Constraint on the focal mechanism of the 2011 Tohoku earthquake from the radial modes

Different from other normal modes of the Earth’s free oscillation that depend on all the six components(M_(rr),M_(tt),M_(pp),M_(rt),M_(rp),and M_(tp))of the centroid moment tensor,the amplitudes of the radial modes depend on the M_(rr)component(e.g.,scalar moment(M_(0)),dip(δ),and slip(λ))and hypocenter depth of the focal mechanism,and hence can be easily used to constrain these parameters of the focal mechanism.In this study,we use the superconducting gravimeter(SG)records after the 2011 Tohoku earthquake to analyze the radial modes_(0)S_(0)and_(1)S_(0).Based on the solutions of the focal mechanism provided by the GCMT and USGS,we can obtain the theoretical amplitudes of these two radial modes.Comparing the theoretical amplitudes with the observation amplitudes,it is found that there are obvious differences between the former and the latter,which means that the GCMT and USGS focal mechanisms cannot well represent the real focal mechanism of the 2011 event.Taking the GCMT solution as a reference and changing the depth and the three parameters of the M_(rr)moment,the scalar moment(M_(0))and the dip(δ)have significant influences,but the effects of the slip(λ)and the depth are minor.After comparisons,we provide a new constraint(M_(0)=5.8±0.09×10^(22)N·m,δ=10.1±0.08°,λ=88°,and depth=20 km)for the focal mechanism of the 2011 event.In addition,we further determine the center frequency(1.631567±2.6e^(-6)mHz)and quality factor(2046.4±50.1)of the_(1)S_(0)mode.

Unexpected focal fluorodeoxyglucose uptake in main organs;pass through or pass by?

Since the inception of fluorine-18 fluorodeoxyglucose(F-18 FDG),positron emission tomography/computed tomography(PET/CT)utilizing F-18 FDG has become widely accepted as a valuable imaging modality in the field of oncology,with global prevalence in clinical practice.Given that a single Torso PET/CT scan encompasses the anatomical region from the skull base to the upper thigh,the detection of incidental abnormal focal hypermetabolism in areas of limited clinical interest is both feasible and not uncommon.Numerous investigations have been undertaken to delineate the distinctive features of these findings,yet the outcomes have proven inconclusive.The incongruent results of these studies present a challenge for physicians,leaving them uncertain about the appropriate course of action.This article provides a succinct overview of the characteristics of fluorodeoxyglucose,followed by a comprehensive discussion of the imaging findings and clinical significance associated with incidental focal abnormal F-18 FDG activity in several representative organs.In conclusion,while the prevalence of unrecognized malignancy varies across organs,malignancies account for a substantial proportion,ranging from approximately one-third to over half,of incidental focal uptake.In light of these rates,physicians are urged to exercise vigilance in not disregarding unexpected uptake,facilitating more assured clinical decisions,and advocating for further active evaluation.

Design and fabrication of compound varifocal lens driven by polydimethylsiloxane film elastic deformation

A compound varifocal lens based on electromagnetic drive technology is designed and fabricated, where the polydimethylsiloxane(PDMS) film acts as a driving component, while the PDMS biconvex lens and the plane-concave lens form a coaxial compound lens system. The plane-concave lens equipped with driving coils is installed directly above the PDMS lens surrounded by the annular magnet. When different currents are applied, the annular magnet moves up and down, driving the PDMS film to undergo elastic deformation, and then resulting in longitudinal movement of the PDMS lens. The position change of the PDMS lens changes the focal length of the compound lens system. To verify the feasibility and practicability of this design, a prototype of our compound lens system is fabricated in experiment. Our proposed compound lens shows that its zoom ability reaches 9.28 mm when the current ranges from -0.20 A to 0.21 A.

Clinicopathological features and medium-term outcomes of histologic variants of primary focal segmental glomerulosclerosis in adults:A retrospective study

