• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Correlation between the tilt anomaly on the vertical pendulum at the Songpan station and the 2021 MS7.4 Maduo earthquake in Qinghai province,China

    2022-11-03 07:25:46AnfuNiuZhengyiYuanJinWeiJingZhaoandWeiYan
    Earthquake Science 2022年3期

    Anfu Niu ,Zhengyi Yuan ,Jin Wei ,Jing Zhao and Wei Yan,?

    1 China Seismic Network Center, Beijing 100045, China

    2 Institute of Seismology, China Earthquake Administration, Wuhan 430071, China

    ABSTRACT Understanding the relationship between precursory deformation anomalies and strong earthquakes is vital for physical earthquake prediction.Six months before the 2021 MS7.4 Maduo earthquake in Qinghai province,China,the vertical pendulum at the Songpan station was observed to tilt southward with a high rate and large amplitude.Studies conducted before the 2021 MS7.4 Maduo earthquake inferred the tilt anomaly to be an earthquake precursor.However,after the earthquake,the relation between the earthquake and the anomaly became controversial,partly because the Songpan station is located at a great distance from the epicenter.In this study,based on the deformation anomaly characteristics,relationship between the seismogenic fault and the fault near the anomaly,and associated quantitative analyses,we concluded that this anomaly may be associated with the 2021 MS7.4 Maduo earthquake.The duration and amplitude of this anomaly matched with the magnitude and epicenter distance of the Maduo earthquake.We have also interpreted the reason why the anomaly occurred near a fault that is obliquely intersected with the seismogenic fault and why the anomaly is located far from the earthquake epicenter.

    Keywords: 2021 MS7.4 Maduo earthquake;tilt of the vertical pendulum at the Songpan station;far-field correlation.

    1.Introduction

    Monitoring fault slips to predict earthquakes was first proposed in the 1960s based on the characteristics of coseismic and tectonic deformation.Many scholars believe that seismogenic faults exhibit a pre-slip before a large earthquake (Rice and Rudnicki,1979).However,even a relatively dense deformation-monitoring network (that measures tilt,strain,cross-fault leveling,etc.) may not reveal a significant deformation anomaly in the vicinity of a seismogenic fault in a short term before an earthquake(Bilham,2005;Johnston et al.,2006;Amoruso and Crescentini,2010).This phenomenon contradicts the theoretical earthquake rupture model (Rice and Rudnicki,1979;Fang ZJ et al.,2010).Therefore,short-term earthquake prediction by monitoring crustal deformation on seismogenic faults,as practiced in China,the United States,Japan,and Italy,is accompanied by considerable uncertainties (Bakun et al.,2005).Prior to the 2008MS8.0 Wenchuan earthquake and 2010MS7.0 Yushu earthquake,no apparent anomaly was detected at the deformationmonitoring stations in the epicentral regions (Niu AF,2017;Niu AF et al.,2021).Additionally,deformation anomalies have been observed in areas adjacent to active faults without subsequent strong earthquakes.This suggests that our current understanding of the relationship between precursory deformation and earthquakes is insufficient and needs to be further elucidated (Knopoff,1999).

    In the absence of significant deformation near the epicenter before the earthquake,searching for source information from deformation at the periphery of the epicenter (field precursors),i.e.,inferring the source from the field,has been regarded as a viable method for earthquake prediction.However,determining the field precursors and their relationship with subsequent earthquakes is the main challenge that hinders the further development of this method.Previous studies have used static theory to identify earthquake precursors but have encountered various unexplained phenomena.

    The 2021MS7.4 Maduo earthquake occurred in Qinghai province,China,with a left-lateral rupture of 1.8–2.9 m (Pan JW et al.,2021).It was the strongest earthquake in Chinese mainland after the 2008MS8.0 Wenchuan earthquake,and is being studied in detail (Hu MZ et al.,2021).The lack of monitoring stations within 200 km of the epicenter of this earthquake reduces the deformation monitoring capacity of the region.No significant anomaly was detected at the three deformation observation sites located 200–350 km away from the epicenter.Furthermore,the cross-fault baseline and leveling observations sites are distributed in the Qilian-Longmenshan-Xianshuihe seismic zone,400 km away from the epicenter.However,six months prior to the 2021MS7.4 Maduo earthquake,the vertical pendulum at the Songpan station had significantly tilted southward,with a high rate and large amplitude,and is believed to be a preearthquake anomaly.The Songpan station is~560 km away from the epicenter,and is not on the same fault or tectonic boundary as the earthquake.In this study,we introduce the concept of crustal stress waves to interpret the relation of the tilt anomaly observed at the Songpan station in Sichuan before the Maduo earthquake.Exploring the correlation between the tilt anomaly and the Maduo earthquake will aid in understanding the distribution pattern of pre-earthquake deformation anomalies and developing the concept of earthquake prediction.

    2.Tilt of the vertical pendulum at the Songpan station

    The Songpan station is located at the intersection of the northern and eastern boundaries of the Bayan Har tectonic block (Figure 1).This Bayan Har block is bounded by the East Kunlun fault (EKLF),a left-lateral strike-slip fault in the north and by the Longmenshan fault (LMSF) and Minjiang-Huya fault,which are strike-slip faults with thrust components,in the east.

