Detecting remotely triggered temporal changes around the Parkfield section of the San Andreas fault

Detecting temporal changes in fault zone properties at seismogenic depth have been a long-sought goal in the seismological community for many decades. Recent studies based on waveform analysis of repeating earthquakes have found clear temporal changes in the shallow crust and around active fault zones associated with the occurrences of large nearby and teleseismic earthquakes. However, repeating earthquakes only occur in certain locations and their occurrence times cannot be controlled, which may result in inadequate sampling of the interested regions or time periods. Recent developments in passive imaging via auto- and cross-correlation of ambient seismic wavefields （e.g., seismic noise, earthquake coda waves） provide an ideal source for continuous monitoring of temporal changes around active fault zones. Here we conduct a systematic search of temporal changes along the Parkfield section of the San Andreas fault by cross-correlating relatively high-frequency （0.4-1.3 Hz） ambient noise signals recorded by 10 borehole stations in the High Resolution Seismic Network. After using stretch/compressed method to measure the delay time and the decorrelation-index between the daily noise cross-correlation functions （NCCFs）, we find clear temporal changes in the median seismic velocity and decorrelation-index associated with the 2004 M6.0 Parkfield earthquake. We also apply the same procedure to the seismic data around five regional/teleseismic events that have triggered non-volcanic tremor in the same region, but failed to find any clear temporal changes in the daily NCCFs. The fact that our current technique can detect temporal changes from the nearby but not regional and teleseismic events, suggests that temporal changes associated with distance sources are very subtle or localized so that they could not be detected within the resolution of the current technique （-0.2%）.

Analysis on Spatial and Temporal Changes of Extreme Precipitation Events in Ningxia in Recent 50 Years

[ Objective] The aim was to study the spatial and temporal changes of extreme precipitation events in Ningxia in recent 50 years. [ Method] Using dally precipitation data at 20 stations in Ningxia from 1961 to 2010, and defining the threshold value of extreme precipitation in each sta- tion by percentage method, choosing indicators such as precipitation, frequency and intensity of extreme precipitation events, the characteristics of the spatial and temporal distribution and linear trend of extreme precipitation events in Ningxia were analyzed based on linear regression and M-K non-parameter statistical test method. [ Result] The percentage method suggested the threshold value of average extreme precipitation in Ningxia in recent 50 years decreased from south to north. The large threshold value was in southern Haiyuan, Tongxin and northern Yancheng, which was similar to the distribution of mean annual precipitation in Ningxia. In recent 50 years, extreme precipitation frequency and extreme precipitation de- creased in most part of Ningxia but the intensity tended to strengthen. Study of extreme precipitation in Mahuang Mountain and Liupan Mountain in- dicated that precipitation frequency, intensity and extreme precipitation reduced. Annual extreme precipitation frequency narrowed and then in- creased after 1994 and had mutation in 2003. Annual extreme precipitation intensity enhanced since 1984. Mutation took place in 1984. Intensity in Liupan Mountain had weakened since 1978. [ Conclusion] The study provided theoretical basis for the mutation of climate in Ningxia.

Analysis of temporal changes in land cover and landscape metrics of a managed forest in the west Black Sea region of northern Turkey: 1970–2010

Forest structure changes continuously by natural and anthropogenic effects. Because the level of goods and services provided by forest ecosystems are related to this structure, some attributes have to be controlled while they are being managed. In this paper we describe the long-term temporal changes in land area and landscape metrics related to different land uses of a managed forest in Turkey. The study was carried out for the Daday Forest Planning Unit located in the west Black Sea region of northern Turkey. The total area is 16,813 ha and besides wood production, it is managed for erosion control, public health, aesthetics, and recreation. Stand type maps that were constructed in 1970,1989, 1999, and 2010 were used in this analysis. Transition matrixes that illustrate area changes among cover types and temporal changes on some landscape metrics were obtained using Geographic Information Systems. Stands were separated into small patches, and thus the number of patches increased nearly two-fold between 1970 and 2010. The total forest edge increased and through the associated fragmentation, the amount of core forest area decreased at the landscape scale. Landscape metrics were applied to digitized versions of historical maps to assess how forest area changed. Human use of the land has changed, forest management practices have evolved, and these along with natural forest growth have contributed to interesting changes in landscape character.