BACKGROUND The Columbia classification identified five histological variants of focal segmental glomerulosclerosis(FSGS).The prognostic significance of these variants remains controversial.AIM To evaluate the relative frequency,clinicopathologic characteristics,and medium-term outcomes of FSGS variants at a single center in Pakistan.METHODS This retrospective study was conducted at the Department of Nephrology,Sindh Institute of Urology and Transplantation,Karachi,Pakistan on all consecutive adults(≥16 years)with biopsy-proven primary FSGS from January 1995 to December 2017.Studied subjects were treated with steroids as a first-line therapy.The response rates,doubling of serum creatinine,and kidney failure(KF)with replacement therapy were compared between histological variants using ANOVA or Kruskal Wallis,and Chi-square tests as appropriate.Data were analyzed by SPSS version 22.0.P-value≤0.05 was considered significant.RESULTS A total of 401 patients were diagnosed with primary FSGS during the study period.Among these,352(87.7%)had a designated histological variant.The not otherwise specified(NOS)variant was the commonest,being found in 185(53.9%)patients,followed by the tip variant in 100(29.1%)patients.Collapsing(COL),cellular(CEL),and perihilar(PHI)variants were seen in 58(16.9%),6(1.5%),and 3(0.7%)patients,respectively.CEL and PHI variants were excluded from further analysis due to small patient numbers.The mean follow-up period was 36.5±29.2 months.Regarding response rates of variants,patients with TIP lesions achieved remission more frequently(59.5%)than patients with NOS(41.8%)and COL(24.52%)variants(P<0.001).The hazard ratio of complete response among patients with the COL variant was 0.163[95%confidence interval(CI):0.039-0.67]as compared to patients with NOS.The TIP variant showed a hazard ratio of 2.5(95%CI:1.61-3.89)for complete remission compared to the NOS variant.Overall,progressive KF was observed more frequently in patients with the COL variant,43.4%(P<0.001).Among these,24.53%of patients required kidney replacement therapy(P<0.001).The hazard ratio of doubling of serum creatinine among patients with the COL variant was 14.57(95%CI:1.87-113.49)as compared to patients with the TIP variant.CONCLUSION In conclusion,histological variants of FSGS are predictive of response to treatment with immunosuppressants and progressive KF in adults in our setup.

Does the intracoronary pressure differ according to two types(diffuse or focal)of coronary spasm?

BACKGROUND Several reports show that two types of coronary vasospasm(diffuse and focal spasm)are associated with the severity or prognosis of coronary spasm in patients with vasospastic angina(VSA).It is unclear whether intracoronary pressure differs between the two spasm types.AIM To investigate such relationships using a pressure wire during the spasm provocation test(SPT)in patients with VSA.METHODS Eighty-seven patients with VSA(average age:67 years;50 men,37 women)underwent SPT.During the SPT,a pressure wire was advanced into the distal portion of the right coronary artery and left anterior descending coronary artery,and the ratio of the intracoronary pressure to the aortic pressure(Pd/Pa)was continuously monitored.An SPT was performed using acetylcholine(ACh),and the presence of coronary spasm was defined as the presence of>90%arterial narrowing in response to an ACh infusion,with the usual chest symptoms and/or ischemic ECG changes.Focal spasm was defined as total or subtotal spasm within one segment of the AHA classification,while diffuse spasm was defined as>90%spasm with two or more segments.RESULTS Among 87 patients,the frequencies of metabolic syndrome and having coronary atherosclerosis were higher in the focal group(n=33)than in the diffuse spasm group(n=54,P<0.05).In the vessel analyses,in these 134 spastic segments,diffuse and focal spasms were detected in 100 and 34 vessels,respectively.The Pd/Pa at baseline was similar in both groups(diffuse:0.96±0.05,focal:0.95±0.05,P=0.35);however,the Pd/Pa during coronary spasm was lower in focal spastic vessels(0.66±0.20)than in diffuse spastic vessels(0.76±0.11,P<0.01),and the reduction in Pd/Pa during an SPT was also lower in focal spastic vessels(-0.29±0.20)than in diffuse spastic vessels(-0.18±0.11,P<0.01).The presence of focal spasm was a significant factor responsible for reduction in Pd/Pa during SPT.CONCLUSION These findings suggest that focal spasm may be more severe than diffuse spasm,judging from the intracoronary pressure during coronary spasm.

Role of endoscopic ultrasound and endoscopic ultrasound-guided tissue acquisition in diagnosing hepatic focal lesions

BACKGROUND Endoscopic ultrasonography(EUS)has become an established method in diagnostic and therapeutic procedures in gastroenterology;however,it has recently gained a growing role in hepatology.AIM To evaluate the role of EUS features,strain elastography(SE),and EUS-tissue acquisition in diagnosing hepatic focal lesions(HFLs)that could affect further management.METHODS This cross-sectional study included 215 patients with pancreatic,biliary,or gastrointestinal malignancies referred for EUS examination.HFLs were identified in 43 patients(20%),and EUSguided tissue acquisition was performed from these lesions.RESULTS EUS features were highly sensitive(100%)but much less specific(57%)in diagnosing HFLs;the overall accuracy was 94%.Real-time elastography was also very sensitive(97%)but less specific(67%)in diagnosing HFLs;however,the overall accuracy was 92%.EUS tissue acquisition was extremely sensitive(100%)and specific(100%),with a 100%overall diagnostic accuracy.CONCLUSION The diagnostic utility of EUS-guided tissue acquisition was extremely accurate in diagnosing HFLs.EUS characteristics and real-time SE accurately predicted the histological diagnosis of both benign and malignant HFLs.

