Remote Triggering of Icequakes at Mt. Erebus, Antarctica by Large Teleseismic Earthquakes

2021 ◽  
Author(s):  
Chenyu Li ◽  
Zhigang Peng ◽  
Julien A. Chaput ◽  
Jacob I. Walter ◽  
Richard C. Aster
Keyword(s):  
Austral Summer ◽  
High Elevation ◽  
Small Scale ◽  
Volcano Observatory ◽  
Seismic Triggering ◽  
Stress Changes ◽  
Before And After ◽  
The Antarctic ◽  
Erebus Volcano ◽  
Large Earthquakes

Abstract Recent studies have shown that the Antarctic cryosphere is sensitive to external disturbances such as tidal stresses or dynamic stresses from remote large earthquakes. In this study, we systematically examine evidence of remotely triggered microseismicity around Mount (Mt.) Erebus, an active high elevation stratovolcano located on Ross Island, Antarctica. We detect microearthquakes recorded by multiple stations from the Mt. Erebus Volcano Observatory Seismic Network one day before and after 43 large teleseismic earthquakes, and find that seven large earthquakes (including the 2010 Mw 8.8 Maule, Chile, and 2012 Mw 8.6 Indian Ocean events) triggered local seismicity on the volcano, with most triggered events occurring during the passage of the shorter-period Rayleigh waves. In addition, their waveforms and locations for the triggered events are different when comparing with seismic events arising from the persistent small-scale eruptions, but similar to other detected events before and after the mainshocks. Based on the waveform characteristics and their locations, we infer that these triggered events are likely shallow icequakes triggered by dilatational stress perturbations from teleseismic surface waves. We show that teleseismic earthquakes with higher peak dynamic stress changes are more capable of triggering icequakes at Mt. Erebus. We also find that the icequakes in this study are more likely to be triggered during the austral summer months. Our study motivates the continued monitoring of Mount Erebus with dense seismic instrumentation to better understand interactions between dynamic seismic triggering, crospheric processes, and volcanic activity.

Study of Diabetic Mellitus and Knowledge of Lotion Foot Care on the Community

2018 ◽  
Vol 9 (3) ◽  
Author(s):  
Hariyadi DM ◽  
Athiyah U ◽  
Hendradi E ◽  
Rosita N ◽  
Erawati T ◽  
...  
Keyword(s):  
Blood Glucose ◽  
T Test ◽  
Small Scale ◽  
Scale Production ◽  
Foot Care ◽  
Diabetic Mellitus ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Before And After ◽  
History Of

The prevention of Diabetic Mellitus (DM) and its complications is the main aim of this study, in addition to the training of lotion foot care application and the development of small scale industry. The research team delivered knowledge in the form of training on Diabetic Mellitus, healthy food, treatment and prevention of complications, and small-scale production of cosmetic products. The aim of this study was to determine the correlation between training on diabetic and lotion foot care application as preventive measures against diabetic complications on the patient's blood glucose levels in the community of residents in Banyuurip Jaya, Surabaya. It was expected from this training that the knowledge of the residents increases and people living with diabetic undergo lifestyle changes and therefore blood sugar levels can be controlled. The parameters measured in this research were blood glucose levels, the anti diabetic drug types consumed, and compliance on diabetics. This study used the data taken from 60 patients with DM over a period of one month. Questionnaires and log books was used to retrieve data and changes in blood glucose levels in diabetic patients. The results showed the demographic data of patients with type 2 diabetic of 85% female and 15% male, with the range of patients aged of 61-70 years of 46.67% and had history of diabetic (90%). The history of drugs consumed by respondents was anti diabetic drugs such as metformin (40%), glimepiride (33.37%) and insulin (6.67%). In addition, the increased knowledge of DM patients after being given the training compared to before training was shown in several questions in the questionnaire. A statistical analysis using t-test analyzed a correlation between training provided in order to enhance understanding of the patient, as well as correlation with blood glucose levels. A paired T-test showed that there was a relationship between the knowledge of trainees before and after training (p less than 0.05). An interesting result was that there was no relationship between blood glucose levels before and after training provided (p> 0.05).