    Figure 1.Location of the Songpan station and distribution of earthquakes with magnitude ≥7.0 since 2010.EKLF: East Kunlun fault;LMSF: Longmenshan fault;XSHF: Xianshuihe fault.

    The vertical pendulum tiltmeter of the Songpan station is installed in an observation cave excavated in the mountain behind the office building of the station.The cave has a depth of 40 m,with seven thermal-insulating doors.The annual temperature difference inside the cave is<0.5°C.Instruments are installed in the relatively dry innermost cave chamber,which was previously a seismological observation room.

    The ground tilt has been measured at the Songpan station since March 2013,with two components in the NS and EW directions being monitored.Each component is observed using a 153 mm long lead pendulum (the corresponding self-vibration period is 0.78 s).The pendulum systems are sealed in jars,which are fixed onto the same foundation pier.However,the observation quality was unstable owing to various factors related to the station,environment,and instrument;therefore,the obtaining of measurements was discontinued in March 2016 and resumed in November 2016 after a series of optimizations.The obtained data have been reliable since then and show clear tilt tides.In late September 2020,an anomaly began,when the long-term northward tilt shifted to an accelerated southward tilt and started to decelerate in late January 2021.Fisher statistic was constructed to quantify the intensity of the anomaly using tilt variations of 2018 as standard and a moving window with a time-step of one month (Niu AF et al.,1998).A result of <1.0 is considered normal,and a value >1.0 is regarded as an anomaly.Our results showed a significant anomaly from late September 2020 to late January 2021 (Figure 2) for a duration of~110 days.The tilting amplitude is~1 300 ms after tidal correction.The time between the end of this tilt anomaly to the occurrence of the Maduo earthquake was~3.5 months.

    Figure 2.Variation curve of the southward tilt anomaly at the Songpan station and the results of the Fisher test.

    As a response,the China Earthquake Administration had sent an expert team to the station on January 7,2021 to investigate this anomaly.They inspected the observation system and confirmed that the instruments were operating properly and showing clear tilt tide curves.Furthermore,no significant disturbances were observed in the recorded meteorological parameters,such as temperature,precipitation,and atmospheric pressure.The observation cave had undergone maintenance in mid-October 2020,after which no significant rate change was detected.It was finally concluded that the anomaly might be precursory.Moreover,even after the NS tilt anomaly had begun,variations in the EW tilt were normal.However,a colleague at the Sichuan Earthquake Administration accidentally touched the instrument jar that monitors the EW tilt component while investigating the NS tilt anomaly on October 22,2020.This disturbed the vertical pendulum,which started tilting westward;thus,the EW tilting data of this period is not reliable.

    No apparent tilt anomaly was observed on the vertical pendulum at this station before the 2017MS7.0 Jiuzhaigou earthquake (epicenter distanceD=40 km).As mentioned in Section 1,this phenomenon can be partly explained by the locking effect of the seismogenic fault in the nearsource region before the earthquake.

    3.Correlation between the tilt anomaly at the Songpan station and the 2021MS7.4 Maduo earthquake

    Based on the deformation data of Chinese mainland since the 1980s,the precursory deformation anomalies are categorized into impending,short-term,and long-term,corresponding to a duration time of 1–4 days,15–180 days,and 1–3 years,respectively.Additionally,the time between the end of each type of precursory anomaly to the earthquake is 1 month,4 months,and 3 years,respectively.The current models describe the relationship between short-term deformation anomalies and earthquakes (Niu AF,2003,2017;Niu AF et al.,2020).

    3.1.The Maduo earthquake occurred within the dominant seismic waiting time

    The accelerated tilt anomaly at the Songpan station was a short-term anomaly,lasting for 110 days.The 2021MS7.4 Maduo earthquake occurred~3.5 months after the end of the southward tilt anomaly,i.e.,within the dominant seismic waiting time (Niu AF,2017).

    Earthquakes usually occur under conditions of decelerated deformation anomalies (Niu AF et al.,2021).Right before the Maduo earthquake,the rate of the southward tilt anomaly had decreased dramatically,from~12 ms/d during the anomaly to~1 ms/d.

    3.2.Duration of the anomaly matches the epicenter distance and earthquake magnitude

    A method has been developed to identify the correlation between short-term deformation anomalies and earthquakes (Niu AF et al.,2020).In addition to constraining the time of occurrence of the earthquake,the relationship between the duration of the anomaly (T),epicenter distance (D),and magnitude of the earthquake(M0) are also constrained.We introduce the quantitative constraint model as follows:

    whereD0=290 km,representing the half-wavelength of the long-period deformation wave or stress wave that can be obtained by characterizing deformation migration(Scholz,1977;Xu SX,2006;Niu AF et al.,2020).εfollows a normal distribution,with an expectationE(ε)=0 and the variance σ=0.28.

    If the difference between the estimated value and the actual magnitude of the target earthquake is less than twice the σ,the precursory anomaly is considered to be correlated with the target earthquake with a 95% probability.

    The duration of the southward tilt anomaly at the Songpan station was approximately 110 days,and its distance from the epicenter of the Maduo earthquake is approximately 560 km.According to Equation (1),the estimated magnitude of the target earthquake is 7.15.It differs by–0.25 from the actual magnitude,which falls within twice the σ of the model.Therefore,this tilt anomaly can be considered as related to the 2021MS7.4 Maduo earthquake with a 95% probability.