Focal ablation therapy presents promising results for selectively localized prostate cancer patients

Due to its lower risk of consequences when compared to a radical approach, focal treatment is a viable and minimally invasive option for treating specific localized prostate cancer. Although several recent good nonrandomized trials have suggested that focused therapy may be an alternative choice for some patients, additional high-quality evidence is needed before it can be made widely available as a conventional treatment. As a result, we have summarized the most recent findings from the 38th Annual European Association of Urology Congress, one of the most renowned annual conferences in the area of urology, regarding focal ablation therapy for patients with localized prostate cancer. Additionally, we also provided clinical trials in progress for researchers to better understand the current research status of this field.

基于优化Focal-XGBoost的变压器状态声振识别模型

受数据样本难以区分和数据平衡性不佳影响,采用声振信号的变压器状态识别模型往往准确率低下。针对这一问题,引入了Focal损失,根据样本训练过程的准确度动态反馈权重,从而构成了Focal-XGBoost优化模型。先通过一组贴合变压器频谱的滤波器充分提取声振信号有效信息,再作XGBoost-PCA筛选降低样本维度。然后采用Focal损失优化原模型中的Softmax目标函数形成Focal-XGBoost模型,并在输入上述样本后根据准确率波动作Focal的超参数优化,进而输出变压器状态识别结果。10 kV和110 kV变压器的试验结果表明,相较传统SVM、KNN等学习模型,Focal-XGBoost减少了XGBoost测试样本中难分样本的误分量44.7%,从而使模型识别准确率更高;此外,非均匀提取在平均精度损失低于0.5%的基础上压缩50%样本空间,进一步降低了模型训练成本。

Focal Segmantal Glomerulosclerosis: Epidemiological, Clinico-Biological, Pathological, Etiological, Therapeutic and Evolutionary Profiles in Dakar

Introduction: Focal Segmental Glomerulosclerosis (FSGS) corresponds to a clinicopathological syndrome, manifested by generally abundant proteinuria associated with hyaline deposits on part of certain glomeruli and sparing other glomeruli, with effacement of the pedicels. The general objective was to determine the prevalence of FSGS, and to give its profiles;epidemiological, clinical, biological, pathological, etiological, therapeutic and evolutionary of FSGS. Materials and Methods: This is a retrospective analytical study over a period of six years extending from January 1, 2010 to December 31, 2015 patients aged 16 or over who were hospitalized or received consultations during the study period for primary or secondary segmental and focal hyalinosis. Patients whose records were incomplete or unusable were not included in the study. Results: We have 16.54% with 158 cases of FSGS out of 6945 patients received and/or hospitalized. Of the 955 kidney biopsies distributed, the incidences of HSF were;10.15%;14.04%;15%;17.64%;20.11%;19.58% respectively in 2010;2011;2012;2013;2014 and 2015, i.e. an annual increase of around 1.25%. Renal-type edemas were found in 93.3%, the first reason for hospitalization. And ninety-six people had impaired kidney function, or 61%. The average of 24-hour proteinuria was 6.4 ± 3.69 g/24 hours. The extremes were 0.37 and 18.50 g/24h. Patients had nephrotic proteinuria in 84.86%. Non-specific FSGS or NOS (Not Other Specificities) was found in 62 cases or 39.24%, collapsing FSGS in 48 cases or 30.40%. FSGS with found causes was associated with fibrosis in 5/35 cases. Collapsing FSGSs followed by NOS FSGSs were the most corticosteroid-resistant. The evolution of the FSGS reveals that every 8 months the proteinuria decreases by half. Conclusion: Segmental and focal hyalinosis requires histological confirmation and the epidemiological, clinico-biological, etiological, therapeutic and evolutionary profiles depend on the histological (pathological) type. Other works on the risk factors for occurrence and the contribution of electron microscopy in the primary and secondary diagnosis of segmental and focal hyalinosis are desired.