scholarly journals Observation evidences of atmospheric Gravity Waves induced by seismic activity from analysis of subionospheric LF signal spectra

2007 ◽  
Vol 7 (5) ◽  
pp. 625-628 ◽  
Author(s):  
A. Rozhnoi ◽  
M. Solovieva ◽  
O. Molchanov ◽  
P.-F. Biagi ◽  
M. Hayakawa
Keyword(s):  
Gravity Waves ◽  
Fresnel Zone ◽  
Signal Amplitude ◽  
Magnetic Storms ◽  
Frequency Range ◽  
Atmospheric Gravity Waves ◽  
Period Range ◽  
Before And After ◽  
Atmospheric Gravity ◽  
Large Earthquakes

Abstract. We analyze variations of the LF subionospheric signal amplitude and phase from JJY transmitter in Japan (F=40 kHz) received in Petropavlovsk-Kamchatsky station during seismically quiet and active periods including also periods of magnetic storms. After 20 s averaging, the frequency range of the analysis is 0.28–15 mHz that corresponds to the period range from 1 to 60 min. Changes in spectra of the LF signal perturbations are found several days before and after three large earthquakes, which happened in November 2004 (M=7.1), August 2005 (M=7.2) and November 2006 (M=8.2) inside the Fresnel zone of the Japan-Kamchatka wavepath. Comparing the perturbed and background spectra we have found the evident increase in spectral range 10–25 min that is in the compliance with theoretical estimations on lithosphere-ionosphere coupling by the Atmospheric Gravity Waves (T>6 min). Similar changes are not found for the periods of magnetic storms.

scholarly journals Species and characteristics of volatile organic compounds emitted from an auto-repair painting workshop

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Y. Song ◽  
H. Chun
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Large Scale ◽  
Butyl Acetate ◽  
Small Scale ◽  
Indoor Environments ◽  
Voc Emissions ◽  
Volatile Organic ◽  
Before And After ◽  
Adsorption Systems

AbstractVolatile organic compounds (VOCs) are secondary pollutant precursors having adverse impacts on the environment and human health. Although VOC emissions, their sources, and impacts have been investigated, the focus has been on large-scale industrial sources or indoor environments; studies on relatively small-scale enterprises (e.g., auto-repair workshops) are lacking. Here, we performed field VOC measurements for an auto-repair painting facility in Korea and analyzed the characteristics of VOCs emitted from the main painting workshop (top coat). The total VOC concentration was 5069–8058 ppb, and 24–35 species were detected. The VOCs were mainly identified as butyl acetate, toluene, ethylbenzene, and xylene compounds. VOC characteristics differed depending on the paint type. Butyl acetate had the highest concentration in both water- and oil-based paints; however, its concentration and proportion were higher in the former (3256 ppb, 65.5%) than in the latter (2449 ppb, 31.1%). Comparing VOC concentration before and after passing through adsorption systems, concentrations of most VOCs were lower at the outlets than the inlets of the adsorption systems, but were found to be high at the outlets in some workshops. These results provide a theoretical basis for developing effective VOC control systems and managing VOC emissions from auto-repair painting workshops.

scholarly journals An Assessment of ERA5 Reanalysis for Antarctic Near-Surface Air Temperature

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 217
Author(s):  
Jiangping Zhu ◽  
Aihong Xie ◽  
Xiang Qin ◽  
Yetang Wang ◽  
Bing Xu ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Antarctic Peninsula ◽  
Austral Summer ◽  
Correlation Coefficients ◽  
East Antarctica ◽  
West Antarctica ◽  
Austral Spring ◽  
Reanalysis Dataset ◽  
Near Surface ◽  
The Antarctic

