scholarly journals Spatio-temporal distribution of shallow very-low-frequency earthquakes between December 2020 and January 2021 in Kumano-nada, Nankai subduction zone, detected by a permanent seafloor seismic network

2022 ◽  
Vol 74 (1) ◽  
Author(s):  
Yojiro Yamamoto ◽  
Keisuke Ariyoshi ◽  
Shuichiro Yada ◽  
Masaru Nakano ◽  
Takane Hori
Keyword(s):  
Fluid Pressure ◽  
Low Frequency ◽  
Temporal Distribution ◽  
Active Area ◽  
Small Scale ◽  
Very Low Frequency ◽  
Eastern Side ◽  
Activity Area ◽  
Spatio Temporal ◽  
Western Side

AbstractWe estimate the hypocenter locations and the centroid moment tensor solutions of the shallow very-low-frequency earthquake (sVLFE) activity that occurred in the Kumano-nada region of the Nankai Trough megathrust zone in central Japan from December 2020 to January 2021. Using seafloor observation data, we examined the detailed spatio-temporal distribution of the sVLFE activity. During this episode, the activity area was within the vicinity in which the sVLFE activity has been observed in the past and can be divided into two major parts. The sVLFE activity started from the eastern side and remained there for the first 5 days and then migrated to the western side via secondary expansion. The eastern active area is located just below the outer ridge and coincides with the location where the paleo-Zenith Ridge subducted. The western activity area is centered between the outer wedge and the outer ridge with the primary active area being at the outer wedge. Comparing the activity in the eastern and western areas, the eastern side is more active, but the individual moment releases on this side are smaller than those on the western side. This may indicate a difference in the fluid pressure along the plate boundary between the eastern and western areas. After the second expansion of the active area, we observed several migration patterns within the expanded area with a faster velocity than those of the initial and second expansions. The direction of these migrations is opposite to that of the first and second expansions. This indicates that the fluid pressure and/or stress level in the sVLFE generation region changed with time within this episode. Furthermore, many waveforms with sVLFE characteristics were observed at only one or a few observation points near the trough axis in the middle to latter half of January 2021. This indicates the occurrence of small-scale sVLFEs in the vicinity of the trough axis at the end of this sVLFE episode. Graphical Abstract

scholarly journals Spatio-Temporal Distribution of Shallow Very-Low-Frequency Earthquakes between December 2020 and January 2021 in Kumano-Nada, Nankai Subduction Zone, Detected by A Permanent Seafloor Seismic Network

2021 ◽  
Author(s):  
Yojiro Yamamoto ◽  
Keisuke Ariyoshi ◽  
Shuichiro Yada ◽  
Masaru Nakano ◽  
Takane Hori
Keyword(s):  
Fluid Pressure ◽  
Low Frequency ◽  
Temporal Distribution ◽  
Active Area ◽  
Small Scale ◽  
Very Low Frequency ◽  
Eastern Side ◽  
Activity Area ◽  
Spatio Temporal ◽  
Western Side

Abstract We estimate the hypocenter locations and the centroid moment tensor solutions of the shallow very-low-frequency earthquake (sVLFE) activity that occurred in the Kumano-nada region of the Nankai Trough megathrust zone in central Japan from December 2020 to January 2021. Using seafloor observation data, we examined the detailed spatio-temporal distribution of the sVLFE activity. During this episode, the activity area was within the vicinity in which the sVLFE activity has been observed in the past and can be divided into two major parts. The sVLFE activity started from the eastern side and remained there for the first 5 days and then migrated to the western side via secondary expansion. The eastern active area is located just below the outer ridge and coincides with the location where the paleo-Zenith Ridge is subducted. The western activity area is centered between the outer wedge and the outer ridge with the primary active area being at the outer wedge. Comparing the activity in the eastern and western areas, the eastern side is more active, but the individual moment releases on this side are smaller than those on the western side. This may indicate a difference in the fluid pressure along the plate boundary between the eastern and western areas. After the second expansion of the active area, we observed several migration patterns within the expanded area with a faster velocity than those of the initial and second expansions. The direction of these migrations is opposite to that of the first and second expansions. This indicates that the fluid pressure and/or stress level in the sVLFE generation region changed with time within this episode. Furthermore, many waveforms with sVLFE characteristics were observed at only one or a few observation points near the trough axis in the middle to latter half of January 2021. This indicates the occurrence of small-scale sVLFEs in the vicinity of the trough axis at the end of this sVLFE episode.

scholarly journals Spatial and seasonal patterns of FMD primary outbreaks in cattle in Zimbabwe between 1931 and 2016

2019 ◽  
Vol 50 (1) ◽  
Author(s):  
Laure Guerrini ◽  
Davies Mubika Pfukenyi ◽  
Eric Etter ◽  
Jérémy Bouyer ◽  
Chenjerai Njagu ◽  
...  
Keyword(s):  
Protected Areas ◽  
Southern Africa ◽  
Production Systems ◽  
Temporal Distribution ◽  
Foot And Mouth Disease ◽  
Control Measures ◽  
Political Crisis ◽  
Small Scale ◽  
Temporal Occurrence ◽  
Spatio Temporal

