Europe and Japan. The Ji-Ji (Chi-Chi) earthquake of 1999 gave an opportunity to examine the behavior of reinforced soil structures. The performance of several modular-block reinforced soil retaining walls and reinforced slopes at the vicinity of the fault was evaluated. Reinforced structures performed better than unreinforced soil retaining walls. The failure cases were highlighted and the cause of failure was identified. The lack of seismic design consideration could be a major cause of failure. The compound failure mode, the inertia force of the blocks, and the connection stiffness and strength relative to the large dynamic earth pressure, were among major items that would warrant further design consideration.     

内陆河流生态环境需水量定量研究

在有限的水资源中,必须维持合理的生态环境需水量,以满足国民经济持续发展和生态平衡维护的需要,以内陆河流为对象,以生态学理论和水环境容量理论为基础,从维持河流系统水生生物生存、维持水体一定量稀释自净能力以及防止河流水面净蒸发损失的角度出发,分析计算了河流系统的生态环境需水量,以期为水资源合理配置提供科学依据。