The European Center for Medium-Range Weather Forecasts (ECMWF) released its latest reanalysis dataset named ERA5 in 2017. To assess the performance of ERA5 in Antarctica, we compare the near-surface temperature data from ERA5 and ERA-Interim with the measured data from 41 weather stations. ERA5 has a strong linear relationship with monthly observations, and the statistical significant correlation coefficients (p < 0.05) are higher than 0.95 at all stations selected. The performance of ERA5 shows regional differences, and the correlations are high in West Antarctica and low in East Antarctica. Compared with ERA5, ERA-Interim has a slightly higher linear relationship with observations in the Antarctic Peninsula. ERA5 agrees well with the temperature observations in austral spring, with significant correlation coefficients higher than 0.90 and bias lower than 0.70 °C. The temperature trend from ERA5 is consistent with that from observations, in which a cooling trend dominates East Antarctica and West Antarctica, while a warming trend exists in the Antarctic Peninsula except during austral summer. Generally, ERA5 can effectively represent the temperature changes in Antarctica and its three subregions. Although ERA5 has bias, ERA5 can play an important role as a powerful tool to explore the climate change in Antarctica with sparse in situ observations.

scholarly journals Reconstruction of river valley evolution before and after the emplacement of the giant Seymareh rock avalanche (Zagros Mts., Iran)

2019 ◽  
Vol 7 (4) ◽  
pp. 929-947 ◽  
Author(s):  
Michele Delchiaro ◽  
Marta Della Seta ◽  
Salvatore Martino ◽  
Maryam Dehbozorgi ◽  
Reza Nozaem
Keyword(s):  
Slope Failure ◽  
Rock Avalanche ◽  
Evolutionary Model ◽  
River Valley ◽  
Time To Failure ◽  
Stress Release ◽  
Seismic Triggering ◽  
Rock Creep ◽  
Before And After

Abstract. The Seymareh landslide, detached ∼10 ka from the northeastern flank of the Kabir-kuh fold (Zagros Mts., Iran), is recognized worldwide as the largest rock slope failure (44 Gm3) ever recorded on the exposed Earth surface. Detailed studies have been performed that have described the landslide mechanism and different scenarios have been proposed for explaining the induced landscape changes. The purpose of this study is to provide still missing time constraints on the evolution of the Seymareh River valley, before and after the emplacement of the Seymareh landslide, to highlight the role of geomorphic processes both as predisposing factors and as response to the landslide debris emplacement. We used optically stimulated luminescence (OSL) to date lacustrine and fluvial terrace sediments, whose plano-altimetric distribution has been correlated to the detectable knickpoints along the Seymareh River longitudinal profile, allowing the reconstruction of the evolutionary model of the fluvial valley. We infer that the knickpoint migration along the main river and the erosion wave propagation upstream through the whole drainage network caused the stress release and the ultimate failure of the rock mass involved in the landslide. We estimated that the stress release activated a mass rock creep (MRC) process with gravity-driven deformation processes occurring over an elapsed time-to-failure value on the order of 102 kyr. We estimated also that the Seymareh damming lake persisted for ∼3500 years before starting to empty ∼6.6 ka due to lake overflow. A sedimentation rate of 10 mm yr−1 was estimated for the lacustrine deposits, which increased up to 17 mm yr−1 during the early stage of lake emptying due to the increased sediment yield from the lake tributaries. We calculated an erosion rate of 1.8 cm yr−1 since the initiation of dam breaching by the Seymareh River, which propagated through the drainage system up to the landslide source area. The evolutionary model of the Seymareh River valley can provide the necessary constraints for future stress–strain numerical modeling of the landslide slope to reproduce the MRC and demonstrate the possible role of seismic triggering in prematurely terminating the creep-controlled time-to-failure pathway for such an extremely large case study.