Abstract Foot and mouth disease (FMD) is an important livestock disease impacting mainly intensive production systems. In southern Africa, the FMD virus is maintained in wildlife and its control is therefore complicated. However, FMD control is an important task to allow countries access to lucrative foreign meat market and veterinary services implement drastic control measures on livestock populations living in the periphery of protected areas, negatively impacting local small-scale livestock producers. This study investigated FMD primary outbreak data in Zimbabwe from 1931 to 2016 to describe the spatio-temporal distribution of FMD outbreaks and their potential drivers. The results suggest that: (i) FMD outbreaks were not randomly distributed in space across Zimbabwe but are clustered in the Southeast Lowveld (SEL); (ii) the proximity of protected areas with African buffalos was potentially responsible for primary FMD outbreaks in cattle; (iii) rainfall per se was not associated with FMD outbreaks, but seasons impacted the temporal occurrence of FMD outbreaks across regions; (iv) the frequency of FMD outbreaks increased during periods of major socio-economic and political crisis. The differences between the spatial clusters and other areas in Zimbabwe presenting similar buffalo/cattle interfaces but with fewer FMD outbreaks can be interpreted in light of the recent better understanding of wildlife/livestock interactions in these areas. The types of wildlife/livestock interfaces are hypothesized to be the key drivers of contacts between wildlife and livestock, triggering a risk of FMD inter-species spillover. The management of wildlife/livestock interfaces is therefore crucial for the control of FMD in southern Africa.

scholarly journals Satellite-Derived Spatio-Temporal Distribution and Parameters of North Atlantic Polar Lows for 2015–2017

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 224
Author(s):  
Pavel Golubkin ◽  
Julia Smirnova ◽  
Leonid Bobylev
Keyword(s):  
North Atlantic ◽  
Barents Sea ◽  
Auxiliary Information ◽  
Low Frequency ◽  
Temporal Distribution ◽  
Study Region ◽  
Polar Lows ◽  
Mean Values ◽  
Polar Low ◽  
Spatio Temporal

A list of North Atlantic polar lows was compiled for 2015–2017. A total of 131 polar lows were found by analyzing the Moderate Resolution Imaging Spectroradiometer (MODIS) infrared imagery and auxiliary information. The study region was additionally divided by the 20° W meridian to assess possible differences in the polar lows occurring in the western and eastern parts of the region. The highest polar low activity was found over the Barents Sea and the northern Norwegian Sea. A large number of polar lows over this region were dual or multiple. When considering such systems as a single event, more polar lows were found in 2015 over the Labrador Sea and southern Davis Strait, which is the region with the second highest number of polar lows. High interannual variability of polar low frequency was noted, which was more pronounced in the western part of the region. During the analyzed period, the largest number of polar lows occurred in January for the western part of the region and in February for the eastern part. The main polar low parameters were similar within the region, with the mean values slightly higher in the western part of the region, but all extreme high values were observed in the eastern part.

scholarly journals Spatio-Temporal Characteristics of SO2 across Weifang from 2008 to 2020

2021 ◽  
Vol 18 (22) ◽  
pp. 12206
Author(s):  
Lining Zhu ◽  
Yu Zhang ◽  
Zheng Wu ◽  
Chengcheng Zhang
Keyword(s):  
Wind Direction ◽  
Quantitative Research ◽  
Pollution Prevention ◽  
Temporal Distribution ◽  
Research Area ◽  
Small Scale ◽  
Macro Scale ◽  
Spatio Temporal ◽  
The Impact ◽  
So2 Pollution

China has achieved good results in SO2 pollution control, but SO2 pollution still exists in some areas. Analyzing the spatio-temporal distribution of SO2 is critical for regional SO2 pollution prevention and control. Compared with existing air pollution studies that paid more attention to PM2.5, NO2 and O3, and focused on the macro scale, this study took the small-scale Weifang city as the research area, analyzed the temporal and spatial changes in SO2, discussed the migration trajectory of SO2 pollution and explored the impact of wind on SO2 pollution. The results show that the average annual concentration of SO2 in Weifang has exhibited a downward trend in the past 13 years, showing the basic characteristics of “highest in winter, lowest in summer and slightly higher in spring and autumn”, “highest on Sunday, lowest on Thursday and gradually decreasing from Monday to Thursday” and “highest at 9 a.m., lowest at 4 p.m. and gradually increasing from midnight to 9 a.m.”. SO2 concentration showed obvious spatial heterogeneity: higher in the north and lower in the south. In addition, Shouguang, Changyi and Gaomi were seriously polluted. The SO2 pollution shifted from south to northeast. The clean wind direction (southeast wind and northeast wind) of Weifang city accounted for about 41%, and the pollution wind direction (northwest wind and west wind) accounted for about 7%. Drawing from the multi-scale analysis, vegetation, precipitation, temperature, transport situation and human activity were the most relevant factors. Limited to data collection, more quantitative research is needed to gain insight into the influence mechanism in the future.