    3.3.Amplitude of the tilt anomaly matches the M-D model

    A model describing the relationship between the tilting amplitudeI(rad),D,andM0can be obtained based on the consistency between the amplitude of the short-term preearthquake accelerated tilt anomaly and the target earthquake (Niu AF,2003).

    IfIis known,Equation (2) can be simplified as

    whereC=1.14logI+11.87.Equation (3) describes the relationship betweenMandD,and is called theM-Dmodel.Dis a power function ofM,and does not have an extreme point or inflection point but can be used to examine the correlation between ground tilt anomalies and earthquakes.

    The tilting amplitude recorded at the Songpan station was 1 300 ms,and its correspondingM-Dcurve is shown in Figure 3.The actualPpoint (for the magnitude of the Maduo earthquake and the distance from the epicenter to the Songpan station) lies close to theM-Dcurve,suggesting that the magnitude and epicenter distance of the Maduo earthquake correspond to the amplitude of the tilt anomaly at the Songpan station.

    Figure 3.M-D model of the tilt anomaly and P-point correlation test for the Maduo earthquake.

    4.Discussion on the correlation between far-field precursory deformation and earthquakes

    4.1.Epicenter distance

    Precursory deformation anomalies were believed to be caused by the anomalous activities of seismogenic faults.However,since the beginning of this century,several observations have shown that significant deformation anomalies are scarcely detected near earthquake epicenters owing to the fault locking effect (Bilham,2005;Johnston et al.,2006;Amoruso and Crescentini,2010).Furthermore,it has been observed that deformation anomalies generally do not occur at the periphery of the fault.Therefore,the causes of such pre-earthquake anomalies observed at great distances from the epicenter and their relation with the earthquake should be explored.

    Crustal deformation is related to stress changes.Crustal stresses include in situ and transient stresses.In situ stresses,also known as static stresses or absolute stresses,are caused by long-term (geological) tectonic movements.Transient stresses,also called dynamic stresses,mainly originate from the rheology of deep materials and short-term interactions of crustal blocks.For instance,tectonic activities,such as earthquakes and volcanoes,can cause large changes in the crustal stress.Transient stresses fluctuate greatly and can be rapidly converted into transient strains; however,no clear relationship has been established between them.Slow earthquakes,with periods ranging from tens of seconds to hours and even days,and long-period deformation waves,with periods ranging from days to months,are both reflections of transient stress field variations (Scholz,1977;Feng DY et al.,1984).Co-seismic deformation,crustal tilt,strain,gravity field,and global navigation satellite systems (GNSS) are tools for observing transient stress field changes.Some deformation anomalies fluctuate spatiotemporally,indicating that the creep waves or crustal stress waves are generated by the migration of deep materials (Savage,1971;Bott and Dean,1973;Scholz,1977;Feng DY et al.,1984;Wang SJ and Yin ZS,1989;Niu AF et al.,1995;Niu AF,2017).

    The Songpan station is~560 km away from the epicenter of the 2021MS7.4 Maduo earthquake.Because of the long distance,the tilt anomaly at this station was not considered associated with the Maduo earthquake based on the view that earthquake precursors are caused by the activity of seismogenic faults.However,new insights were obtained from the migration pattern of deep materials.The distribution of gravity anomalies and lowQ-values can be used to estimate the migration trend of subsurface materials to a certain extent.The gravity anomaly map for the study area shows that in the last five years,large-scale positive (or negative) anomalies,extending >600 km,have occurred within the Bayan Har block,which is conducive to the migration of deep materials in the block (Figure 4).Both the Maduo earthquake and the Songpan station are located within the Bayan Har block.The anomalous tilt deformation at the Songpan station and the Maduo earthquake may be related to such migration.The time differences between these two events reflects the role of precursory deformation in triggering earthquakes (Scholz,1977).TheQ-value distribution in the middle and upper crust,obtained by inversion using the 2.0-Hz band Lgwave data,also reveals a lowQ-value anomaly of >600 km long within the Bayan Har block (Figure 5) (Zhao LF et al.,2013).Owing to the flow of deep materials,interaction between the anomalous tilt deformation at the Songpan station and the Maduo earthquake may be relatively direct,despite the surficial distance between them.

    Figure 4.Contour map of the gravity anomalies in the last 5 years (2016–2021).EKLF: East Kunlun fault;LMSF: Longmenshan fault;XSHF: Xianshuihe fault.

    Figure 5.Distribution of the Q-value (Zhao LF et al.,2013)and the 2021 MS7.4 Maduo earthquake epicenter.Grey lines represent the boundaries of secondary blocks.EKLF: East Kunlun fault;LMSF: Longmenshan fault;XSHF: Xianshuihe fault.

    4.2.Intersection of the deformation-related fault and the seismogenic fault

    The 2021MS7.4 Maduo earthquake occurred on a fault near the northern boundary of the Bayan Har block that obliquely intersects the LMSF,on which the Songpan station is located.Experimental studies have confirmed the phenomena of oblique fault intersections (Ma J et al.,1999,2000,2002;Niu AF,2017),and we have attempted to explain them in new light.