Adult focalβ-cell nesidioblastosis:A case report

BACKGROUND Nesidioblastosis usually refers to a series of clinical manifestations caused by the proliferation ofβ-cells in pancreatic islets,and these clinical manifestations are hyperinsulinemia and persistent hypoglycemia.According to the size of the lesion,nesidioblastosis is divided into focal nesidioblastosis,diffuse nesidioblastosis and atypical nesidioblastosis,and its pathogenesis is still unclear.Nesidioblastosis is mainly seen in infants and rarely reported in adults,especially focal nesidioblastosis,which is difficult to distinguish from insulinoma.CASE SUMMARY We report a case of adult focalβ-cell nesidioblastosis in which the preoperative diagnosis was insulinoma.The patient was a 48-year-old male who suffered from repeated morning and fasting palpitations,sweating,and severe disturbance of consciousness for 5 years.His blood glucose was found to be as low as 1.79 mmol/L during an attack.However,abdominal computed tomography showed no abnormalities.Magnetic resonance imaging and endoscopic ultrasonography demonstrated a nodular mass in the head of the pancreas,combined with hyperinsulinemia and high serum C-peptide.The patient was diagnosed with insulinoma and underwent Beger surgery;however,the postoperative pathological results showed nesidioblastosis.CONCLUSION Although surgical resection is the preferred option for nesidioblastosis,some cases can be treated non-surgically.In order to increase clinicians’understanding of nesidioblastosis,it is necessary to review the pathogenesis,diagnosis and treatment of this disease.

Synergism of calycosin and bone marrow-derived mesenchymal stem cells to combat podocyte apoptosis to alleviate adriamycininduced focal segmental glomerulosclerosis

BACKGROUND Bone marrow-derived mesenchymal stem cells(MSCs)show podocyte-protective effects in chronic kidney disease.Calycosin(CA),a phytoestrogen,is isolated from Astragalus membranaceus with a kidney-tonifying effect.CA preconditioning enhances the protective effect of MSCs against renal fibrosis in mice with unilateral ureteral occlusion.However,the protective effect and underlying mechanism of CA-pretreated MSCs(MSCsCA)on podocytes in adriamycin(ADR)-induced focal segmental glomerulosclerosis(FSGS)mice remain unclear.AIM To investigate whether CA enhances the role of MSCs in protecting against podocyte injury induced by ADR and the possible mechanism involved.METHODS ADR was used to induce FSGS in mice,and MSCs,CA,or MSCsCA were administered to mice.Their protective effect and possible mechanism of action on podocytes were observed by Western blot,immunohistochemistry,immunofluorescence,and real-time polymerase chain reaction.In vitro,ADR was used to stimulate mouse podocytes(MPC5)to induce injury,and the supernatants from MSC-,CA-,or MSCsCA-treated cells were collected to observe their protective effects on podocytes.Subsequently,the apoptosis of podocytes was detected in vivo and in vitro by Western blot,TUNEL assay,and immunofluorescence.Overexpression of Smad3,which is involved in apoptosis,was then induced to evaluate whether the MSCsCA-mediated podocyte protective effect is associated with Smad3 inhibition in MPC5 cells.RESULTS CA-pretreated MSCs enhanced the protective effect of MSCs against podocyte injury and the ability to inhibit podocyte apoptosis in ADR-induced FSGS mice and MPC5 cells.Expression of p-Smad3 was upregulated in mice with ADR-induced FSGS and MPC5 cells,which was reversed by MSCCA treatment more significantly than by MSCs or CA alone.When Smad3 was overexpressed in MPC5 cells,MSCsCA could not fulfill their potential to inhibit podocyte apoptosis.CONCLUSION MSCsCA enhance the protection of MSCs against ADR-induced podocyte apoptosis.The underlying mechanism may be related to MSCsCA-targeted inhibition of p-Smad3 in podocytes.

Study on the effect of focal position change on the expansion velocity and propagation mechanism of plasma generated by millisecond pulsed laser-induced fused silica

In this work, by controlling the positional relationship between the target and the focal point, the surface damage, shock wave phenomenon and propagation mechanism involved in the plasma generation of fused silica by millisecond pulsed laser irradiation at different focal positions were studied. Laser energy is an important experimental variable. The dynamic process of plasma was detected by optical shadow method, and the influence of surface film damage on plasma propagation and the propagation mechanism at different focal positions were discussed. The study found that the plasma induced by the pulsed laser at the focus position within 0–20 μs exploded, the micro-droplets formed around 20 μs. At the same time, a shock wave is formed by the compressed air, the micro-droplets are compressed under the action of the shock wave recoil pressure, and the micro-droplets channel phenomenon is observed in the micro-droplets. The peak velocities of plasma and combustion wave appear earlier in the pre-focus position than in the post-focus position. This research provides a reference for the field of laser processing using fused silica as the substrate.