Analysis of Temporal Changes in Botanical Composition of a Long-term Grazing Experiment in Nixinasuno, Japan

In order to understand the temporal changes of botanical composition in grassland ecosystem, and to clarify the relation between these changes and environmental impacts, such as climatic factors and artificial disturbance, a grazing trail was carried out during a 21-year period from 1974 at a sown grassland of the National Grassland Research Institute, located in Nishinasuno, the central area of Japan. The data sets of biomass for each mouth(from April to November)of the 21 year period were analyzed in this paper. The botanical composition of aboveground biomass varied greatly with both season and year. The biomass ratio of improved herbage species to invaded native plants gradually decreased each year. This may have been owing to meteorological factors, such as low air-temperature in winter, dry and hot summers, grassland management(including grazing intensity and fertilizer application), and inter-specific competition between native and introduced herbage plants.

Temporal and spatial changes of suspended sediment concentration and resuspension in the Yangtze River estuary

A detailed analysis of suspended sediment concentration (SSC) variations over a year period is presented using the data from 8 stations in the Yangtze River estuary and its adjacent waters, together with a discussion of the hydrodynamic regimes of the estuary. Spatially, the SSC from Xuliujing downwards to Hangzhou Bay increases almost constantly, and the suspended sediment in the inner estuary shows higher concentration in summer than in winter, while in the outer estuary it shows higher concentration in winter than in summer, and the magnitude is greater in the outer estuary than in the inner estuary, greater in the Hangzhou Bay than in the Yangtze River estuary. The sediments discharged by the Yangtze River into the sea are resuspended by marine dynamics included tidal currents and wind waves. Temporally, the SSC shows a pronounced neap-spring tidal cycle and seasonal variations. Furthermore, through the analysis of dynamic mechanism, it is concluded that wave and tidal current are two predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles, and wind waves control seasonal variations. The ratio between river discharge and marine dynamics controls spatial distribution of SSC.

Temporal changes in the characteristics of algae in Dianchi Lake,Yunnan Province,China

Algal blooms have become a worldwide environmental concern due to water eutrophication.Dianchi Lake in Yunnan Province,China is suffering from severe eutrophication and is listed in the Three Important Lakes Restoration Act of China.Hydrothermal liquefaction allows a promising and direct conversion of algal biomass into biocrude oil.In this study,algal samples were collected from Dianchi Lake after a separation procedure including dissolved air flotation with polyaluminum chloride and centrifugation during four months,April,June,August and October.The algal biochemical components varied over the period;lipids from 0.7%to 2.1%ash-free dry weight(afdw),protein from 20.9%to 33.4%afdw and ash from 36.6%to 45.2%dry weight.The algae in June had the highest lipid and protein concentrations,leading to a maximum biocrude oil yield of 24.3%afdw.Biodiversity analysis using pyrosequencing revealed different distributions of microbial communities,specifically Microcystis in April(89.0%),June(63.7%)and August(84.0%),and Synechococcus in April(2.2%),June(12.0%)and August(1.0%).This study demonstrated remarkable temporal changes in the biochemical composition and biodiversity of algae harvested from Dianchi Lake and changes in biocrude oil production potential.

Analysis of Temporal and Spatial Changes of Cultivated Land in Karst Areas of Southwest Guangxi Based on Landscape Pattern Indices

Affected by topographical conditions,the distribution of cultivated land in karst areas is relatively fragmented.More effective cultivated land protection measures can be taken in a targeted manner by grasping the spatial and temporal distribution characteristics of regional cultivated land.In this study,with the cultivated land of four county-level administrative regions(Debao County,Jingxi City,Daxin County,and Tiancheng County)in typical karst landform areas in southwestern Guangxi as the research object,combining with the spatial analysis function of the GIS software platform,the spatial distribution characteristics and temporal and spatial changes of cultivated land in the study area were investigated from 2009 to 2020 using the quantitative analysis method of landscape pattern indices,revealing the main problems of cultivated land utilization,and the multi-dimensional management ideas of cultivated land protection in karst areas under the background of rural revitalization strategy were proposed.

