海平面变化与地震关系初探

利用烟台、龙口、塘沽、秦皇岛、葫芦岛等海潮测站的海平面资料，对渤海沿岸海平面变化进行了分析研究，总结了几次较大地震前后海平面变化的特点。分析认为海平面变化与较大地震的发生有一定的关系，较大地震前后一般会产生地壳形变现象，地壳形变可以通过海平面的变化估算出变化的量值。     

海平面变化和地震前兆

通过消除对海平面资料主要周期和非周期因素的影响,订正海平面表征了验潮站地区相对的地形变信息.从渤海地区三次大地震的震例分析表明,大震发生前订正海平面的形变前兆相当明显,并表现出对中期预报具有一定意义的形变特征.订正海平面还能检出与中小地震有关的形变前的信息,文中并举出预测前兆形变成功的实例.      

地震前海平面异常变化和机理研究

根据国内外沿海大地震前后海平面变化的实例,分析海平面变化的前兆意义。资料证实,大部分近海大地震前存在局部海域可以识别的海平面异常变化。１９世纪以来,世界各地的验潮站记录了大量与地震有关的海平面变化实例,为定量分析提供了可能。最有代表的标准震例是１９４１年１１月葡萄牙亚速尔群岛８．３级大地震,我国渤海１９６９年７月在８日７．４级地震前后烟台站的验潮记录也显示出显著异常。海域构造环境和地震发生机制不同     

地壳形变与海平面变化

本文根据冰川和海平面变化资料，探讨地壳形变对冰川消长和海平面升降的响应，并由此得出可以解释相应的地球物理现象的有益结果。这些结果对地壳形变的测量和地震预报有重要意义。     

集成奇异谱分析和自回归滑动平均预测日本近海海平面变化

本文从日本沿岸选取了28个验潮站及联测的GPS站,利用奇异谱分析（Singular Spectrum Analysis,SSA）和SSA+自回归滑动平均（Auto Regression Moving Average,ARMA）方法预测了2014—2018年的近海海平面变化和地壳垂直变化.并用同时段的验潮及GPS的实际测量值进行验证,结果显示,SSA+ARMA预测的相对海平面精度为0.0357~0.0607 m,地壳垂直运动的精度为0.0049~0.0077 m,绝对海平面的精度为0.0433~0.0683 m,且三者SSA+ARMA的预测结果均优于只用SSA预测的结果.在此基础上本文利用SSA+ARMA预测了日本沿岸2019—2023年的近海绝对海平面变化,结果显示,2019—2023年的平均海面高较往年（2014—2018）升高0.0353 m,2003—2023年绝对海平面的变化率为0.0039 m·a^-1,预测结果较为理想.     

北天山流动水准重复测量资料的前兆异常特征初析

通过对北天山地区跨断层流动水准观测资料的分析,可以看出,北天山地区跨断层流动水准观测值的变化较好地反映了各断裂带、地震前后的地壳垂直形变运动特征.由于各断裂带、各测线与震中的距离不同,它们所反映出的地壳垂直形变运动特征和变化量也不相同.流动水准观测资料对北天山中西部地区5～6级以上地震有较好的震前反映,前兆信息明显.     

集成奇异谱分析和自回归滑动平均预测日本近海海平面变化

本文从日本沿岸选取了28个验潮站及联测的GPS站,利用奇异谱分析(Singular Spectrum Analysis, SSA)和SSA+自回归滑动平均(Auto Regression Moving Average, ARMA)方法预测了2014—2018年的近海海平面变化和地壳垂直变化.并用同时段的验潮及GPS的实际测量值进行验证,结果显示,SSA+ARMA预测的相对海平面精度为0.0357～0.0607 m,地壳垂直运动的精度为0.0049～0.0077 m,绝对海平面的精度为0.0433～0.0683 m,且三者SSA+ARMA的预测结果均优于只用SSA预测的结果.在此基础上本文利用SSA+ARMA预测了日本沿岸2019—2023年的近海绝对海平面变化,结果显示,2019—2023年的平均海面高较往年(2014—2018)升高0.0353 m,2003—2023年绝对海平面的变化率为0.0039 m·a~(-1),预测结果较为理想.     

垂直形变强度分析在地震预报中的应用

根据数学上曲面拟合度的概念定义－－平均垂直形变量，来定量分析研究地壳表面垂直形变的强度，这一量值同时值有系统分析性质一统计意义。采用５０－９０年代中国大陆趋势性的垂直移计算结果，并利用定方法研究了中国在陆垂直形变强度背景值的分布特征及其与地震危险性的关系；利用华北地区１９６５－１９８８年多期垂直形变资料，研究了１９７６年唐山７．８级大地震的前后华北地区垂直形变强度随时间变化的动态过程，得到了强震的     

地壳形变与地震前兆探索回顾和展望

本文回顾了我国地震预报中地壳形变观测技术、 数据处理方法和软件及地壳形变前兆观测研究进展。 1966年邢台地震后, 我国地震预报工作经历了难得的成功、 更多惨痛失败和“地震不可预报论”等干扰, 发展曲折。 尽管2008年汶川和2011年东日本大地震预报失败,但这两次和其他大地震前后GPS和其他观测得到的地壳形变表明, 大地震是有前兆的, 是可以预报的。 比较了我国地震预报所采用的主要的地形变观测技术和分析方法, 讨论了观测和数据处理方法的特点, 简要介绍了地壳形变地震前兆新近的研究结果, 重点阐述了GPS观测技术多方面的优势。 事实证明, GPS观测得到的汶川大地震前的形变异常或前兆, 是我国地壳形变观测与地震前兆探索最突出的成果。     