Focal mechanism of Luding M 6.8 earthquake, September 2022 and analysis of the loading role of the tectonic stress on the seismogenic fault

To reveal the seismogenic mechanism of the Luding earthquake, we employed the 118 China Seismic Network stations to collect the P-wave polarity data from each station, which was then used in the P-wave first motion approach to calculate the focal mechanism solution of the M6.8 Luding earthquake that occurred on September 5,2022. We have also studied the loading effect of tectonic stress on the Luding earthquake fault based on the stress field data for the research area. The results indicate that this earthquake was a strike-slip type, the nodal plane I:strike 167°, dip angle 78°, slip angle 2°;Nodal plane II: strike 77°, dip angle 88°, slip angle 168°. The two fault planes’ instability coefficients of the Luding earthquake are examined considering the region’s background stress field’s condition. The nodal plane I in the Moho circle is discovered to practically coincide with the Coulomb failure line and the tangent point of the Moho circle, indicating that this nodal plane has a high instability coefficient compared to the nodal plane II. The conclusion is that the nodal plane I has a higher likelihood of being the seismogenic fault plane, which is congruent with the seismogenic fault plane suggested by the aftershock distribution, the earthquake radiation energy distribution of a single station, and seismic intensity distribution.The Luding earthquake’s focal mechanism is highly like the theoretical focal mechanism of the fault situated at the location where the Coulomb failure line intersects the Mohr circle, demonstrating that background stress is what caused the earthquake. The substantial fault instability and similarity between the solved and theoretical focal mechanisms make it easier to comprehend the loading effect of tectonic stress on the Luding earthquake fault.

Broadband and wide-angle plane focal surface Luneburg lens

The energy crisis has aroused widespread concern, and the reform of energy structure is imminent. In the future,the energy structure will be dominated by the solar energy and other renewable energy sources. The solar concentrating technology as a promising method has been widely studied for collecting solar energy. However, the previous solar concentrating technologies suffer from some drawbacks, such as low focusing efficiency and large concentrating size. The Luneburg lens with highly efficient aberration-free focusing provides a new route for solar/energy concentrator. In this work, we designed a plane focal surface Luneburg lens(PFSLL) by transformation optics(TO). The PFSLL provides a relatively high focusing efficiency and concentration ratio of collection of energy. At the same time, it circumvents the disadvantage of curve surface of the classical Luneburg lens in device integration. Based on the reciprocity of electromagnetic waves, the PFSLL can also be applied to the antenna field to achieve broadband wide-angle scanning and highly directional radiation.

融合Focal Loss与典型卷积神经网络结构的水稻病害图像分类

快速高效地识别水稻病害的种类并及时采取有效的防治措施对避免水稻减产具有重要意义,为解决人工识别水稻病害效率低、识别精度不高、深度学习样本不平衡导致识别准确率不高等问题,融合Focal Loss与4种典型卷积神经网络结构对7种水稻病害进行分类识别。利用TensorFlow的Keras深度学习框架搭建卷积神经网络的图像识别分类系统,使用Focal Loss损失函数解决数据集不平衡导致识别准确率低的问题,采用ResNet50、ResNet101、MobileNetV2、VGG16作为特征提取骨干,对7种水稻病害进行识别。通过imgaug库增强数据,将13543张水稻病害图像按照9∶1的比例划分为训练集和验证集并参与训练模型,将1404张水稻病害图像作为测试集来验证模型的准确性。结果表明,所搭建的数据集中ResNet50、ResNet101、MobileNetV2、VGG16的识别准确率分别为98.06%、94.26%、92.47%、97.83%。可见,在融合Focal Loss损失函数的情况下,ResNet50作为特征提取骨干训练出的模型在水稻病害图像分类中拥有最高的准确率,该成果可在实际生产中实现水稻病害的自动分类识别,有助于水稻病害的防治工作。

Focal lymphoblastic transformation of chronic myelogenous leukemia develops into erythroid leukemia:A case report