    With respect to crustal stress waves,both deformation migration and large-earthquake migration are results of subsurface material flow.Therefore,large-earthquake migration also supports deep-material migration.Four strong earthquakes of magnitude ≥7.0 occurred along the boundaries of the Bayan Har block after the 2008MS8.0 Wenchuan earthquake,i.e.,the 2010MS7.1 Yushu earthquake,2013MS7.0 Lushan earthquake,2017MS7.0 Jiuzhaigou earthquake,and 2021MS7.4 Maduo earthquake(present study).These four events occurred on the southern,eastern,and northern boundaries of the block(Figure 1),and were spatially distributed counterclockwise along the block boundaries at an interval of 3–4.3 years(Table 1).

    Table 1.Migration of MS ≥7.0 earthquakes along the boundaries of the Bayan Har block since 2010.

    The stage-wise migration of strong earthquakes around the Bayan Har block (Deng QD,2010) has occurred previously.During 1970–1976,a series of strong earthquakes occurred in the eastern Bayan Har and near the Yunnan-Sichuan blocks.TheMS7.6 Luhuo earthquake on February 6,1973,and twoMS7.2 Songpan earthquakes on August 16 and 23,1976,occurred in the eastern part of the block.The former is located on the Xianshuihe fault,and the latter on the Huya fault,with a counterclockwise distribution pattern along the boundaries of the Bayan Har block and an occurrence interval of~3.5 years.

    The counterclockwise migration of strong earthquakes along the boundaries of the Bayan Har block reflects the direction of asthenospheric-material migration within it.Distribution of the GNSS displacement rate (Figure 1),which data form Wang M and Shen ZK (2020),demonstrates that the movement along the south of the Xianshuihe fault (XSHF) is predominantly clockwise,with a counterclockwise motion near the LMSF.Gravity results(Figure 4) show the distribution of large-scale positive(negative) anomalies within the block,which are favorable to the counterclockwise flow of deep materials in it.TheQ-value inversion results (Figure 5) reveal the distribution pattern of lowQ-values within the block,also indicating a counterclockwise migration trend near the LMSF.

    The theory of crustal creep wave generation assumes(Savage,1971) that the fault at the bottom of the lithosphere is composed of a sequence of dislocation units.Shear stress generated because of the migration of asthenospheric materials causes absorption of the dislocation units or the aggregation of materials around a specific unit,and the latter leads to short-term accelerated deformation.When the materials accumulated around theunit are finally absorbed,i.e.,the accelerated deformation anomaly ends,the aggregated materials continue to migrate following the original direction or along the block boundary.Penetration of the fault at the bottom boundary reduces the probability of a major earthquake on it in the short term.Thus,faults where short-term deformation anomalies are observed are usually not seismogenic for large earthquakes.The creep wave model can also explain the deformation due to material flow in the middle and upper crust.The continued propagation of deep materials after reaching the fault intersection under shear stress and the mechanisms that trigger an earthquake near the obliquely intersecting faults need to be explored in future studies.

    5.Conclusions

    Owing to fault locking,the possibility of preearthquake deformation occurring near the epicenter is low.Therefore,the correlation between far-field deformation anomalies and earthquakes needs to be explored.We have obtained the following conclusions by quantitatively analyzing the tilt anomaly that occurred at the Songpan station before the 2021MS7.4 Maduo earthquake and discussing the related model.

    (1) The duration and amplitude of the tilt anomaly at the Songpan station was consistent with the magnitude and epicenter distance of the Maduo earthquake.Based on the duration of the anomaly and the epicenter distance,the magnitude of the target earthquake was estimated to be 7.15,similar to the actual magnitude of the Maduo earthquake.The magnitude and epicenter distance of the Maduo earthquake conform to theM-Dmodel derived from the amplitude of the tilt anomaly.

    (2) Geophysical field analysis revealed that the farfield correlation between the tilt anomaly at the Songpan station and the Maduo earthquake was related with the distribution of large-scale positive (negative) gravity anomalies and lowQ-values.Using the creep wave generation and propagation model proposed by Savage(1971),we discussed the cause of the short-term tilt variation at the Songpan station and the phenomenon whereby the fault near which the tilt anomaly was observed was obliquely intersected by the seismogenic fault.We believe that the blocking of deep-material migration may be a critical reason for the accelerated deformation.Additionally,the Maduo earthquake occurred on a fault that obliquely intersected with the Huya fault where the Songpan station is located.This observation is consistent with the counterclockwise migration trends of magnitude-7.0 earthquakes and deep materials along the boundaries of the Bayan Har block.

    Acknowledgments

    We sincerely thank the reviewers for their helpful comments on revising the manuscript.We thank Lianfeng Zhao,a researcher at the Institute of Geology and Geophysics,Chinese Academy of Sciences,for providing theQ-value data;Xuemei Zhang,a researcher at the Seismic Network Department of the China Earthquake Network Center,for assisting us in the research of seismic wave application;and Shengjie Lin,a research assistant at the Sichuan Earthquake Agency,for his help in the anomaly verification process.We would like to thank Editage (www.editage.cn) for English language editing.

