Comparison of tide model outputs for the northern region of the Antarctic Peninsula using satellite altimeters and tide gauge data     

《Polar Science》2014,8(1):10-23

This study compares the common harmonic constants of the O₁, K₁, P₁, Q₁, M₂, S₂, N₂, and K₂ tidal constituents from eight global and four regional tide models with harmonic constants from satellite altimeter and tide gauge data for the northern region of the Antarctic Peninsula (58°S–66°S, 53°W–66°W). To obtain a more representative comparison, the study area was divided into three zones with different physical characteristics but similar maximum tidal amplitude variations: Zone I (north of 62°S), Zone II (south of 62°S and west of the Antarctic Peninsula), and Zone III (between 62°S and 64.3°S, and east of 58.5°W). Root sum square (RSS) values are less than or equal to 3.0, 4.2, and 8.4 cm for zones I, II, and III, respectively. No single model shows superior performance in all zones. Because there are insufficient satellite altimetry observations in the vicinity of Matienzo Base (64.9761°S, 60.0683°W), this station was analyzed separately and presents the greatest values of both root mean square misfit and RSS. The maximum, minimum, and average amplitude values of the constituents that follow in importance after the eight common tidal constituents, and which have amplitudes greater than 1 cm, are also analyzed.  相似文献   

山东诸城早白垩世莱阳期古地震事件与恐龙迁移   总被引：1，自引：0，他引：1  

何碧竹  乔秀夫  田洪水  张艳霞 《地质学报》2012,86(8):1320-1330

在诸城断陷皇华镇大山村黄龙沟存在丰富的、多样的恐龙足迹化石,在紧邻化石埋藏层下伏及上覆地层中发现了下白垩统莱阳群杨庄组多套古地震记录,主要包含波状褶皱、底劈构造、液化砂岩脉、液化角砾岩、粒序断层、卷曲变形和震积不整合等塑性、脆性软沉积物变形构造。分析表明初始沉积物、沉积相及构造作用确定了地震活动作用时形成的软沉积物变形构造类型。在早白垩世莱阳群沉积中期,地震活动具有阶段性及频发性,以单向挤压的丘-槽构造及双向挤压的波状变形为主,且后期有构造活动强度加大的特征。根据已识别的古地震记录发育及古地震活动强度分析,推测此时期发震断裂可能是断陷的南缘断裂——五莲断裂。区域构造作用使得该时期沉积环境发生变化,由湖相逐渐过渡到河流相,在突发古地震事件发生之后,在滨浅湖区域留下了丰富的恐龙迁徙足迹。古地震记录的研究,可建立古地震事件与沉积、构造演化的联系,约束构造作用的属性、频次及时限,为确定盆地及周缘构造-沉积演化历史提供证据。  相似文献   

中国历代灾害性海潮的特点、成因及防治措施     

朱晓华  王建 《海洋科学进展》1998,(3)

本文以《中国历代灾害性海潮史料》为基础,对中国历代灾害性海潮的特点进行了初步研究,探讨了中国历代灾害性海潮随时间演进的月际和年际发生特征、主要发生类型、危害性及主要危害区域、分形性质。在此基础上,还初步探讨了灾害性海潮的成灾原因及相关防治措施。  相似文献   

赵各庄井水位水温演化特征及其成因分析     

韩孔艳  邢成起  崔博闻  孔来顺  孙小入 《地震》2019,39(3):178-186

平谷赵各庄井深200 m, 观测含水层为182 m以下的全井段, 是浅层冷水和深层热水的混合水。 受开采及降雨影响, 水位、 水温长趋势及年动态具有同步协调性变化, 地下水开采使井筒内冷水比例变小, 水位下降, 水温上升; 降雨渗入补给使流入观测井筒内冷水占比例变大, 水位上升, 水温下降, 但雨季结束, 井筒内冷水流入量变少, 井水温逐渐回升。 气压和固体潮使井筒与含水层间有水流运动, 水位出现周期性波动, 从而改变井筒内冷热水比例, 引起水温周期性变化的次生效应, 两者有短期同步协调变化。 不同种干扰因素造成了不同周期的变化影响, 在排除干扰, 提取地震异常信息时, 应选用不同方法及取样周期进行分析。  相似文献   

