基于Earthworm的地震预警系统研究进展?以伊比利亚西南部为例          下载免费PDF全文

NúriaRomeu Petit  YolandaColom Puyané  JoséAntonio Jara Salvador  XavierGoula Suri?ach  TeresaSusagna Vidal  王林 《地震科学进展》2018,(11):12-25

本研究的主要目的是基于该区域现有的实时宽频带台站，研究地震预警系统（earthquake early warning system，EEWS）对潜在破坏性地震发出警告的可行性。研究区位于伊比利亚半岛（Iberian Peninsula）西南部的圣维森特角（Cape San Vicente，SV）和加的斯湾（Gulf of Cádiz，GC）。该区域历史地震有1755年里斯本（Lisbon）M_w8.5地震和1969年圣维森特角M_w7.8地震。本研究阐明了基于美国地质调查局（U.S. Geological Survey，USGS）的Earthworm工具，及由西班牙加泰罗尼亚地质制图研究所（Institut Cartogràfici Geològicde Catalunya，ICGC）进一步研究出的地震预警系统的设计、配置和产出结果。系统的主要功能是实时数据采集、处理（利用预先估算的峰值位移P_d和P波信号的卓越周期τ_c进行P波拾取、地震事件监测、地震震源定位和震级估算）、数据归档和地震预警发布。系统在完成一些模拟实验并获得最佳配置后进行运行。在运行的第一年内，该区域发生了一次有感地震。与国家地理研究所（Instituto Geográfico Nacional，IGN）地震目录相比较，定位和震级结果都相当好。对于大部分区域的预警时间都能达到几十秒，对于葡萄牙和西班牙南部沿海大部分区域来说，足以减轻由GC和SV地震所带来的损害。此系统的初步结果表明，该系统能可靠地、有效地用于伊比利亚西南部地区的可能性。   相似文献   

Morphological and molecular evidence supports the first occurrence of two fishes,Siganus sutor(Valenciennes, 1835)and Seriolina nigrofasciata(Rüppell, 1829)(Actinopterygii:Perciformes), from marine waters of Odisha coast,Bay of Bengal,India     

Barik Tapan K.  Swain Surya N.  Sahu Bijayalaxmi  Tripathy Bibarani  Acharya Usha R. 《海洋学报(英文版)》2020,39(6):26-35

Marine ecosystems provide a wide variety of diverse habitats that frequently promote migration and ecological adaptation. The extent to which the geographic distribution of marine organism has reshaped by human activities remains underappreciated. The limitations intrinsic to morphology-based identification systems have engendered an urgent need for reliable genetic methods that enable the unequivocal recognition of fish species,particularly those that are prone to overexploitation and/or market substitution. In the present study, however, an attempt has been taken to identify two locally adapted fish species, Siganus sutor(Valenciennes, 1835) and Seriolina nigrofasciata(Rüppell, 1829) of order Perciformes, which happens to be the first record in Odisha coast,Bay of Bengal. The diagnostic characteristics of Siganus sutor are: dorsal fin XIII-10, anal fin VII-9, pectoral fin 15,pelvic fin II-3, while that of Seriolina nigrofasciata dorsal fin VI-I-35, anal fin I-17, pectoral fin 16, pelvic fin 5. All COI barcodes generated in this study were matched with reference sequences of expected species, according to morphological identification. Bayesian and likelihood phylogenetic trees were drawn based on DNA barcodes and all the specimens clustered in agreement with their taxonomic classification at the species level. The phylogeographic studies based on haplotype network and migration rates suggest that both the species were not panmitic and the high-frequency population distribution indicates successful migration. The result of this study provides an important validation of the use of DNA barcode sequences for monitoring species diversity and changes within a complex marine ecosystem.  相似文献   

Application of Optically Stimulated Luminescence Technique in Exploring a Concealed Sandstone-type Uranium Deposit     

KANG Huan  CHEN Yuelong  XUE Guoliang  ZHAO Junxiang  ZHANG N  ZHANG Yangyang 《《地质学报》英文版》2022,96(2):571-581