    秋霞在线观看毛片| 久久久久国产网址| 国产免费一级a男人的天堂| 97人妻精品一区二区三区麻豆| 五月玫瑰六月丁香| 久久久色成人| 十八禁国产超污无遮挡网站| 亚洲电影在线观看av| 日本五十路高清| 午夜a级毛片| 成人国产麻豆网| 亚洲成人精品中文字幕电影| 九九在线视频观看精品| 欧美日韩综合久久久久久| 久久久久国产网址| 国内精品美女久久久久久| 美女大奶头视频| 舔av片在线| 国内精品宾馆在线| 99精品在免费线老司机午夜| 一区二区三区高清视频在线| 亚洲内射少妇av| 亚洲四区av| 亚洲第一电影网av| 少妇高潮的动态图| 亚洲欧美日韩无卡精品| 精品免费久久久久久久清纯| 99热这里只有是精品在线观看| 欧美潮喷喷水| 一进一出抽搐gif免费好疼| 国产成年人精品一区二区| 午夜福利在线观看吧| 中出人妻视频一区二区| 大香蕉久久网| 亚洲欧美成人综合另类久久久 | 精品熟女少妇av免费看| 亚洲精品色激情综合| 男女视频在线观看网站免费| 直男gayav资源| 欧美不卡视频在线免费观看| 国产一区二区在线观看日韩| 一级毛片久久久久久久久女| 老司机午夜福利在线观看视频| 国产亚洲精品av在线| 大型黄色视频在线免费观看| 欧美性感艳星| 欧美成人免费av一区二区三区| 内射极品少妇av片p| 免费看a级黄色片| or卡值多少钱| 欧美中文日本在线观看视频| 搡老熟女国产l中国老女人| 波多野结衣高清无吗| 成年女人永久免费观看视频| 色视频www国产| av专区在线播放| 99久久久亚洲精品蜜臀av| 国产精品人妻久久久影院| 亚洲成人久久爱视频| 国产精品永久免费网站| 国产毛片a区久久久久| 亚洲av中文av极速乱| 麻豆国产97在线/欧美| 好男人在线观看高清免费视频| 老师上课跳d突然被开到最大视频| av天堂中文字幕网| 亚洲精品色激情综合| 亚洲四区av| 天堂网av新在线| 亚洲电影在线观看av| 久久久久久久久久黄片| 日韩 亚洲 欧美在线| 免费一级毛片在线播放高清视频| 国产精品久久久久久亚洲av鲁大| 国产伦精品一区二区三区视频9| 99久久中文字幕三级久久日本| av免费在线看不卡| 久久久精品欧美日韩精品| 国产精品久久视频播放| 亚洲成a人片在线一区二区| 校园春色视频在线观看| 成人综合一区亚洲| 国产午夜精品论理片| 亚洲人成网站在线播放欧美日韩| 日韩av不卡免费在线播放| 男人舔女人下体高潮全视频| 97超视频在线观看视频| 一级毛片电影观看 | 亚洲一区高清亚洲精品| 国产色爽女视频免费观看| 日韩在线高清观看一区二区三区| 成年版毛片免费区| 成人毛片a级毛片在线播放| 日韩精品有码人妻一区| 亚洲av免费在线观看| 有码 亚洲区| 激情 狠狠 欧美| 国产成人a∨麻豆精品| 国产精品嫩草影院av在线观看| 日本撒尿小便嘘嘘汇集6| 看片在线看免费视频| 国产高潮美女av| 最好的美女福利视频网| 淫秽高清视频在线观看| 91久久精品国产一区二区三区| 97在线视频观看| 国产精品亚洲美女久久久| 少妇高潮的动态图| 悠悠久久av| 国产蜜桃级精品一区二区三区| 亚洲av熟女| 中出人妻视频一区二区| 日日摸夜夜添夜夜添小说| 1000部很黄的大片| 99在线人妻在线中文字幕| 高清毛片免费观看视频网站| 欧美丝袜亚洲另类| 极品教师在线视频| 免费观看精品视频网站| 久久鲁丝午夜福利片| 亚洲激情五月婷婷啪啪| 国产成人91sexporn| 国产精品女同一区二区软件| 女人十人毛片免费观看3o分钟| 亚洲aⅴ乱码一区二区在线播放| 午夜激情欧美在线| 亚洲天堂国产精品一区在线| 精品一区二区三区av网在线观看| 麻豆一二三区av精品| 国产精品一区二区三区四区免费观看 | 别揉我奶头 嗯啊视频| 又黄又爽又免费观看的视频| 成人av一区二区三区在线看| 欧美一区二区精品小视频在线| 欧美日韩在线观看h| 国产高清视频在线观看网站| 综合色av麻豆| 免费观看的影片在线观看| 夜夜夜夜夜久久久久| 女的被弄到高潮叫床怎么办| 欧美国产日韩亚洲一区| 成人亚洲精品av一区二区| 青春草视频在线免费观看| 亚洲最大成人中文| 日韩人妻高清精品专区| 欧美性猛交╳xxx乱大交人| 欧美成人精品欧美一级黄| 色综合色国产| 亚洲美女黄片视频| 亚洲精品色激情综合| 嫩草影院精品99| 一级毛片我不卡| 欧美中文日本在线观看视频| 久久久久久久亚洲中文字幕| 