Processes of the displacement field change of the 2009 April 6 M_W6.3 L’Aquila earthquake using persistent scatterer and small baseline methods

Using a time series method that combines both the persistent scatterer and small baseline approaches, we analyzed 9 scenes Envisat ASAR data over the L＇Aquila earthquake, and obtained a Shocke＇s displacement field and its evolution processes. The results show that： （1） Envisat ASAR clearly detected the whole processes of displacement field of the L＇Aquila earthquake, and distinct variations at different stages of the displacement field. （2） Preseismic creep displacement → displacement mutation when faulting → constantly slowed down after the earthquake. （3） The area of the strongest deformation and ground rupture was a low-lying oval depression region to the southeast. Surface faulting within a zone of about 22 km× 14 km, with an orientation of 135°, occurred along the NW-striking and SW-dipping Paganica-S. Demetrio normal fault. （4） In analyzing an area of about 54 km x 59 km, bounded by north-south axis to the epicenter, the displacement field has significant characteristics of a watershed： westward of the epicenter shows uplift with maximum of 130 mm in line-of-sight （LOS）, and east of the epicenter was a region with 220 mm of maximum subsidence in the LOS, concentrating on the rupture zone, the majority of which formed in the course of faulting and subsequence.     

AUV移动探测下基于U-Net网络的本体噪声去除

在基于移动 AUV(自主水下机器人)平台的水下机动目标探测场景中,由于拖曳能力和探测孔径的限制,目标噪声极易淹没在本体噪声中。而且,本体噪声与目标噪声具有非常相似的频谱特性和倍频关系,进一步加重了目标噪声分析的难度。为降低本体噪声的影响、提高目标噪声的信噪比,开展了基于 U-Net 深度网络的水下混合噪声信号分离算法研究。通过仿真模型测试了算法在不同转速差、桨叶数差以及目标噪声信噪比条件下去除本体噪声的性能。实验结果初步表明：在目标信号信噪比不低于–10 dB 的条件下,算法可以对本体噪声进行有效去除。     

Genetic Types, Spatiotemporal Distribution of Ore Deposits and Sources of Ore-forming Materials in the Xuancheng Area, Anhui Province

In recent years, several large and medium-sized ore deposits have been discovered in the shallow cover of Xuancheng, Anhui Province, indicating that this area has a productive metallogenic geological background and may be a potential prospecting region. Based on systematic investigation, the geological and mineralization characteristics of porphyry Cu-Au deposits and skarn Cu-Mo-W deposits in this region have been summarized. Zircon U-Pb dating (LA-ICP-MS) of the Chating quartz-diorite porphyry and the Kunshan biotite pyroxene diorite yield concordia ages of 145.5 ± 2.1 Ma and 131.8 ± 2.1 Ma, respectively. Meanwhile, the Re-Os dating analyses for molybdenite from the Shizishan and Magushan skarn Cu-Mo deposits yielded 133.81 ± 0.86 Ma and 143.8 ± 1.4 Ma ages, respectively. When viewed in conjunction with previous studies, it is suggested that twostage (the early stage of 145–135 Ma and the late stage of 134–125 Ma) magmatism may have occurred during the Mesozoic in Xuancheng region. Early stage intrusive rocks are distributed along both sides of the Jiangnan deep fault (JDF).The intrusive rocks to the north of the JDF are mainly quartz-diorite porphyry and granodiorite (porphyry) rocks, related to porphyry Cu-Au deposits and skarn-type Cu-Mo-W deposits. These deposits belong to the first stage of the porphyry-skarn copper gold metallogenic belt of the Middle-Lower Yangtze Metallogenic Belt (MLYB), associated with the high potassium calc-alkaline intermediate-acid intrusions. The magmatic and ore-forming materials are mainly derived from the enriched lithospheric mantle. South of the JDF, the Magushan granodiorite is a representative intrusive rock of the first stage I-type granite, which hosts the Magushan Cu-Mo skarn deposit, similar to the W-Mo-Cu skarn deposits in the Eastern Segment of the Jiangnan Uplift Metallogenic Belt (ESJUB). The magmatic and metallogenic materials mainly came from the Neoproterozoic basement, with the possible participation of a small amount of mantle components. The late stage magmatism was dominated by volcanic rocks with a small amount of intrusive rocks, which were consistent with the limited volcanic-intrusive activities in the second stage of the MLYB. The H-O stable isotopes of ore deposits in the region indicate that the ore-forming hydrothermal fluids of the porphyry and skarn deposits were mostly of magmatic water for the ore-forming stage, the percentage of meteoric water obviously increasing during the late ore-forming stage. The ore-forming materials of the deposits are mainly from the deep magma with a few sedimentary wall rocks, according to the stable carbon isotopes of the carbonates in the ore deposits. Additionally, according to previous research, the molybdenite from the MLYB has a higher Re content than that of the ESJUB. The higher content of Re in the molybdenite from the Shizishan deposit is identical to that of MLYB rather than ESJUB, whereas Re characteristics in molybdenite of Magushan deposit are similar to that of ESJUB. The differences in Re characteristics indicate the different deep processes and ore-forming material sources (mainly mantle composition for the former and crustal materials for the latter) of these ore deposits on opposite sides of the JDF.     

遥感异常与地球化学指标间的映射关系模型探索

采用改进的遥感异常提取方法,以甘肃金川地区的LandSat 8遥感影像数据为基础,结合主成份分析方法及低通滤波后期处理,得到空间规律性较强的烃基及铁染异常;进而对测区的土壤地球化学取样分析数据,利用统计学方法寻找不同元素异常(或地球化学指标)的内在关联,并建立土壤地球化学指标比值与遥感异常之间的关系模型.继续构建出基于...