Temporal and spatial variation of cloud cover in arid regions of Central Asia in the last 40 years

Water resources are one of the key factors restricting the development of arid areas,and cloud water resources is an important part of water resources.The arid region of central Asia is the core region of the current national green silk road construction,and is the largest arid region in the world.Based on cloud cover data of ECMWF,the current study analyzed temporal and spatial characteristics of cloud properties in arid regions of Central Asia between 1980 and 2019.Our findings show that:(1)From the point of view of spatial distribution,total cloudiness in arid regions of Central Asia was low in the south and high in the north.The distribution of high cloud frequency and medium cloud frequency was higher in the south and lower in the north,while low cloud frequency distribution was low in the south and high in the north.(2)In terms of time,the variation of cloud cover and cloud type frequency had obvious seasonal characteristics.From winter to spring,cloud cover increased,and the change of cloud type frequency increased.From spring to summer,cloud cover continued to increase and the change of cloud type frequency increased further.Cloud cover began to decrease from summer to autumn,and the change of cloud type frequency also decreased.(3)Generally,average total cloud cover decreased in most of central Asia,and high and medium cloud cover increased while low cloud cover decreased.This study provides a reference for the rational development of cloud resources in the region.

Empirical Changes in the Prevalence of Overweight and Obesity among Chinese Students from 1985 to 2010 and Corresponding Preventive Strategies

Objective To determine the extent of the obesity epidemic in school‐aged Chinese children in 2010 and track the increasing trend in different socioeconomic regions over the preceding 25 years. Strategies for preventing childhood obesity are suggested. Methods We used a dataset provided by the Chinese National Survey on Students’ Constitution and Health from 1985‐2010. Subjects were 7‐18‐year‐old students randomly selected from urban and rural areas in 30 provinces. Eight subgroups were created according to region and socioeconomic status. Results Increased rates of the epidemic （overweight and obesity combined） were greatest in large coastal cities‐32.6% and 19.1% among males and females, respectively. These rates has neared that of developed countries. Similar increases were found in all other regions, including the once poverty‐stricken rural west. The epidemic in most of the rural areas began after 2000, but has spread swiftly over the last decade. In 2010, it was estimated that 9.9% of Chinese school‐aged children and adolescents were overweight and that an additional 5.1% were obese, representing an estimated 30.43 million individuals. Conclusion The prognosis for China＇s childhood‐obesity epidemic is dire. To prevent childhood obesity, we suggest several strategies, including reasonable dietary intake, increase physical activity, a change in sedentary lifestyles and corresponding behavioral modifications.

Surface air temperature change in the Wuyi Mountains,southeast China

Detecting changes in surface air temperature in mid-and low-altitude mountainous regions is essential for a comprehensive understanding of warming trend with altitude.We use daily surface air temperature data from 64 meteorological stations in Wuyi Mountains and its adjacent regions to analyze the spatio-temporal patterns of temperature change.The results show that Wuyi Mountains have experienced significant warming from 1961 to 2018.The warming trend of the mean temperature is 0.20℃/decade,the maximum temperature is 0.17℃/decade,and the minimum temperature is 0.26℃/decade.In 1961-1990,more than 63%of the stations showed a decreasing trend in annual mean temperature,mainly because the maximum temperature decreased during this period.However,in 1971-2000,1981-2010 and 1991-2018,the maximum,minimum and mean temperatures increased.The fastest increasing trend of mean temperature occurred in the southeastern coastal plains,the quickest increasing trend of maximum temperature occurred in the northwestern mountainous region,and the increase of minimum temperature occurred faster in the southeastern coastal and northwestern mountainous regions than that in the central area.Meanwhile,this study suggests that elevation does not affect warming in the Wuyi Mountains.These results are beneficial for understanding climate change in humid subtropical middle and low mountains.

Vegetation changes in the agricultural-pastoral areas of northern China from 2001 to 2013

Climate change and human activity have resulted in increasing change of vegetation growth globally. Numerous studies have been conducted on extreme climate events and analyses of ecological environment evolution. However, such studies have placed little emphasis on vegetation change and spatial variation in this type of ecotone. Accordingly, this study analyzed the changes in vegetation type and growth using the 16-d composite MOD13A1 product with 1-km resolution and MOD12Q1 product with 1-km resolution. We used the mean, maximum, standard deviation normalized-difference vegetation index（NDVI） values, and the rate of change（ROC） of NDVI value to explain vegetation changes within the studied ecotone. Our results showed that significant vegetation type and growth changes have occurred in the study area. From 2001 to 2013, for example, with the exception of 2001, 2004 and 2009, a certain extent of grassland area was converted to cropland. Drought severity index（DSI） results indicate that there exists drought in 2001, 2004 and 2009. Such temporal changes in cropland and grassland area confirmed the ecological vulnerability of the ecotone. At the same time, vegetation varied spatially from west to east and from south to north. The mean, maximum and standard deviation NDVI values were all sorted in descending order based on differences in latitude and longitude, as follows： NDVI_（2013）〉NDVI_（2009）〉NDVI_（2004）〉NDVI_（2001）