午夜日韩欧美国产| 一级黄色大片毛片| 大型黄色视频在线免费观看| 亚洲美女视频黄频| 激情 狠狠 欧美| 国产亚洲av嫩草精品影院| 国产精品久久久久久久久免| 97超碰精品成人国产| 91av网一区二区| 一区二区三区免费毛片| 国产精品伦人一区二区| 老师上课跳d突然被开到最大视频| 欧美潮喷喷水| 91狼人影院| 午夜福利在线观看免费完整高清在 | 99久久成人亚洲精品观看| 亚洲成人av在线免费| 麻豆久久精品国产亚洲av| 午夜影院日韩av| 国产高清视频在线观看网站| 亚洲av一区综合| 99久久精品国产国产毛片| 精品无人区乱码1区二区| 十八禁国产超污无遮挡网站| 伦精品一区二区三区| 亚洲av五月六月丁香网| 久久人人精品亚洲av| 日韩中字成人| 一本精品99久久精品77| 国产精品一区二区免费欧美| 亚洲精华国产精华液的使用体验 | 国产精品亚洲美女久久久| 能在线免费观看的黄片| 内地一区二区视频在线| av在线亚洲专区| 国产免费一级a男人的天堂| 搡老岳熟女国产| 精品午夜福利在线看| 午夜精品在线福利| 尾随美女入室| 国产高清视频在线观看网站| 免费黄网站久久成人精品| 亚洲成人久久性| 国产精品精品国产色婷婷| 直男gayav资源| 国产乱人视频| 久久久久九九精品影院| 精品少妇黑人巨大在线播放 | av在线蜜桃| 日本免费a在线| 老女人水多毛片| 亚洲av中文av极速乱| 99久久无色码亚洲精品果冻| 久久亚洲国产成人精品v| 久久99热这里只有精品18| 1024手机看黄色片| 国产成人freesex在线 | 国内精品一区二区在线观看| 97在线视频观看| 亚洲美女搞黄在线观看 | 成熟少妇高潮喷水视频| 日韩欧美 国产精品| 欧美激情在线99| 亚洲三级黄色毛片| 美女免费视频网站| 狂野欧美白嫩少妇大欣赏| 三级经典国产精品| 91久久精品国产一区二区三区| 亚洲国产精品久久男人天堂| 亚洲欧美日韩无卡精品| 最近2019中文字幕mv第一页| 国产视频一区二区在线看| 最近视频中文字幕2019在线8| 国产久久久一区二区三区| 久久热精品热| 一区二区三区免费毛片| 亚洲最大成人中文| 黄色视频,在线免费观看| 最近最新中文字幕大全电影3| 午夜影院日韩av| 国内精品宾馆在线| av福利片在线观看| 69人妻影院| 精品久久久久久久久久免费视频| 亚洲欧美成人综合另类久久久 | 亚洲va在线va天堂va国产| 日韩在线高清观看一区二区三区| 国产国拍精品亚洲av在线观看| 极品教师在线视频| 2021天堂中文幕一二区在线观| 18禁裸乳无遮挡免费网站照片| 久久亚洲国产成人精品v| 免费不卡的大黄色大毛片视频在线观看 | 免费av不卡在线播放| 舔av片在线| 亚洲在线自拍视频| 日韩制服骚丝袜av| 久久久国产成人精品二区| 不卡一级毛片| 99久久无色码亚洲精品果冻| 亚洲国产日韩欧美精品在线观看| 丰满人妻一区二区三区视频av| 久久久国产成人精品二区| 99久久久亚洲精品蜜臀av| 夜夜爽天天搞| 天天一区二区日本电影三级| 俄罗斯特黄特色一大片| 午夜视频国产福利| 亚洲国产欧洲综合997久久,| av黄色大香蕉| 国产精品av视频在线免费观看| 精品无人区乱码1区二区| 国产午夜福利久久久久久| 一级毛片电影观看 | 欧美xxxx黑人xx丫x性爽| 九九爱精品视频在线观看| 国产视频一区二区在线看| 亚洲熟妇熟女久久| 国产亚洲精品久久久com| 欧美高清成人免费视频www| 一区二区三区高清视频在线| 91在线精品国自产拍蜜月| 国产色爽女视频免费观看| 最好的美女福利视频网| 久久久久九九精品影院| 尾随美女入室| 精品乱码久久久久久99久播| 可以在线观看的亚洲视频| 搡老熟女国产l中国老女人| 免费av毛片视频| 精品无人区乱码1区二区| 免费av不卡在线播放| 国产av不卡久久| 简卡轻食公司| 内射极品少妇av片p| 久久久久久久久大av| 乱系列少妇在线播放| 亚洲无线观看免费| 久久久成人免费电影| 国产片特级美女逼逼视频| 在线国产一区二区在线| 国产蜜桃级精品一区二区三区| 99久久精品国产国产毛片| 午夜精品一区二区三区免费看| 小说图片视频综合网站| 国产蜜桃级精品一区二区三区| 六月丁香七月| 欧洲精品卡2卡3卡4卡5卡区| 免费看a级黄色片| 国产精品女同一区二区软件| 久久99热6这里只有精品| 97超碰精品成人国产| 日本五十路高清| 