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1.
利用改进的自动经验基线校正方法SMBLOC,对2016年8月24日意大利佩鲁贾MW 6.2级地震震中周围约60 km内的近场强震记录进行基线校正并尝试给出同震位移场,与GPS观测结果进行对比分析,分别独立和联合两种资料反演震源滑动模型,并根据震源模型进一步给出全空间预测位移场分布.研究结果表明:(1)两种不同的资料给出的水平位移场幅值均为cm级,且均表明断层的错动以正断为主.(2)两种同震位移场分别独立和联合反演所得的震源静态滑动范围基本一致,最大滑动均发生在震中东北侧,强震模型表现出明显的双事件特征,较大滑动分布在震中东北侧和东南侧,GPS模型在震中东南侧的滑动相对较小,其双事件特征不明显.两种模型的最大滑动量分别为0.96 m和0.86 m,较为一致,反演的矩震级均在MW 6.3左右.(3)根据震源滑动模型计算所得的佩鲁贾地震全空间预测的水平同震位移场中最大位移分布区域与震后报告中受灾严重的地区基本一致.表明在一定的条件下,利用SMBLOC方法解算震级较小的MW 6.0左右地震强震记录的同震位移场,并反演震源滑动模型具有一定的可行性,且其同震位移场和滑动模型可为震后灾害快速评估、救援力量分配、余震趋势判定等快速应急响应工作提供参考依据.  相似文献   
2.
The MW6.6 Arketao earthquake occurred on November 25, 2016 in Muji Basin of the Kongur extensional system in the eastern Pamir. The region is the Pamir tectonic knot, one of the two structural knots where the India plate collides with the Eurasian plate. This region is one of the most active areas in mainland China. The seismogenic structure of the earthquake is preliminarily determined as the Muji dextral-slip fault which locates in the north of Kongur extensional system. Based on field surveys of seismic geological hazard, and combined with the characteristics of high altitude area and the focal mechanism solution, this paper summarizes the associated distribution and development characteristics of sandy soil liquefaction, ground fissures, collapse, and landslide. There are 2 macroscopic epicenters of the earthquake, that is, Weirima village and Bulake village. There are a lot of geological hazards distributed in the macroscopic epicenters. Sand liquefaction is mainly distributed in the south of Kalaarte River, and area of sand liquefaction is 1 000m2. The liquefaction material gushed along the mouth of springs and ground fissures, because of the frozen soil below the surface. More than 60% of soil liquefactions are formed in the mouth of springs. According to the trenching, these liquefactions occurred in 1.8 meters underground in the gray green silty clay and silty sand layers. The ground fissures are mainly caused by brittle failure, and the deformation of upper frozen soil layer is caused by the deformation of lower soil layer. The ground fissures at Weirima village are distributed in a chessboard-like pattern in the flood plain of Kalaarte River. In the Bulake village, the main movement features of the ground fissure are tension and sinistral slip, and the directions of ground fissures are 90°~135°. The collapse and landslide are one of the important geological disasters in the disaster area. The rolling stones falling in landslide blocked the roads and smashed the wire rods, and the biggest rolling stone is 4 meters in length. We only found a small landslide in the earthquake area, but there are a large number of unstable slopes and potential landslides in the surroundings. The ground fissures associated with sand liquefaction are an important cause of serious damage to the buildings.  相似文献   
3.
The surface ruptures produced by the 2016 MW7.8 Karkoura earthquake, New Zealand are distributed in a belt with~170km long and~35km wide, trending generally in the NE-SW direction. There are at least 12 faults on which meter-scale displacements are identified and they were formed across two distinct seismotectonic provinces with fundamental different characteristics(Hamling et al., 2017; Litchfield et al., 2017). Although the trending directions of the seismic surface ruptures vary greatly at different locations, the ruptured faults can be generally divided into two groups with the NE to NEE direction and the NNW to N direction, respectively. The faults in the NNW-near NS direction are nearly parallel with 40~50km apart and featured by reverse movement with the maximum displacement of 5~6m. The faults in the NE-NNE direction, with the maximum of 25~30km apart are not continuous and featured by the dextral strike slip with the largest displacement of 10~12m. Even if some faults along the NE-NEE direction are end to end connected, their strikes differ by about 30°. The combination styles of the strike-slip fault surface ruptures along the NE-NEE direction can be merged into 3 categories, including en-echelon, bifurcation and parallel patterns. The scales of the fault surface ruptures with the same structural style could be obviously different in different areas, which results in significant changes in the widths of deformation zone, from tens of meters to hundreds of meters. En-echelon distributed surface rupture(section)can appear as a combination belt of meter-scale to dozens of meter-scale shear fracture with bulge and compressional shear fractures, and also can be characterized by the combination of the left-step en-echelon tensile shear fractures with a length of more than one hundred meters. The step-overs between surface rupture sections are clearly different in sizes, which can be dozens of meters, hundreds of meters to several kilometers. The spacing between parallel surface ruptures can be several meters, dozens of meters to several kilometers. Besides, as one of the prominent characteristics, the seismic surface ruptures caused by the Karkoura earthquake broke through the known distribution pattern of active faults. The surface ruptures can occur either on the previously thought inactive or unmapped faults, or break through the distribution range of previously realized active faults in the striking or lateral direction. The basic features about the distribution and widths of the surface ruptures induced by the 2016 MW7.8 Karkoura earthquake, New Zealand presented in this paper might be helpful for understanding some seismic problems such as complex corresponding relationship between the active faults and the deep seismogenic structure, and the necessary measurements for engineering crossing active faults.  相似文献   
4.