BACKGROUND We present a case of focal lymphoblastic transformation to erythroid leukemia following acute myeloblastic transformation in a patient with chronic myelogenous leukemia(CML)and discuss its mechanism of occurrence and development.CASE SUMMARY The presence of the Philadelphia(Ph)chromosome was identified through karyotype analysis,while the BCR-ABL fusion gene was detected using quantitative real-time polymerase chain reaction of the peripheral blood sample.Fluorescence in situ hybridization was used to detect the expression of the BCRABL gene in the lymphoma.Antigen expression and gene mutations in the primitive cells were detected by flow cytometry.The analysis confirmed the presence of CML along with focal lymphoblastic transformation to erythroid leukemia.Additionally,the patient was found to have secondary erythroid leukemia,along with multiple new gene mutations and abnormalities in complex karyotypes of chromosomes.CONCLUSION Our findings suggest a possible molecular basis for the focal lymphoblastic transformation secondary to myeloblastic transformation in patients with CML.

基于自适应空间特征增强的多视图深度估计

为了提高多视图深度估计结果精度,提出一种基于自适应空间特征增强的多视图深度估计算法。设计了由改进后的特征金字塔网络(feature pyramid network,FPN)和自适应空间特征增强(adaptive space feature enhancement,ASFE)组成的多尺度特征提取模块,获取到具有全局上下文信息和位置信息的多尺度特征图像。通过残差学习网络对深度图进行优化,防止多次卷积操作出现重建边缘模糊的问题。通过分类的思想构建focal loss函数增强网络模型的判断能力。由实验结果可知,该算法在DTU(technical university of denmark)数据集上和CasMVSNet(Cascade MVSNet)算法相比,在整体精度误差、运行时间、显存资源占用上分别降低了14.08%、72.15%、4.62%。在Tanks and Temples数据集整体评价指标Mean上该模型优于其他算法,证明提出的基于自适应空间特征增强的多视图深度估计算法的有效性。

基于改进YOLOv5s的海下垃圾检测算法

为了提升海下垃圾检测精度,降低漏检频率,提出了一种基于改进YOLOv5s的检测算法。该算法添加了ECA模块来关注感兴趣区域,构造了四级多尺度特征融合使提取的特征图信息更加丰富,引用损失函数使得边框回归更加合适与准确。改进的YOLOv5s算法在TrashCan数据集上的mAP由原来的87.3%提高到92.1%,具有较高的精度。

基于聚焦滤波的林业专题地图制图综合方法

森林资源规划设计调查成果总是以连续的面状图斑呈现。当大比例尺二类调查成果图缩编为更小比例尺地图时,常常需要制图综合。如何在制图综合时既要简化多边形边界,又要保持各类型林相面积和位置的相对不变,是林业专题制图的一个难题。经大量实验发现,将实施制图综合的连续面状图斑要素从矢量格式转换为栅格格式,经Focal滤波器以Majority方式滤波处理后,再将滤波后结果从栅格数据转换为矢量数据,可较好地实现森林资源专题连续面状要素信息的制图综合。以云南省某地一个1万hm^(2)的实验区为例,使用该方法将1∶2.5万的森林资源二类调查成果图缩编为1∶25万。结果表明,缩编后,多边形边界简化,目视效果较好,各类型林相面积变化绝对值平均为0.2%,位置精确度平均值为94.68%。此方法已应用于云南森林资源状况图集相关专题图等的生产实践。

锦屏一级水电站库区中小地震震源机制解与局部应力场特征

利用四川及邻区数字地震台网2013—2018年的波形资料,基于CAP和HASH方法反演得到锦屏一级水电站(以下简称锦屏水库)库区及周边M_(L)≥2.5地震的震源机制解,根据DRSSI方法计算得到库区局部应力场信息,结合该区域的地质资料,从震源机制参数和局部应力场变化等方面讨论了水库加卸载对该区域地震活动的影响.取得的主要认识如下:(1)库区地震活动类型以走滑型为主,不同加卸载阶段震源机制类型存在一定差异,库区蓄水前期震源机制类型呈现多样性,蓄水后期与区域背景场趋于一致;(2)库区应力场最大主应力方向以NNW-SSE向为主,分时段结果显示,蓄水后期局部应力场最大主应力方向由NNW向逐渐发生偏转至NW向;(3)库区周边的地质构造和岩性条件有利于库水的渗透,蓄水后重力载荷和流体渗透的共同作用导致岩体断层面库仑应力的变化,从而呈现出库区蓄水前后中小地震活跃程度的显著差异特征.