一区二区三区四区激情视频 | 美女 人体艺术 gogo| 18+在线观看网站| 亚洲精品日韩在线中文字幕 | 精品免费久久久久久久清纯| 国产久久久一区二区三区| 永久网站在线| 久久久精品94久久精品| 国产精品伦人一区二区| 久久久久免费精品人妻一区二区| 性欧美人与动物交配| 少妇的逼水好多| 91午夜精品亚洲一区二区三区| 两个人视频免费观看高清| 国产 一区 欧美 日韩| 久久热精品热| 两个人视频免费观看高清| 99热这里只有是精品50| 村上凉子中文字幕在线| 亚洲av免费高清在线观看| 欧美日韩综合久久久久久| 欧美在线一区亚洲| 白带黄色成豆腐渣| 免费搜索国产男女视频| 亚洲经典国产精华液单| 美女内射精品一级片tv| 国产精品1区2区在线观看.| av视频在线观看入口| 欧美+日韩+精品| 激情 狠狠 欧美| 国产在线男女| 日韩强制内射视频| 亚洲国产日韩欧美精品在线观看| 国产精品精品国产色婷婷| 少妇的逼水好多| 女生性感内裤真人,穿戴方法视频| 成人综合一区亚洲| 亚洲内射少妇av| 国内精品久久久久精免费| 亚州av有码| 一本精品99久久精品77| 99热只有精品国产| 日韩大尺度精品在线看网址| 五月玫瑰六月丁香| 黄色欧美视频在线观看| 国产国拍精品亚洲av在线观看| 亚洲av成人精品一区久久| av免费在线看不卡| 亚洲在线观看片| 免费不卡的大黄色大毛片视频在线观看 | 免费av不卡在线播放| 99久久无色码亚洲精品果冻| av天堂中文字幕网| 亚洲精品国产av成人精品 | 97热精品久久久久久| 国产亚洲精品综合一区在线观看| 久久精品国产亚洲av香蕉五月| 日韩高清综合在线| 麻豆成人午夜福利视频| 成年版毛片免费区| 国产一区二区三区在线臀色熟女| 又爽又黄无遮挡网站| 日韩一本色道免费dvd| 午夜福利在线观看吧| 久久久久久久久久成人| 国产精品三级大全| 十八禁国产超污无遮挡网站| 日韩中字成人| 99久国产av精品国产电影| 黄色一级大片看看| 欧美一区二区国产精品久久精品| 日本在线视频免费播放| 村上凉子中文字幕在线| 在现免费观看毛片| 国产精品亚洲一级av第二区| a级毛片a级免费在线| 亚洲在线自拍视频| 九九久久精品国产亚洲av麻豆| 成人鲁丝片一二三区免费| 悠悠久久av| 久久久久九九精品影院| 亚洲最大成人中文| 变态另类丝袜制服| av黄色大香蕉| 热99在线观看视频| 少妇人妻精品综合一区二区 | av专区在线播放| 久久精品夜夜夜夜夜久久蜜豆| 国产中年淑女户外野战色| av天堂中文字幕网| or卡值多少钱| 中文字幕久久专区| 国产精品国产三级国产av玫瑰| 人妻久久中文字幕网| 婷婷精品国产亚洲av在线| 午夜精品在线福利| 欧美区成人在线视频| 91在线精品国自产拍蜜月| 中文资源天堂在线| 国产一区亚洲一区在线观看| 成人亚洲精品av一区二区| 日韩一本色道免费dvd| 久久国内精品自在自线图片| 又黄又爽又免费观看的视频| 国产欧美日韩精品亚洲av| 欧洲精品卡2卡3卡4卡5卡区| 99国产极品粉嫩在线观看| 亚洲最大成人手机在线| 老熟妇乱子伦视频在线观看| 久久综合国产亚洲精品| 中文字幕久久专区| 色吧在线观看| 99精品在免费线老司机午夜| 露出奶头的视频| 成人永久免费在线观看视频| 一个人观看的视频www高清免费观看| 免费av不卡在线播放| 最近手机中文字幕大全| 久久热精品热| 欧美中文日本在线观看视频| 国产伦精品一区二区三区视频9| 亚洲天堂国产精品一区在线| 欧美精品国产亚洲| 赤兔流量卡办理| 俄罗斯特黄特色一大片| 大香蕉久久网| 亚洲精品国产av成人精品 | 韩国av在线不卡| 亚洲欧美日韩无卡精品| 色尼玛亚洲综合影院| 国产精品免费一区二区三区在线| 99久久精品一区二区三区| 欧美性猛交╳xxx乱大交人| 少妇熟女aⅴ在线视频| 亚洲五月天丁香| 成人特级黄色片久久久久久久| 久久午夜亚洲精品久久| 此物有八面人人有两片| 国产精品久久久久久久久免| 亚洲综合色惰| 日韩一区二区视频免费看| 我要看日韩黄色一级片| 成年版毛片免费区| 一本一本综合久久| 蜜臀久久99精品久久宅男| 中文字幕久久专区| 日本精品一区二区三区蜜桃| 精品久久久久久久久久免费视频| 综合色av麻豆| 99久久九九国产精品国产免费| 亚洲精品久久国产高清桃花| 国产高清视频在线播放一区| 成人鲁丝片一二三区免费| 久久亚洲精品不卡| 