Effect of Full- and Small-Scale Reeling Simulation on Mechanical Properties of Weldable 13Cr Seamless Line Pipe

2013 ◽  
Author(s):  
Hidenori Shitamoto ◽  
Nobuyuki Hisamune
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Oil And Gas ◽  
Small Scale ◽  
Line Pipe ◽  
Offshore Pipeline ◽  
Oil And Gas Pipelines ◽  
Before And After ◽  
Offshore Oil And Gas ◽  
Offshore Oil

There are several methods currently being used to install offshore oil and gas pipelines. The reel-lay process is fast and one of the most effective offshore pipeline installation methods for seamless, ERW, and UOE line pipes with outside diameters of 18 inches or less. In the case of the reel-laying method, line pipes are subjected to plastic deformation multiplication during reel-laying. It is thus important to understand the change of the mechanical properties of line pipes before and after reel-laying. Therefore, full-scale reeling (FSR) simulations and small-scale reeling (SSR) simulations are applied as evaluation tests for reel-laying. In this study, FSR simulations were performed to investigate the effect of cyclic deformation on the mechanical properties of weldable 13Cr seamless line pipes. Furthermore, SSR simulations were performed to compare the results obtained by FSR simulations.

scholarly journals Can gravity waves significantly impact PSC occurrence in the Antarctic?

2009 ◽  
Vol 9 (22) ◽  
pp. 8825-8840 ◽  
Author(s):  
A. J. McDonald ◽  
S. E. George ◽  
R. M. Woollands
Keyword(s):  
Antarctic Peninsula ◽  
Gravity Waves ◽  
Clustering Algorithm ◽  
Small Scale ◽  
Temperature Threshold ◽  
Aerosol Extinction ◽  
Polar Stratospheric Clouds ◽  
Mountain Wave ◽  
Stratospheric Clouds ◽  
The Antarctic

Abstract. A combination of POAM III aerosol extinction and CHAMP RO temperature measurements are used to examine the role of atmospheric gravity waves in the formation of Antarctic Polar Stratospheric Clouds (PSCs). POAM III aerosol extinction observations and quality flag information are used to identify Polar Stratospheric Clouds using an unsupervised clustering algorithm. A PSC proxy, derived by thresholding Met Office temperature analyses with the PSC Type Ia formation temperature (TNAT), shows general agreement with the results of the POAM III analysis. However, in June the POAM III observations of PSC are more abundant than expected from temperature threshold crossings in five out of the eight years examined. In addition, September and October PSC identified using temperature thresholding is often significantly higher than that derived from POAM III; this observation probably being due to dehydration and denitrification. Comparison of the Met Office temperature analyses with corresponding CHAMP observations also suggests a small warm bias in the Met Office data in June. However, this bias cannot fully explain the differences observed. Analysis of CHAMP data indicates that temperature perturbations associated with gravity waves may partially explain the enhanced PSC incidence observed in June (relative to the Met Office analyses). For this month, approximately 40% of the temperature threshold crossings observed using CHAMP RO data are associated with small-scale perturbations. Examination of the distribution of temperatures relative to TNAT shows a large proportion of June data to be close to this threshold, potentially enhancing the importance of gravity wave induced temperature perturbations. Inspection of the longitudinal structure of PSC occurrence in June 2005 also shows that regions of enhancement are geographically associated with the Antarctic Peninsula; a known mountain wave "hotspot". The latitudinal variation of POAM III observations means that we only observe this region in June–July, and thus the true pattern of enhanced PSC production may continue operating into later months. The analysis has shown that early in the Antarctic winter stratospheric background temperatures are close to the TNAT threshold (and PSC formation), and are thus sensitive to temperature perturbations associated with mountain wave activity near the Antarctic peninsula (40% of PSC formation). Later in the season, and at latitudes away from the peninsula, temperature perturbations associated with gravity waves contribute to about 15% of the observed PSC (a value which corresponds well to several previous studies). This lower value is likely to be due to colder background temperatures already achieving the TNAT threshold unaided. Additionally, there is a reduction in the magnitude of gravity waves perturbations observed as POAM III samples poleward of the peninsula.

scholarly journals Monsoonal control on a delayed response of sedimentation to the 2008 Wenchuan earthquake

2019 ◽  
Vol 5 (6) ◽  
pp. eaav7110 ◽  
Author(s):  
Fei Zhang ◽  
Zhangdong Jin ◽  
A. Joshua West ◽  
Zhisheng An ◽  
Robert G. Hilton ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Transport Processes ◽  
Delayed Response ◽  
2008 Wenchuan Earthquake ◽  
The 2008 Wenchuan Earthquake ◽  
Depositional Processes ◽  
Before And After ◽  
Sediment Transfer ◽  
Large Earthquakes ◽  
Earthquake Cycles