2016年日本本州东岸近海MS7.2地震前后的地壳运动

2016年11月22日日本本州东岸近海发生东日本M_W9.0大地震的M_S7.2强余震。本文利用美国内华达大学内华达大地测量实验室网站获得此次大地震周围共30多个GPS连续观测站及其它台站的IGS08全球参考框架坐标时间序列,采用北京附近的GPS连续观测站BJSH作为区域位移参考框架的核心站,获取了此次M_S7.2强余震的同震水平位移和区域参考框架位移时间序列,得到了此次强余震前后的位移时空变化图像。结果显示:尽管本州东岸近海M_S7.2地震作为东日本M_W9.0地震的强余震,受其震后形变的影响强烈,但其地壳水平形变的前兆规律与已观测到的大地震一致;不同的是东日本M_W9.0地震前的垂直位移无积累,而本州东岸近海M_S7.2地震前后的垂直位移保持M_W9.0地震后均匀而缓慢的衰减变化;临震前震中附近的GPS连续观测站的东西分量明显减速,有的甚至减至零,是明显的短期前兆异常。此外,本文还进一步讨论了两种同震位移及其成因,并推断地壳水平运动挤压是此次地震的成因。      

Geodetic observation of sea-level change and crustal deformation in the Baltic Sea region

Based on tide gauge observations spanning almost 200 years, homogeneous time series of the mean relative sea level were derived for nine sites at the southern coast of the Baltic Sea. Our regionally concentrated data were complemented by long-term relative sea-level records retrieved from the data base of the Permanent Service for Mean Sea Level (PSMSL). From these records relative sea-level change rates were derived at 51 tide gauge stations for the period between 1908 and 2007. A minimum observation time of 60 years is required for the determination of reliable sea-level rates. At present, no anthropogenic acceleration in sea-level rise is detected in the tide gauge observations in the southern Baltic. The spatial variation of the relative sea-level rates reflects the fingerprint of GIA-induced crustal uplift. Time series of extreme sea levels were also inferred from the tide gauge records. They were complemented by water level information from historic storm surge marks preserved along the German Baltic coast. Based on this combined dataset the incidence and spatial variation of extreme sea levels induced by storm surges were analysed yielding important information for hazard assessments. Permanent GPS observations were used to determine recent crustal deformation rates for 44 stations in the Baltic Sea region. The GPS derived height change rates were applied to reduce the relative sea-level changes observed by tide gauges yielding an estimate for the eustatic sea-level change. For 13 tide gauge-GPS colocation sites a mean eustatic sea-level trend of 1.3 mm/a was derived for the last 100 years.     

Preliminary study on variation characteristics of ocean tide dynamic stress in crust and its relationship with earthquakes

~~Preliminary study on variation characteristics of ocean tide dynamic stress in crust and its relationship with earthquakes@陆明勇$China Center for Earthquake Disaster Emergency and SAR,Beijing 100049,China @郑文衡$Huazhong University of Science and Technology,Wuhan 430074,China①Strong earthquake catalogues in China. Earthquake catalogues reported monthly by Center for Analysis and Prediction, CEA. ①YI Zhi-gang. Institute of Crustal Dynamics, China Earthquake Administrati…     

平均海平面变化与地震的关系——海城地震前的平均海平面变化

对多年来在我国渤海沿岸五个验潮站的海平面连续记录资料进行了各种改正和处理之后, 发现1975年海城地震前平均海平面出现大范围稳定持续的上升趋势, 震中区附近该平面的变化更为显著, 并表现为突发性的变化.但1969年在同区发生的渤海大地震之前, 则平均海平面经历了长趋势的下降.      

Discussion on Characteristics of Crustal Deformation along the Zhangjiakou-Bohai Sea Seismotectonic Zone

INTRODUCTIONThe Zhangjiakou-Penglai fault zone has drawnextensive attentionfromseismologists and geologistssince it was determinedinthe1980’s(Zheng Binghua,et al.,1981).Ma Xingyuan,et al.(1989)consideredit asthe north boundaryof North China sub-block.Int…     

Regional characteristics of the effects of the El Niño-Southern Oscillation on the sea level in the China Sea

Based on coastal tide level, satellite altimetry, and sea surface temperature (SST) data of offshore areas of China’s coast and the equatorial Pacific Ocean, the regional characteristics of the effects of the El Niño-Southern Oscillation (ENSO) on the sea level in the China Sea were investigated. Singular value decomposition results show a significant teleconnection between the sea level in the China Sea and the SST of the tropical Pacific Ocean; the correlation coefficient decreases from south to north. Data from tide gauges along China’s coast show that the seasonal sea-level variations are significantly correlated with the ENSO. In addition, China’s coast was divided into three regions based on distinctive regional characteristics. Results obtained show that the annual amplitude of sea level was low during El Niño developing years, and especially so during the El Niño year. The ENSO intensity determined the response intensity of the annual amplitude of the sea level. The response region (amplitude) was relatively large for strong ENSO intensities. Significant oscillation periods at a timescale of 4–7 years existed in the sea level of the three regions. The largest amplitude of oscillation was 1.5 cm, which was the fluctuation with the 7-year period in the South China Sea. The largest amplitude of oscillation in the East China Sea was about 1.3 cm. The amplitude of oscillation with the 6-year period in the Bohai Sea and Yellow Sea was the smallest (less than 1 cm).