高清毛片免费看| 国产一区二区在线观看日韩| 麻豆av噜噜一区二区三区| 99国产极品粉嫩在线观看| 深夜a级毛片| 嫩草影院入口| 91狼人影院| 男女做爰动态图高潮gif福利片| 精品乱码久久久久久99久播| 夜夜夜夜夜久久久久| 三级国产精品欧美在线观看| 久久午夜福利片| 久久久久国产精品人妻aⅴ院| 我要看日韩黄色一级片| 美女被艹到高潮喷水动态| 国产精品三级大全| 天堂av国产一区二区熟女人妻| 国产成人福利小说| a级一级毛片免费在线观看| 女生性感内裤真人,穿戴方法视频| 成人美女网站在线观看视频| 久久久久久久久久黄片| 天堂影院成人在线观看| 丰满人妻一区二区三区视频av| 日本一本二区三区精品| 国产精品人妻久久久影院| 国产探花在线观看一区二区| 国产高清视频在线观看网站| 国产色婷婷99| 国产精品三级大全| 人人妻人人看人人澡| 久久久精品欧美日韩精品| 亚洲无线观看免费| 嫩草影院新地址| 又黄又爽又免费观看的视频| 亚洲五月天丁香| 亚洲人成网站在线播放欧美日韩| 国产亚洲av嫩草精品影院| 九九在线视频观看精品| 午夜福利视频1000在线观看| 夜夜看夜夜爽夜夜摸| 亚洲四区av| ponron亚洲| 一级黄片播放器| 午夜福利18| 欧美中文日本在线观看视频| 一a级毛片在线观看| 国内久久婷婷六月综合欲色啪| av免费在线看不卡| 亚洲av成人精品一区久久| 亚洲国产欧洲综合997久久,| 欧美最黄视频在线播放免费| 99在线人妻在线中文字幕| 免费一级毛片在线播放高清视频| 欧美性猛交黑人性爽| av在线亚洲专区| 嫩草影院新地址| 日韩在线高清观看一区二区三区| 欧美性猛交╳xxx乱大交人| 欧美高清成人免费视频www| 激情 狠狠 欧美| 久久亚洲国产成人精品v| 日韩成人av中文字幕在线观看 | av在线观看视频网站免费| 国产亚洲欧美98| 少妇被粗大猛烈的视频| 国产久久久一区二区三区| 色吧在线观看| 淫妇啪啪啪对白视频| 美女黄网站色视频| av黄色大香蕉| 九九久久精品国产亚洲av麻豆| 国产精品久久电影中文字幕| 久久这里只有精品中国| 亚洲美女搞黄在线观看 | 夜夜夜夜夜久久久久| 99国产极品粉嫩在线观看| 国产麻豆成人av免费视频| 久久鲁丝午夜福利片| 22中文网久久字幕| 亚洲五月天丁香| 人妻制服诱惑在线中文字幕| 免费观看人在逋| 在线播放无遮挡| 久久这里只有精品中国| 女人被狂操c到高潮| 村上凉子中文字幕在线| aaaaa片日本免费| 大型黄色视频在线免费观看| 国产精品一区www在线观看| 亚洲av五月六月丁香网| 狂野欧美激情性xxxx在线观看| 可以在线观看毛片的网站| 国产精品久久久久久精品电影| 可以在线观看的亚洲视频| 国产精品亚洲一级av第二区| 午夜福利在线观看吧| 波野结衣二区三区在线| 嫩草影院入口| 小说图片视频综合网站| 日韩欧美精品免费久久| 一级黄色大片毛片| 国产亚洲av嫩草精品影院| 日本黄色视频三级网站网址| 日韩高清综合在线| 国产精品一区二区性色av| av女优亚洲男人天堂| 日韩人妻高清精品专区| 最近2019中文字幕mv第一页| 日韩人妻高清精品专区| 非洲黑人性xxxx精品又粗又长| 亚洲精品日韩在线中文字幕 | av视频在线观看入口| 精品少妇黑人巨大在线播放 | 国产成人一区二区在线| av在线天堂中文字幕| 欧美+日韩+精品| 两个人视频免费观看高清| 伦理电影大哥的女人| 国产成人a∨麻豆精品| 成人亚洲欧美一区二区av| 插阴视频在线观看视频| 亚洲第一区二区三区不卡| 国内精品宾馆在线| 在线观看av片永久免费下载| 老司机影院成人| 国内少妇人妻偷人精品xxx网站| 麻豆成人午夜福利视频| 中文字幕av成人在线电影| 美女高潮的动态| 自拍偷自拍亚洲精品老妇| 如何舔出高潮| 日韩制服骚丝袜av| 中文在线观看免费www的网站| 在线免费观看的www视频| 天堂网av新在线| 亚洲国产欧美人成| 国产亚洲精品综合一区在线观看| 日韩欧美免费精品| 日韩精品中文字幕看吧| 色播亚洲综合网| 亚洲成人av在线免费| 午夜免费激情av| 国内少妇人妻偷人精品xxx网站| 日本撒尿小便嘘嘘汇集6| 美女大奶头视频| 国产乱人偷精品视频| 国产一区亚洲一区在线观看| 真人做人爱边吃奶动态| 99九九线精品视频在线观看视频| 国产探花极品一区二区| 欧美激情在线99| 夜夜看夜夜爽夜夜摸| 简卡轻食公司|