Infrequent extreme events such as large earthquakes pose hazards and have lasting impacts on landscapes and biogeochemical cycles. Sediments provide valuable records of past events, but unambiguously identifying event deposits is challenging because of nonlinear sediment transport processes and poor age control. Here, we have been able to directly track the propagation of a tectonic signal into stratigraphy using reservoir sediments from before and after the 2008 Wenchuan earthquake. Cycles in magnetic susceptibility allow us to define a precise annual chronology and identify the timing and nature of the earthquake’s sedimentary record. The grain size and Rb/Sr ratio of the sediments responded immediately to the earthquake. However, the changes were muted until 2 years after the event, when intense monsoonal runoff drove accumulation of coarser grains and lower Rb/Sr sediments. The delayed response provides insight into how climatic and tectonic agents interact to control sediment transfer and depositional processes.

Efficiency and selectivity of the Anomalocardia brasiliana (Mollusca: Veneridae) hand dredge used in southern Brazil

2010 ◽  
Vol 90 (7) ◽  
pp. 1455-1464 ◽  
Author(s):  
Paulo R. Pezzuto ◽  
Caroline Schio ◽  
Tito C.M. Almeida
Keyword(s):  
Management Plan ◽  
Fishing Effort ◽  
Management Tool ◽  
Small Scale ◽  
Commercial Fisheries ◽  
Effective Management ◽  
Southern Brazil ◽  
Fishing Rights ◽  
Before And After ◽  
Experimental Plots

In Florianópolis, southern Brazil, the venerid clam Anomalocardia brasiliana has supported subsistence and small-scale commercial fisheries for decades. The introduction of a hand dredge (gancho) since 1987 led to the development of a significant fishery supplying both local and regional shellfish markets. In 1992 one of the main fishing areas in the region was designated as the first Brazilian Marine Extractive Reserve (Pirajubaé RESEX), a federal form of governance intended to promote sustainable exploitation of natural resources by assigning exclusive fishing rights to traditional users. However, excessive fishing effort, institutional shortcomings and lack of a negotiated management plan have resulted in the overexploitation of the species since 2000. This study was aimed at evaluating the efficiency and selectivity of the hand dredge currently in use at the RESEX, through a field experiment conducted in October 2006. Quantitative samples of A. brasiliana were collected before and after dredging 15 experimental plots. Additional samples were obtained inside the dredge (catch) and respective cover cod-end (discard) for selectivity analysis. A single haul of the hand dredge can dislocate up to 76% of the individuals present in the sediment irrespective of their size, and retain up to 69% of the commercial-sized organisms. The gear has a knife-edge selection pattern, which enables the use of the minimum spacing between the iron bars of the dredge's basket as an effective management tool.

scholarly journals The Osservatorio Geofisico Sperimentale marine magnetic surveys in the Antarctic Seas

1999 ◽  
Vol 42 (2) ◽  
Author(s):  
E. Lodolo ◽  
F. Coren ◽  
C. Zanolla
Keyword(s):  
Tectonic Evolution ◽  
Ross Sea ◽  
Austral Summer ◽  
Geological Structure ◽  
Seismic Profiles ◽  
Scotia Sea ◽  
Geophysical Surveys ◽  
Scientific Results ◽  
The Antarctic ◽  
Derived Data

About 40 000 km of marine magnetic and gradiometric data have been collected during eight geophysical surveys conducted since the Austral summer 1987/1988 in the circum-antarctic seas, by the research vessel OGS-Explora. For the most surveyed areas (Ross Sea, Southwestern Pacific Ocean, and Southern Scotia Sea), the analysis of the acquired data have contributed to clarify important aspects of their geological structure and tectonic evolution. The main scientific results, obtained combining other available geophysical data (multichannel seismic profiles and satellite-derived data), will be briefly illustrated.

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