DISCUSSING THE INFLUENCE OF MAJOR EARTHQUAKE SEQUENCE IN THE LONGMENSHAN AREA ON THE LUSHAN EARTHQUAKE FROM STRESS EVOLUTION     

LIAO Li  LI Ping-en  YANG Jian-si  LIU Pan  FENG Jian-zhou 《地震地质》2018,40(2):450-464

Calculating the coseismic static Coulomb stress change induced by an earthquake and interseismic stress change permits to explain the distribution of aftershocks, the earthquake sequence and other seismic observations. Four earthquakes greater than M7 have occurred in the Longmenshan area before the 2013 Lushan earthquake since 1900. This paper analyzes the influence of these four events on the Lushan earthquake, the stress evolution after the Lushan earthquake accompany with strong earthquake sequence on Longmenshan Fault, and the stress state of the gap between the Lushan and Wenchuan earthquakes. To address these issues would help future seismic risk assessment in the region. We construct a three dimensional finite element model based on the geological structure, the deep inversion results of density and velocity, and the GPS and the stress observation data. The simulation results show that the annual variation rate of Coulomb stress is higher on the Xianshuihe fault and southern segment of the Longmenshan fault, which is consistant with the regional seismicity. The coseismic Coulomb stresses induced by Kangding, Songpan, and Wenchuan earthquakes at the Lushan earthquake epicenter is greater than 0, implying that the three earthquakes may promote the occurrence of the Lushan earthquake, especially the Wenchuan earthquake. The viscous relaxation is remarkable which cannot be ignored in the analysis of stress evolution. From the stress evolution of this area, we can find that the gap between the Wenchuan and Lushan earthquakes is still at a relatively high stress level after the Lushan earthquake.  相似文献   

DYNAMIC CHARACTERISTICS OF SEA CURRENTS AND SEDIMENT DISPERSION IN THE YELLOW RIVER ESTUARY   总被引：5，自引：0，他引：5  

HU Chunhong  JI Zuwen  WANG Tao 《国际泥沙研究》1998,(2)

ＤＹＮＡＭＩＣＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＳＥＡＣＵＲＲＥＮＴＳＡＮＤＳＥＤＩＭＥＮＴＤＩＳＰＥＲＳＩＯＮＩＮＴＨＥＹＥＬＬＯＷＲＩＶＥＲＥＳＴＵＡＲＹＨＵＣｈｕｎｈｏｎｇ１,ＪＩＺｕｗｅｎ２ａｎｄＷＡＮＧＴａｏ３ＡＢＳＴＲＡＣＴＤｙｎａｍｉｃ...  相似文献   

GS—15型重力仪滤波效能与观测稳定性的对比分析     

杨又陵  蔚晓利 《内陆地震》1998,12(3):215-221

通过观察和模拟干扰源试验,认为红山地震台ＧＳ－１５型重力仪潮汐观测曲线畸变和观测精度氏是因原配ＲＣ滤波电路的抗干扰能力差。用自制的有源贝赛尔滤波电路取代原配ＲＣ滤波电路后,观测质量得到了根本的改善,一系列参量的分析表明,ＧＳ型重力仪弹性系统手换能电路性能优良,有源滤波电路具有很强的抗干扰能力,使用数字记录代替模拟记录可以减小记录系统非线性失真,提高潮汐分析的精度和稳定性。  相似文献   

THE COSEISMIC SOURCE SLIP AND COULOMB STRESS TRIGGERING OF 2015 NEPAL GORKHA M_W7.9 AND KODARIM_W7.3 EARTHQUAKE BASED ON InSAR MEASUREMENTS          下载免费PDF全文

ZHANG Ying-feng  ZHANG Guo-hong  SHAN Xin-jian  WEN Shao-yan 《地震地质》2017,39(1):104-116