Identifying ore-induced geochemical anomalies at the surface that indicate concealed deposits in buried areas remains a significant challenge in geochemical exploration. In this study, in order to trace the source of the geochemical anomalies, systematic luminescence intensity analyses were conducted on quartz grains from the Quaternary regolith at the Hadatu sandstone-type uranium deposit in the Erenhot Basin. The optically stimulated luminescence (OSL) ages were much older than the depositional ages of the Quaternary regolith. Moreover, quartz OSL ages were closely related to both borehole grades and sampling depths. Thus, the abnormal mineral OSL ages from near-surface sediments were ultimately controlled by the sandstone-type uranium deposits. This is identical to the rapid changes of quartz OSL ages (0.063 ka/cm) and equivalent doses (0.19 Gy/cm) with depths in a given sampling site. The instantaneous soil radon concentration was positively correlated with the quartz OSL apparent age, indicating their ore-induced origin and, as a result, their effectiveness in the exploration of concealed uranium deposits. Other parameters, including mobile-state uranium and 210Po contents, were poorly correlated with quartz OSL ages and therefore should only be used with caution for geochemical exploration. This is the first time an attempt has been made to discriminate the ore-induced sources for different surface anomaly parameters, including instantaneous soil radon, mobile-state uranium and 210Po contents for concealed sandstone-type uranium deposits.  相似文献   

Mantle Transects in Africa According to Data of Mantle Xenocrysts and Diamond Inclusions     

Igor V. ASHCHEPKOV  Vladimir N. ZINCHENKO  Alexandr S. IVANOV 《《地质学报》英文版》2021,95(Z1):15-17

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尼泊尔低喜马拉雅推覆带油源对比及油气成藏     

杨平  谭富文  施美凤  王正和  李忠雄  占王忠  Sudhir RAJAURE  Ganesh N.TRIPATHI 《地质学报》2021,95(11):3426-3441

尼泊尔低喜马拉雅推覆带油气苗来源不清极大地影响了该区油气勘探.在地质-地球物理综合调查的基础上,利用油气地球化学、碳同位素及生烃史模拟对尼泊尔代莱克地区油源和成藏过程进行了研究.结果表明:①尼泊尔代莱克地区油苗产于Padukasthan断裂,可分两期,第一期呈含油断层泥产出,氯仿沥青"A"为149～231 μg/g,RR.为0.81％,氯仿沥青"A"的δ13C相对较重(-26.24‰～-27.10‰),族组分具有正碳同位素序列,发黄绿色荧光,为典型的低熟煤成油,第二期呈液态油产出并遭受微生物降解,金刚烷IMD指数为0.33～0.45,R.为1.24％～1.53％,3,4-DMD含量46％～47％,全油δ13C为-29.50‰～-29.45‰,族组分碳同位素趋于一致,发蓝色荧光,为海相成因高熟油;②第一期油来源于Surkhet群的Melpani组和Gondwana群煤系烃源岩,为Ⅲ型有机质低熟阶段的产物,第二期来源于Surkhet群的Swat组浅海陆棚相黑色页岩,为Ⅱ1型有机质生油高峰的产物,两期油与Lakharpata群过成熟黑色泥岩和Siwalik群未熟泥岩没有亲缘关系;③尼泊尔低喜马拉雅推覆带具有"多源多期、推覆增熟、砂体控储、披覆控聚"的油气成藏模式,油气成藏过程可划分为沉积浅埋、构造圈闭形成、深埋油藏形成、气藏形成和晚期改造定型5个演化阶段;④尼泊尔低喜马拉雅推覆有利于Gondwana群、Surkhet群深埋增温、持续快速生烃和晚期成藏,对比邻区巴基斯坦的含油气盆地,尼泊尔低喜马拉雅推覆带及相邻类似地区具备良好的油气成藏条件.  相似文献   

Glacier reconstruction of La Covacha Massif in Sierra de Gredos(central Spain) during the Last Glacial Maximum     

Néstor CAMPOS  David PALACIOS  Luis M.TANARRO 《山地科学学报》2019,(6)

A paleoglacier reconstruction during the Last Glacial Maximum(LGM) is presented for a high mountain area of La Covacha massif in Sierra de Gredos(Iberian Central System) in central Spain. The moraines that, according with the previous literature, had formed during the global LGM, were mapped through photo interpretation of digital aerial photographs and 3D images and detailed field surveys. The topography of the paleoglaciers was estimated using a simple steady-state model that assumed a perfectly plastic ice rheology, reconstructing the theoretical ice profiles and obtaining the ice thickness of the glaciers during the LGM. The reconstruction of the glaciers was carried out using automated and semi-automated physically-based models, obtaining more realistic results with semi-automated models. According to our study, the paleoglaciers in the study area covered an area of 34.79 km~2 during the global LGM, with a maximum ice thickness of 366 meters in La Vega gorge, a total volume of 34.25 × 108 m~3 and a mean paleoELA of 1932 meters. Most of the ice(～82%) was in paleoglaciers facing north, and the rest was in paleoglaciers with other orientations. This emphasizes the importance of orientation in relation to glacier dynamics and ice accumulation. The results obtained in the calculation of paleoELAs during the global LGM in Gredos are average compared to the Iberian mountains of the Northwest where the values were much lower, and with respect to those of the Southwest, much higher. This demonstrates the importance of the exposure of Mediterranean mountains to the humidity sources coming from the NW during the global LGM, as is the case at present.  相似文献   