Localized temporal variation of Earth's inner-core boundary from high-quality waveform doublets

The topography of the inner core is crucial to understand its growth process and interaction with the geodynamo. With the accuracy of teleseismic waveform doublets in determining the travel-time shifts between PKPcd and PKPdf inner-core phases, we examined the temporal change of the inner-core boundary sampled by new earthquake doublets that occurred in the Western Pacific and those previously found from the South Sandwich Islands. The receiver stations are those within the distance range of 128°–142° from the hypocenters of the waveform doublets. Our results suggest that temporal changes in PKPcd-PKPdf differential times are very subtle except some isolated regions under central America and Africa. The observations may indicate localized topography of the inner core and/or the inner-core boundary as transient slurry in isolated regions.

Magnetic Particle Imaging for Magnetic Hyperthermia Treatment: Visualization and Quantification of the Intratumoral Distribution and Temporal Change of Magnetic Nanoparticles in Vivo

Purpose: Magnetic hyperthermia treatment (MHT) is a strategy for cancer therapy using the tem-perature rise of magnetic nanoparticles (MNPs) under an alternating magnetic field (AMF). Re-cently, a new imaging method called magnetic particle imaging (MPI) has been introduced. MPI allows imaging of the spatial distribution of MNPs. The purpose of this study was to investigate the feasibility of visualizing and quantifying the intratumoral distribution and temporal change of MNPs and predicting the therapeutic effect of MHT using MPI. Materials and Methods: Colon-26 cells (1 × 106 cells) were implanted into the backs of eight-week-old male BALB/c mice. When the tumor volume reached approximately 100 mm3, mice were divided into untreated (n = 10) and treated groups (n = 27). The tumors in the treated group were directly injected with MNPs (Resovist?) with iron concentrations of 500 mM (A, n = 9), 400 mM (B, n = 8), and 250 mM (C, n = 10), respectively, and MHT was performed using an AMF with a frequency of 600 kHz and a peak amplitude of 3.5 kA/m. The mice in the treated group were scanned using our MPI scanner immediately before, immediately after, 7 days, and 14 days after MHT. We drew a region of interest (ROI) on the tumor in the MPI image and calculated the average, maximum, and total MPI values and the number of pixels by taking the threshold value for extracting the contour as 40% of the maximum MPI value (pixel value) within the ROI. These parameters in the untreated group were taken as zero. We also measured the relative tumor volume growth (RTVG) defined by (V-V0)/V0, where V0 and V are the tumor volumes immediately before and after MHT, respectively. Results: The average, maximum, and total MPI values decreased up to 7 days after MHT and remained almost constant thereafter in all groups, whereas the number of pixels tended to increase with time. The RTVG values in Groups A and B were significantly lower than those in the control group 3 days or more and 5 days or more after MHT, respectively. The above four parameters were significantly inversely correlated with the RTVG values 5, 7, and 14 days after MHT. Conclusion: MPI can visualize and quantify the intratumoral distribution and temporal change of MNPs before and after MHT. Our results suggest that MPI will be useful for predicting the therapeutic effect of MHT and for the treatment planning of MHT.

Vegetation Coverage Changes in the West Qinling Region from 2000 to 2010:A Case Study of Longnan City

As the main content of terrestrial ecosystem study,vegetation coverage change has gained extensive attention in the process of global climate change and sustainable development recently.Based on MODIS NDVI data from June to October during 2000-2010,taking Longnan City as a case area,this paper develops the calculation method of vegetation coverage(VC) by using Pixel Dichotomy model and analyzes the spatial-temporal variation of vegetation coverage in the West Qinling region by using simple linear regression and standard deviation method.The results show that vegetation coverage remains stable and is significantly correlated with temperature and precipitation during the decade.The vegetation coverage of 90% of study area shows stability with small annual variation and also is consistent with the spatial distribution of forest land;the vegetation coverage in the remaining study areas shows a growing trend with significant variation and also is consistent with the spatial distribution of farmland and grassland,especially in Huicheng Basin,Xili Basin and adret slope of Bailongjiang River Valley,indicating that Project about the Conversion of Degraded Farmland into Forest has made a great contribution to vegetation coverage increase.This paper proves the effect of ecology construction in the West Qinling region since the late 20 th century.All the findings also provide references for local ecological environment construction and sustainable development.