According to the structure of the Himalayan orogenic belt, a low-angle antilistric thrust-slip fault model is used to simulate the ramp on the rupture portion of the Main Himalayan Fault. Based on descending Alos -2 and Sentinal -1 data, we invert for the coseismic slip models of the Gorkha earthquake and its largest aftershock, Kodari earthquake. In contrast to the inversion using Alos -2 or Sentinal -1 separately, the joint inversion of both data sets has stronger constraint for the deep slip and can obtain more details in Gorkha earthquake. The rupture depth obtained by joint inversion can be as deep as 24km underground, cutting across the locking line to the transition of locked and the creeping zone. The largest slip is as large as 4.5m appearing 17km underground and the dip angle is between 3°and 10°. Gorkha and Kodari earthquakes have the similar focal mechanisms, both of which are mainly thrusting, and yet some right-lateral slip component in Gorkha earthquake. The inversion results reveal that slip models of the Nepal mainshock and its largest aftershock are complementary in space and the Kodari earthquake occurs in the gaps of slip in Gorkha earthquake. The epicenter of the Kodari earthquake is just right in the transitive zone of the positive and negative Coulomb stress change, where the Coulomb stress change can reach 0.4MPa. We thus argue that Kodari earthquake has been triggered by the Gorkha earthquake.  相似文献   

THE STATIC STRESS TRIGGERING INFLUENCES OF THE 2015 M_W6.4 PISHAN,XINJIANG EARTHQUAKE ON THE NEIGHBORING AREAS          下载免费PDF全文

JIN Zhi-tong  WAN Yong-ge  HUANG Ji-chao  LI Xiang  ZHANG Shan-shan 《地震地质》2017,39(5):1017-1029

Based on the rupture models of the 2015 Pishan M_W6.4 earthquake and half space homogeneous elastic model, the Coulomb stress changes generated by the earthquake are calculated on the active faults near the earthquake region. The horizontal stress changes and the displacement field are estimated on the area around the epicenter. Results show that:(1)The Coulomb stress is decreased in the west of the western Kunlun frontal thrust fault(9.5×10³Pa), and increased in the east of the western Kunlun frontal thrust fault and the middle of the Kangxiwa faults. More attention should be taken to the seismic rick of the east of the western Kunlun frontal thrust fault; (2)Based on the analysis on the location of the aftershocks, it is found that most of the aftershocks are triggered by the earthquake. In the region of increased Coulomb attraction, the aftershock distribution is more intensive, and in the area of the Coulomb stress reduction, the distribution of aftershocks is relatively sparse; (3)The horizontal area stress increases in the north and south of the earthquake(most part of the Qaidam Basin and the northwest of the Qinghai-Tibet plateau), and decreases in the east and west of the earthquake(northern part of the Qinghai-Tibet plateau and eastern part of the Pamir Mountains). In the epicenter area, the principal compressive stress presents nearly NS direction and the principal extensional stress presents nearly EW direction. The principal compressive stress shows an outward radiation pattern centered on the epicenter with the principal extensional stress along the direction of concentric circles. The principal compressive stress presents NW direction to the west of the epicenter, and NE to the east of the epicenter. With the increase of radius, the stress level gradually decays with 10⁷Pa in the epicenter and hundreds Pa in the Maidan Fault which is in the north of the Qaidam Basin.  相似文献   

Application of artificial neural networks in tide-forecasting   总被引：3，自引：0，他引：3  

T. L. Lee  D. S. Jeng   《Ocean Engineering》2002,29(9)

An accurate tidal forecast is an important task in determining constructions and human activities in ocean environments. Conventional tidal forecasting has been based on harmonic analysis using the least squares method to determine harmonic parameters. However, a large number of parameters are required for the prediction of a long-term tidal level with harmonic analysis. Unlike conventional harmonic analysis, this paper presents an artificial neural network (ANN) model for forecasting the tidal-level using the short term measuring data. The ANN model can easily decide the unknown parameters by learning the input–output interrelation of the short-term tidal records. Three field data with three types of tides will be used to test the performance of the proposed ANN model. The numerical results indicate that the hourly tidal levels over a long duration can be predicted using a short-term hourly tidal record.  相似文献