Chromite in the Mantle Section of the Oman Ophiolite: Implications for the Tectonic Evolution of the Oman Ophiolite     

SAVELYEVA G.N.  BATANOVA V.G. 《《地质学报》英文版》2015,89(Z2):77-78

<正>Structure and composition of the Uralian ophiolites reflect a large spectrum of geodynamic environment of their creation during Paleozoic time:from mid-ocean ridge,rift zone in continental margin,and suprasubduction spreading zone(SSZ)with resultant lherzolite or harzburgite ophiolite type(LOT and HOT).Residual  相似文献   

Mesoscale surface circulation and variability of Southern Indian Ocean derived by combining satellite altimetry and drifter observations   总被引：1，自引：1，他引：0  

BENNY N. Peter  SHENBAKAVALLI Ranjan  MAZLAN Hashim  MOHD Nadzri Re  MOHD Razali Mahmud 《海洋学报(英文版)》2015,34(9):12-22

High resoultion Eulerian mean velocity field has been derived by combining the satellite tracked surface drifter data with satellite altimetry and ocean surface winds. The drifter data used in this study includes Argos and surface drifter data from Global Drifter Program. Maps of Sea Level Anomaly(MSLA) weekly files with a resolution of(1/3)° in both Latitude and Longitude for the period 1993–2012 have been used. The Ekman current is computed using ocean surface mean wind fields from scatterometers onboard ERS 1/2,Quikscat and ASCAT. The derived mean velocity field exhibits the broad flow of Antarctic Circumpolar Current with speeds up to 0.6 m/s.Anomalous field is quite significant in the western part between 20° and 40°E and in the eastern part between 80°E and 100°E with velocity anomaly up to 0.3 m/s. The estimated mean flow pattern well agrees with the dynamic topography derived from in-situ observations. Also,the derived velocity field is consistent with the in-situ ADCP current measurements. Eddy kinetic energy illustrates an increasing trend during 1993–2008 and is in phase coherence with the Southern Annular Mode by three month lag. Periodic modulations are found in the eddy kinetic energy due the low frequency Antarctic Circumpolar Wave propagation.  相似文献   

Modelling of sediment movement in the surf and swash zones     

TOKPOHOZIN N. B.  KOUNOUHEWA B.  AVOSSEVOU G. Y. H.  HOUEKPOHEHAM A.  AWANOU C. N. 《海洋学报(英文版)》2015,34(2):137-142

Under the action of marine currents, non-cohesive sediments evolve by bed-load, by saltation or suspension depending on their granulometry. Several authors have considered that the movement of sediment...  相似文献   

2012年夏季楚科奇海浮游动物垂直迁移及上升流对其生物量的影响     

WANG Huiwu  CHEN Hongxi  XUE Liang  LIU N  LIU Yanliang 《海洋学报(英文版)》2015,34(5):68-74

The diel vertical migration(DVM) of zooplankton and the influence of upwelling on zooplankton biomass were examined using water column data of current velocity and mean volume backscattering strength(MVBS)collected by moored acoustic Doppler current profilers(ADCPs) deployed in the southeastern Chukchi Sea during the 5th Chinese National Arctic Research Expedition(CHINARE) in summer 2012, combined with the satellite observational data such as sea surface temperature(SST), wind, and chlorophyll a(Chl a). Hourly acoustic data were continuously collected for 49-d in the mooring site. Spectral analysis indicated that there were different migrating patterns of zooplankton, even though precisely classifying the zooplankton taxa was not available. The prevailing 24-h cycle corresponded to the normal DVM with zooplankton swimming upwards at sunrise and returning to deep waters at sunset. There was a clear DVM in the upper 17 m of the water column during the period with distinct day-night cycles, and no active DVM throughout the water column when the sun above the horizon(polar day), suggesting that light intensity was the trigger for DVM. Also there was a second migrating pattern with 12-h cycle. The upwelling event occurring in the northwest of Alaskan coastal area had important influence on zooplankton biomass at the mooring site. During the upwelling, the SST close to the mooring site dropped significantly from maximal 6.35°C to minimal 1.31°C within five days. Simultaneously, there was a rapid increase in the MVBS and Chl a level, suggesting the aggregation of zooplankton related to upwelling.  相似文献