Community structure and spatial-temporal variation of netzphytoplankton in the Bering Sea in summer

Marine biodiversity is changing in response to altered physical environment, subsequent ecological changes as well as anthropogenic disturbances. In this study, phytoplankton samples in situ collected in the Bering Sea in July of 1999 and 2010 were analyzed to obtain phytoplankton community structure and spatial-temporal variation between the beginning and end of this decade, and the correlation of phytoplankton community dynamics and environmental factors was investigated. A total of 5 divisions, 58 genera and 153 species of phytoplankton belonging to 3 ecological groups were identified. The vast majority of phytoplankton consisted of diatoms accounting for 66.7% of the total species and 95.2% of the total abundance. Considering differentiation in spatial extent and phytoplankton sample types, there were subtle changes in species composition, large altering in abundance and significant variation in spatial distribution between two surveys. The abundance peak area was located at the Bering Strait while sub peak was found at the Bering Sea Basin. The boreal-temperate diatom was the dominant flora, which was subsequently replaced by eurythermal and frigid-water diatom. Phytoplankton community in the Bering Sea was not a simplex uniform community but composed of deep-ocean assemblage and neritic assemblage. The deep-ocean assemblage was located in the northwestern Pacific Ocean and Bering Sea Basin, dominated by boreal-temperate species（Neodenticula seminae, Thalassiothrix longissima, Amphiprora hyperborean, Chaetoceros atlanticus, Thalassiosira trifulta, etc.） and eurychoric species（Thalassionema nitzschioides, Ch. compressus, Rhizosolenia styliformis, etc.）, and characterized by low abundance, even interspecies abundance allocations, diverse dominant species and high species diversity. The neritic assemblage was distributed on the continental shelf and slope of Bering Sea and was mainly composed of frigid-water species（Th.nordenski？ldii, Ch. furcellatus, Ch. socialis, Bacteriosira fragilis, etc.） and eurythermal and euryhaline species（L.danicus, Ch. curvisetus, Coscinodiscus curvatulus, etc.）, and it was characterized by high abundance, uneven interspecies allocations, prominent dominant species and low species diversity. Spatial-temporal variation of species composition and abundance of phytoplankton in the Bering Sea was directly controlled by surface circulation,nutrient supply and ice edge.

Tear inflammation related indexes after cataract surgery in elderly patients with type 2 diabetes mellitus

BACKGROUND Quantitative studies on the changes in inflammation-related content in tears,especially the effect of diabetes,are lacking.In this study,we measured the preoperative and postoperative tear inflammatory mediator levels in cataract patients,focusing on the expression of inflammatory factors in postoperative cataracts in the diabetic,and investigated the effect of drugs on the control of postoperative inflammation.AIM To study the expression of inflammatory factors in elderly people with type 2 diabetes after cataract surgery.METHODS Patients with a mean age of 70.3±6.3 years were divided into group A(composed of elderly patients with cataracts and type 2 diabetes,n=20 eyes)and group B(patients with age-related cataract,n=20 eyes).Their tears were collected before each operation and on days 1 and 3,and weeks 1,2,3,and 4 post-surgery.Saline(150μL)was dropped into the conjunctival sac of the surgical eye,followed by oculogyration in four directions.The fluid in the conjunctival sac was extracted using a sterile syringe and stored in Eppendorf tubes at-80°C until measurement.The expression levels of matrix metalloproteinase-2(MMP-2),MMP-9,tissue inhibitor of metalloproteinase-1(TIMP-1),TIMP-2,interleukin-6(IL-6),and IL-20 in tear fluid were measured using enzyme-linked immunosorbent assays.RESULTS The postoperative expression levels of MMP-2,MMP-9,TIMP-2,IL-6,and IL-20 in group A were significantly higher than those in group B,whereas the concentration of TIMP-1 in group A remained lower than that in group B.The levels of MMP-2 and IL-6 in both groups continuously increased until the peak in the first postoperative week,and then gradually decreased over the next three weeks.Ultimately,MMP-2 declined to a lower level than that preoperatively at week 4,but IL-6 decreased to the same level as that preoperatively.The level of MMP-9 peaked in the first two weeks postoperative and then returned to the same level as 1-day post-operation.The concentration of TIMP-1 post-operation remained constant at a lower level than before surgery,and TIMP-2 Levels remained stable in both groups.IL-20 content started to increase in the third week after surgery.CONCLUSION Inflammatory factor levels in tears fluctuated before and post-operation,which indicated more severe postoperative inflammation in the first two weeks.

