Seismic random noise suppression using an adaptive nonlocal means algorithm

Nonlocal means filtering is a noise attenuation method based on redundancies in image information. It is also a nonlocal denoising method that uses the self-similarity of an image, assuming that the valid structures of the image have a certain degree of repeatability that the random noise lacks. In this paper, we use nonlocal means filtering in seismic random noise suppression. To overcome the problems caused by expensive computational costs and improper filter parameters, this paper proposes a block-wise implementation of the nonlocal means method with adaptive filter parameter estimation. Tests with synthetic data and real 2D post-stack seismic data demonstrate that the proposed algorithm better preserves valid seismic information and has a higher accuracy when compared with traditional seismic denoising methods （e.g., f-x deconvolution）, which is important for subsequent seismic processing and interpretation.

515队实现持续稳定发展

515队隶属冶金第一地勘局管理:自改革开放以来,特别是近10年来,坚持企业化经营,推进产业结构调整,积极拓展市场,加强领导班子建设,有力地促进地勘经济持续稳定发展。

Field Geological Exploration of the Ashikule Volcano Group in Western Kunlun Mountains

From May 4 to May 30, 2011, a field exploration of the Ashikule basin in the Western Kunlun Mountains area was conducted by a research team from the Institute of Geology, China Earthquake Administration and Earthquake Administration of Xinjiang Uygur Autonomous Region. This work is financially supported by the special fund for China earthquake research project "The Comprehensive Scientific Exploration of the MS7.3 Yutian Earthquake in 2008 and the Ashikule Volcano Group". Through detailed field survey on geological and geomorphological features of the Ashikule volcano group, which is one of the highest altitude volcanic plateaus (about 5000m) in the world, we have determined the total number of volcanoes, the eruption type and structural parameters, and approximate active history of the volcano group. Our studies have provided field evidence for resolving past controversies such as the authenticity of the news report about the eruption event on May 27, 1951, the eruption pattern of the Daheishan volcano, and the reality of the Gaotaishan volcano.

The Spatial Differences and Influencing Factors of Tourism Resources in Ningxia,China

The analysis of the spatial distribution of tourism resources and the identification of its influencing factors are crucial for supporting the sustainable development of regional tourism.This study established a comprehensive database of tourism resources in Ningxia Hui Autonomous Region(Ningxia)through a combination of literature review and field research.It examined the quantitative,qualitative,and categorical characteristics of tourism resources in Ningxia,and determined the spatial patterns based on kernel density and spatial association analysis.This study also comprehensively evaluated the societal,economic,and environmental factors influencing the spatial distribution of tourism resources in the entire region by employing the geographical detector model to quantify the influence of each factor.The following results were obtained.(1)There were 29218 individual tourism resources in Ningxia,comprising eight main types,23 subtypes,and 105 fundamental types,and they exhibit a hierarchical pyramidal structure.(2)The tourism resources in Ningxia displayed characteristics of“widespread regional dispersion and limited regional agglomeration”.The spatial distribution of tourism resources was highly imbalanced,and most types of tourism resources exhibit strong positive spatial correlation.(3)The altitude,annual precipitation,population density,distance from urban centers,urbanization rate,and per capita GDP were identified as significant factors influencing the spatial distribution of tourism resources in Ningxia.Based on the results,we recommend that the government should formulate tourism development policies in Ningxia based on local conditions to effectively address the spatial imbalances,enhance the sustainability of tourism development,and continue to promote high-quality tourism development in Ningxia.

Comparative Analysis of the Spatial-temporal Distribution and Influencing Factors of the Tourism Industry in Three Cities along Beijing-Hangzhou Grand Canal in China

The temporal-spatial pattern of linear cultural heritage in the context of the tourism industry is closely linked to heritage management.Using the 1800 km long Beijing-Hangzhou Grand Canal as an example,this study compared the dynamic evolution of tourism businesses in Beijing,Liaocheng,and Yangzhou at three time points(2010,2015,and 2019)via nearest neighbor analysis,kernel density estimation,and the standard deviational ellipse.Next,a Geo-detector was used to examine the influencing factors.The results reveal significant growth regardless of the quantity or agglomeration degree from 2010 to 2019,and the direction of industrial expansion is consistent with the flow direction of the canal.Moreover,the explanatory powers of factors related to socioeconomic development and canal resources are obviously stronger than those of the natural environment.The findings of this study offer theoretical constructs and policy recommendations for the sustainable development of the Beijing-Hangzhou Grand Canal and other linear cultural heritage sites.

Determination of regional earthquake source parameters in wavelet domain

Investigating source parameters of small and moderate earthquakes plays an important role in seismology research. For small and moderate earthquakes, the mechanisms are usually obtained by first motion of P-Wave, surface wave spectra method in frequency-domain or the waveform inversion in time-domain, based on the regional waveform records. We applied the wavelet domain inversion method to determine mechanism of regional earthquake. Using the wavelet coefficients of different scales can give more information to constrain the inversion. We determined the mechanisms of three earthquakes occurred in California, the United States. They are consistent with the previous results (Harvard Centroid Moment Tensor and United States Geological Service). This proves that the wavelet domain inversion method is an efficient method to determine the source parameters of small and moderate earthquakes, especially the strong aftershocks after a large, disastrous earthquake.