The NE-trending Hinagu fault zone, length 81 km, is one of the major active faults in Kyushu, Japan. From north to south, it is divided into three segments based on geomorphic features and paleoseismic behavior: the Takano-Shirahata, Hinagu, and Yatsushiro Sea segments. The 2016 Kumamoto earthquake produced a 6-km-long surface rupture with a dextral strike-slip displacement on the northern part of the Takano-Shirahata segment. Surface rupture, a faint east-side-up flexure with a vertical offset of less than 8 cm, was observed near the middle of the Takano-Shirahata segment. To examine past surface-rupturing earthquakes on the Takano-Shirahata segment, including rupture frequency and timing, we conducted a paleoseismic study with boring and trenching at Yamaide. A trench across the surface rupture exposed multiple fault strands associated with multiple surface-rupturing events that deformed several strata of fine-grained sediments. By structural and stratigraphic interpretation, high-density radiocarbon dating and tephra analysis, and Bayesian modeling, we constrained the timing of seven events, Events 1–7, to 0.84–1.25, 1.31–7.06, 9.99–11.0, 10.8–12.1, 12.0–13.0, 14.2–15.1, and before 14.8 kcal BP. Slip during Events 1–6 was obviously larger than the 2016 slip. The estimated average recurrence interval was about 2596–2860 years, but the interval between Events 2 and 3 was much longer than other intervals. Moreover, the vertical throw associated with Event 2 was larger than that of other events. This implies that the Takano-Shirahata segment has a period with rare larger earthquakes and a period with frequent smaller earthquakes. Some events might have produced ruptures on both the Takano-Shirahata and the northern part of the Hinagu segments simultaneously or in a short time. The variety of recurrence intervals suggests that the seismic activity has been affected by one or both activities of the Futagawa fault zone and the Hinagu segment.  相似文献   
5.
本文研究建立2015/2016年极强厄尔尼诺事件下我国动力和统计结合的气候预测模型,并开展2015年夏季和2016年冬季气候我国160个站点和主要区域实时气候预测。夏季降水的实时预测起报于2月,冬季气温的预测起报于10月。研究结果表明,尽管NCEP-CFSv2耦合气候模式能较好预测2015/2016年极强厄尔尼诺事件中海温异常的演变,但对我国160个站点夏季降水和冬季气温预测仍有较大的偏差。因此,基于NCEP-CFSv2耦合模式预测结果,分别建立我国160个站点冬季气温和夏季降水异常的动力和统计结合气候预测模型。同时,利用年际增量预测方法开展我国长江中下游夏季降水和华北冬季气温的区域气候预测。研究结果表明以上预测模型在2015/2016年的实时预测中较NCEP-CFSv2有更好的预测效能。相对于NCEP-CFSv2耦合模式的预测结果,2015年夏季降水距平空间相关系数ACC从0.21提高到0.31(超过0.01信度的显著性水平),距平同号率提高到60%,2016年冬季气温ACC从0.19提高到0.32(超过0.01信度的显著性水平),距平同号率提高到75%。  相似文献   
6.
利用NOAA海表温度和NCEP/NCAR大气环流等全球再分析资料,讨论了2015/2016年超强El Nio事件局地海气过程的演变特征,并与1982/1983和1997/1998年两次强El Nio事件做了对比分析。结果表明,2015/2016年El Nio在峰值强度、持续时间、累计海温距平等指标上都略强于前两次El Nio,可视为有完整气象观测纪录以来的最强事件;与前两次事件相比,2015/2016年El Nio海温异常中心位置明显偏西,热带东太平洋海温相对较冷而中太平洋更暖,由于热带对流对海温的非线性响应,赤道东太平洋降水相对较弱,中太平洋则显著偏多,这在El Nio当年12月至次年4月尤为明显;此外,在前两次El Nio的成熟期至衰减期,中太平洋大气响应都存在明显的南移特征,西风异常和对流中心都从赤道南移到了5°S以南。而2015/2016年中太平洋大气响应一直位于赤道附近,南移特征相对较弱,ENSO和年循环相互作用的组合模态相比前两次较弱,西北太平洋反气旋的强度也弱于前两次。这主要是由于2015年冬季至2016年春季,热带太平洋暖海温异常位置偏西,中太平洋海温异常明显强于前两次,叠加气候平均态海温之后,赤道南北两侧海温都高于对流阈值,对流旺盛,这大大削弱了大气响应的经向移动和ENSO组合模态的强度。  相似文献   
7.