Recent advances in imaging crustal fault zones: a review

Crustal faults usually have a fault core and surrounding regions of brittle damage, forming a low-velocity zone （LVZ） in the immediate vicinity of the main slip interface. The LVZ may amplify ground motion, influence rupture propagation, and hold important information of earthquake physics. A number of geophysical and geodetic methods have been developed to derive high-resolution structure of the LVZ. Here, I review a few recent approaches, including ambient noise cross-correlation on dense across-fault arrays and GPS recordings of fault-zone trapped waves. Despite the past efforts, many questions concerning the LVZ structure remain unclear, such as the depth extent of the LVZ. High-quality data from larger and denser arrays and new seismic imaging technique using larger portion of recorded waveforms, which are currently under active development, may be able to better resolve the LVZ structure. In addition, effects of the alongstrike segmentation and gradational velocity changes across the boundaries between the LVZ and the host rock on rupture propagation should be investigated by conducting comprehensive numerical experiments. Furthermore, high-quality active sources such as recently developed large-volume airgun arrays provide a powerful tool to continuously monitor temporal changes of fault-zone properties, and thus can advance our understanding of fault zone evolution.

Biological responses of small yellow croaker(Larimichthys polyactis) to multiple stressors: a case study in the Yellow Sea, China

Temporal changes in biological characteristics of small yellow croaker Larimichthys polyactis in the Yellow Sea were examined for the period of 1960–2008. The body size and age of small yellow croaker decreased substantially, in particular, average length of fish in 2008 was reduced by ~85% than those occurring in 1985, and at that time ~93% of the total catch was dominated by one-year-old individuals. Correspondingly, growth parameters also varied significantly over the years, i.e., k（growth coefficient） and t_0（zero-length age） gradually increased from 0.26 and –0.58 year in 1960 to 0.56 and –0.25 year in 2008, respectively. Although, L∞（body length）sharply decreased from 34.21 cm in 1960 to 24.06 cm in 2008, and t_r（inflexion age） decreased from 3.78 year in1960 to 1.61 year in 2008. There was a great increase both in natural mortality coefficient and fishing mortality coefficient. However, according to the gray correlation analysis, changes in the biological characteristics of small yellow croaker were induced by different stressors ranked as： fishing vessel power〉feeding grade〉sea surface temperature. This study suggests that the active fishery management measures for biological characters of fish populations should be considered.

Illuminating high-resolution crustal fault zones using multi-scale dense arrays and airgun source

High-resolution imaging of fault zone structure and its temporal changes can not only advance our understanding of earthquake physics,but is also critical for better seismic hazard preparation and mitigation.In the past a few years,we deployed multi-scale dense arrays across the Chenghai fault system in Binchuan,Yunnan,China.The first array consisted of 381 intermediate-period three-component seismometers with an average station spacing of~2 km.The array has been deployed in the field for~3 months in 2017 and recorded numerous local and teleseismic earthquakes.Travel time analyses based on teleseismic earthquakes and an airgun source in the region indicated clear signature of low-velocity fault zones in the southern branch of the Chenghai fault system.In 2018 we deployed two other linear arrays using the same instruments with much smaller inter-station spacing,e.g.30-50 m,across the southern branch the Chenghai fault.The profile lengths were 8 and 5 km,respectively.Record sections of the airgun source on the two linear arrays clearly marked a low-velocity zone(LVZ)within the southern array but no such signature in the northern array,suggesting along-strike variation of the LVZ.Although the instruments within our dense arrays had an intermediate frequency band,we demonstrated that they were capable of characterizing crustal structure with techniques commonly applied to broadband signals such as receiver functions.To our best knowledge,this was the first time to have multi-scale across-fault dense arrays with three-component seismometers in such apertures.These results lay out the pavement to comprehensively investigate fault zone structures as well as to derive subsurface structural changes using dense arrays and the airgun source.