scholarly journals Spatio-Temporal Distribution of Carabids Influenced by Small-Scale Admixture of Oak Trees in Pine Stands

Diversity ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 398
Author(s):  
Alexandra Wehnert ◽  
Sven Wagner ◽  
Franka Huth
Keyword(s):  
Linear Models ◽  
Interspecific Interactions ◽  
Temporal Distribution ◽  
Quercus Petraea ◽  
Small Scale ◽  
Spatial Effects ◽  
Oak Trees ◽  
Geostatistical Models ◽  
Temporal And Spatial ◽  
Spatio Temporal

In a region with poor soil fertility, low annual precipitation and large areas of homogenous Pinus sylvestris L. forests, conservation of old sessile oak (Quercus petraea (Matt.) Liebl.) trees is one option to enrich structure and species richness. We studied the affinities of Carabus coriaceus, C. violaceus, C. hortensis and C. arvensis for specific tree species and the resultant intra- and interspecific interactions. We focused on their temporal and spatial distributions. Pitfall traps were used as a surface-related capture method on a grid over an area of three hectares. Generalised linear models and generalised linear geostatistical models were used to analyse carabid activity densities related to distance-dependent spatial effects corresponding to tree zones (oak, oak–pine, pine). The results demonstrated significant spatial affinities among these carabids, especially for females and during the period of highest activity. Individuals of C. coriaceus showed a tendency to the oak zone and C. hortensis exhibited a significant affinity to the oak–pine mixture. Imagines of C. arvensis and C. violaceus were more closely related to pine. The observed temporal and spatial coexistence of the different Carabus species reveals that single admixed old oak trees can support greater diversity within pine-dominated forests.

Spontaneous generation of a swirling plume in a stratified ambient

2014 ◽  
Vol 761 ◽  
pp. 443-463 ◽  
Author(s):  
Francisco Marques ◽  
Juan M. Lopez
Keyword(s):  
Temporal Dynamics ◽  
Numerical Study ◽  
Three Dimensional ◽  
Low Frequency ◽  
Spontaneous Generation ◽  
Fixed Temperature ◽  
Very Low Frequency ◽  
External Perturbations ◽  
Spatio Temporal ◽  
Set Up

AbstractThe transition from laminar to complex spatio-temporal dynamics of plumes due to a localized buoyancy source is studied numerically. Several experiments have reported that this transition is sensitive to external perturbations. Therefore, a well-controlled set-up has been chosen for our numerical study, consisting of a localized heat source at the bottom of an enclosed cylinder whose sidewall is maintained at a fixed temperature which varies linearly up the wall. Restricting the dynamics to the axisymmetric subspace, the first instability is to a puffing state. However, for smaller Grashof numbers, the plume becomes unstable to three-dimensional perturbations and a swirling plume spontaneously appears. The next bifurcation, viewed in the rotating frame where the plume is stationary, also exhibits puffing and suggests a connection between the unstable axisymmetric puffing solution and the swirling plume. Further bifurcations result in quasi-periodic states with a very low-frequency modulation, and these eventually become spatio-temporally complex.

scholarly journals Spatio-Temporal Distribution of Aedes Albopictus and Culex Pipiens along an Urban-Natural Gradient in the Ventotene Island, Italy

2020 ◽  
Vol 17 (22) ◽  
pp. 8300
Author(s):  
Mattia Manica ◽  
Sara Riello ◽  
Carolina Scagnolari ◽  
Beniamino Caputo
Keyword(s):  
Aedes Albopictus ◽  
Culex Pipiens ◽  
Urban Landscape ◽  
Migratory Birds ◽  
Temporal Distribution ◽  
Pathogen Transmission ◽  
Current Evidence ◽  
Small Scale ◽  
Stopover Site ◽  
Spatio Temporal

The distribution of mosquitos and their corresponding hosts is critical in public health to determine the risk of transmission for vector-borne diseases. In this pilot study conducted in the small Mediterranean island of Ventotene, a known stopover site for migratory birds, the spatio-temporal distribution of two major mosquito vectors is analyzed from the natural to urban environment. The results show that Aedes albopictus aggregates mostly near areas with a human presence and the urban landscape, while Culex pipiens is more spatio-temporally spread, as it can also be found in wilder and less anthropized areas where the availability of human hosts is limited. Culex pipiens is also active earlier in the year. From a microgeographical perspective, our results confirm the anthropophilic spatial distribution of Ae. Albopictus, while suggesting that the circulation of bird zoonosis, such as West Nile, could be favored by the Cx. pipiens distribution. The results highlight the different ecology of the vectors and the interplay with their hosts, even at a small scale. The current evidence may help in forecasting the risk of pathogen transmission and surveillance planning.

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