本文利用HYCOM (Hybrid Coordinate Ocean Model)再分析数据对北赤道流(NEC)、棉兰老流(MC)以及黑潮(KC)所构成的NMK环流系统在2015/2016年超强厄尔尼诺事件期间的变化特征及其影响机制进行了研究,并与其他厄尔尼诺期间的变化特征进行了对比。结果表明,在2015/2016年超强厄尔尼诺事件期间,NEC和MC输运均显著增强,最大值分别达到66 Sv (1 Sv=106 m3/s)和49.4 Sv,北赤道流分叉纬度最北可达16°N,KC输运没有明显增强。NMK环流系统的年际变化主要与此次厄尔尼诺事件期间热带西北太平洋15°N以南、160°E以西海域出现的气旋式环流异常有关。该环流异常出现自厄尔尼诺事件的前期阶段,并于爆发阶段达到顶峰,主要是由15°N以南区域出现的强西风异常所引起的。进一步分析表明,此次厄尔尼诺事件期间NEC、MC输运和NBL的平均值均大于1992— 2014年间所有厄尔尼诺事件的平均状况,但与1997/1998年超强厄尔尼诺事件期间的平均值相近。  相似文献   
8.
60~100 km低电离层对无线电传播、测量具有重大影响。IRI2016作为目前最新的国际参考电离层模型,研究其提供的电子密度在高度60~100 km的精度具有重要实际意义。本文以廊坊中频雷达(位于中纬度地区)提供的电子密度资料(2014—2016年)为基准,利用偏差、绝对差、相关系数、相对偏差和Lomb-Scargle周期图方法,定量分析了IRI2016模型电子密度在中纬度地区60~100 km高度范围内的精度特征。结果表明,在中纬度地区60~100 km高度范围内:①电子密度偏差、绝对差、相对偏差与季节有密切关系,在高度86~100 km,随高度增加均快速增大;相关系数同样与季节有密切关系,但随高度增加表现出增大、减小的交替变化特征;②IRI2016模型电子密度精度与太阳活动、地磁条件有关,在太阳活动低年、磁宁静条件下的电子密度精度最高;③中频雷达和IRI2016模型电子密度在82~84 km均显著(通过90%显著性检验)含有准全日潮汐波、准8 h重力波,同时IRI2016模型还显著含有准半日潮汐波,而中频雷达未显著含有准半日潮汐波;在86~92 km均显著含有准全日潮汐波、准半日潮汐波,无准8 h重力波;④中频雷达、IRI2016模型电子密度在同一高度层显著含有的波周期及功率谱存在差异,不同高度层之间显著含有的波周期及功率谱也存在差异;⑤对于高度82~92 km的中频雷达、IRI2016模型电子密度变化特征,准全日潮汐波均为主要作用,准8 h重力波在82 km为次要作用,而准半日潮汐波在86~92 km为次要作用。  相似文献   
9.
中纬度夏季夜间异常(midlatitude summer nighttime anomaly,MSNA)区域内的总电子含量(total electron content,TEC)的日变特性存在季节性差异,能否有效描述MSNA的特征是检验电离层TEC经验模型精度的关键指标之一。针对MSNA现象,提出了一种适合MSNA区域的单站电离层TEC经验模型,命名为SSM-T2(single station model type2)模型;以位于MSNA区域内的南极半岛上的奥伊金斯站(ohi3)为例,验证了该模型的有效性。SSM-T2模型由3部分组成,分别是TEC日变化分量、季节变化分量和随太阳活动分量,模型中的系数由非线性最小二乘拟合得到。在南极半岛的ohi3站上,模型拟合测试结果表明,SSM-T2-ohi3模型与建模数据GPS-TEC拟合得很好,较好地描述了MSNA现象。通过模型对比分析发现,在外推时间点上,SSM-T2-ohi3与CODE GIMs、SSM-month模型符合得很好,能有效描述MSNA的特征,具有较好的预测能力,且总体上优于IRI2016模型。  相似文献   
10.
2016年新西兰凯库拉MW 7.8地震中,北东—北东东向科科仁古断裂水平右旋位移量最大,为10—12m;北北西—近南北向帕帕提断裂垂直位移量最大,达到5—6m。对直接坐落在这2条地震地表破裂带或变形带之上的建筑物的破坏现场调查表明,尽管房屋出现歪斜,但上部主体部分基本完整,没有出现倒塌或部分倒塌现象,避免了人员伤亡。在无法回避活动断裂及其大震危险性的情况下,隔震系统的广泛采用可以有效地提高建筑物抵御地震灾害的能力。此次地震触发了数万个滑坡体,最大滑坡体可达数百万立方米。对沃罗村北边2处边坡失稳地带的考察结果表明,针对该地至少从2个方面进行了考虑和处置:一是在选址上,避开了突出山嘴等高陡坡地带;二是在房屋正对的山坡地带,种植或保护了茂密的树木,这既增加了山体的稳定性,又可以在地震中有效地减缓崩塌的石块对房屋的冲击。对比中国中东部一些大震,如1976年唐山7.8级地震和2008年汶川8.0级地震中触目惊心的巨大人员伤亡和财产损失,即使在人口密度与滑坡规模上存在明显不同,对新西兰凯库拉地震灾害现场的考察结果,还是在如何有效抵御地震灾害方面给我们提供了很好的启示。  相似文献   
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