scholarly journals InSAR Constrained Downdip and Updip Afterslip Following the 2015 Nepal Earthquake: New Insights into Moment Budget of the Main Himalayan Thrust

2022 ◽  
Vol 14 (2) ◽  
pp. 306
Author(s):  
Lei Zhao ◽  
Chunyan Qu ◽  
Dezheng Zhao ◽  
Xinjian Shan ◽  
Han Chen ◽  
...  
Keyword(s):  
Large Scale ◽  
Average Rate ◽  
Deformation Field ◽  
First Year ◽  
Nepal Earthquake ◽  
The North ◽  
Subsidence Area ◽  
Seismic Deformation ◽  
Frictional Slip ◽  
Uplift Deformation

We use ALOS-2 and Sentinel-1 data spanning 2015-2020 to obtain the post-seismic deformation of the 2015 Mw 7.8 Nepal earthquake. ALOS-2 observations reveal that the post-seismic deformation was mainly distributed in four areas. A large-scale uplift deformation occurred in the northern subsidence area of the co-seismic deformation field, with a maximum uplift of ~80mm within 4.5 yr after the mainshock. While in the southern coseismic uplift area, the direction of the post-seismic deformation is generally opposite to the co-seismic deformation. Additionally, two notable deformation areas are located in the region around 29°N, and near the MFT, respectively. Sentinel-1 observations reveal post-seismic uplift deformation on the north side of the co-seismic deformation field with an average rate of ~20 mm/yr in line-of-stght. The kinematic afterslip constrained by InSAR data shows that the frictional slip is distributed in both updip and downdip areas. The maximum cumulative afterslip is 0.35 m in downdip areas, and 0.2 m in the updip areas, constrained by the ALOS measurements. The stress-driven afterslip model shows that the afterslip is distributed in the downdip area with a maximum slip of 0.3m during the first year after the earthquake. Within the 4.5 years after the mainshock, the estimated moment released by afterslip is ~1.5174 × 1020 Nm,about 21.2% of that released by the main earthquake.

scholarly journals Barotropic Regeneration of Upper-Level Synoptic Disturbances in Different Configurations of the Zonal Weather Regime

2008 ◽  
Vol 65 (10) ◽  
pp. 3159-3178 ◽  
Author(s):  
Gwendal Rivière
Keyword(s):  
Large Scale ◽  
Deformation Field ◽  
Regeneration Process ◽  
Barotropic Model ◽  
Weather Regime ◽  
The North ◽  
The Difference ◽  
Upper Level ◽  
Composite Maps ◽  
Large Scale Flow

Barotropic dynamics of upper-tropospheric midlatitude disturbances evolving in different configurations of the zonal weather regime (i.e., in different zonal-like large-scale flows) were studied using observational analyses and barotropic model experiments. The contraction stage of upper-level disturbances that follows their elongation stage leads to an increase of eddy kinetic energy that is called the barotropic regeneration process in this text. This barotropic mechanism is studied through notions of barotropic critical regions (BtCRs) and effective deformation that have been introduced in a previous paper. The effective deformation field is equal to the difference between the square of the large-scale deformation magnitude and the square of the large-scale vorticity. Regions where the effective deformation is positive correspond to regions where the large-scale flow tends to strongly stretch synoptic disturbances. A BtCR is an area separating two large-scale regions of positive effective deformation, one located upstream and on the south side of the jet and the other downstream and on the north side. Such a region presents a discontinuity in the orientation of the dilatation axes and is a potential area where the barotropic regeneration process may occur. Winter days presenting a zonal weather regime in the 40-yr ECMWF Re-Analysis dataset are decomposed, via a partitioning algorithm, into different configurations of the effective deformation field at 300 hPa. A six-cluster partition is obtained. Composite maps of the barotropic generation rate for each cluster exhibit a succession of negative and positive values on both sides of the BtCRs. It confirms statistically that the barotropic regeneration mechanism occurs preferentially about BtCRs. Numerical experiments using a forced barotropic model on the sphere are performed. Each experiment consists of adding a synoptic-scale perturbation to one of the zonal-like jet configurations found in observations, which is kept fixed with time. The combined effects of the effective deformation and nonlinearities are shown to be crucial to reproduce the barotropic regeneration process about BtCRs.

scholarly journals Subsidence and carbon loss in drained tropical peatlands

2012 ◽  
Vol 9 (3) ◽  
pp. 1053-1071 ◽  
Author(s):  
A. Hooijer ◽  
S. Page ◽  
J. Jauhiainen ◽  
W. A. Lee ◽  
X. X. Lu ◽  
...  
Keyword(s):  
Water Table ◽  
Land Subsidence ◽  
Large Scale ◽  
Average Rate ◽  
Water Levels ◽  
First Year ◽  
Carbon Loss ◽  
Long Term Storage ◽  
Tropical Peatlands ◽  
Average Loss

Abstract. Conversion of tropical peatlands to agriculture leads to a release of carbon from previously stable, long-term storage, resulting in land subsidence that can be a surrogate measure of CO2 emissions to the atmosphere. We present an analysis of recent large-scale subsidence monitoring studies in Acacia and oil palm plantations on peatland in SE Asia, and compare the findings with previous studies. Subsidence in the first 5 yr after drainage was found to be 142 cm, of which 75 cm occurred in the first year. After 5 yr, the subsidence rate in both plantation types, at average water table depths of 0.7 m, remained constant at around 5 cm yr−1. The results confirm that primary consolidation contributed substantially to total subsidence only in the first year after drainage, that secondary consolidation was negligible, and that the amount of compaction was also much reduced within 5 yr. Over 5 yr after drainage, 75 % of cumulative subsidence was caused by peat oxidation, and after 18 yr this was 92 %. The average rate of carbon loss over the first 5 yr was 178 t CO2eq ha−1 yr−1, which reduced to 73 t CO2eq ha−1 yr−1 over subsequent years, potentially resulting in an average loss of 100 t CO2eq ha−1 yr−1 over 25 yr. Part of the observed range in subsidence and carbon loss values is explained by differences in water table depth, but vegetation cover and other factors such as addition of fertilizers also influence peat oxidation. A relationship with groundwater table depth shows that subsidence and carbon loss are still considerable even at the highest water levels theoretically possible in plantations. This implies that improved plantation water management will reduce these impacts by 20 % at most, relative to current conditions, and that high rates of carbon loss and land subsidence are inevitable consequences of conversion of forested tropical peatlands to other land uses.

scholarly journals Time-Variable Refraction of the Internal Tide at the Hawaiian Ridge

2014 ◽  
Vol 44 (2) ◽  
pp. 538-557 ◽  
Author(s):  
Edward D. Zaron ◽  
Gary D. Egbert
Keyword(s):  
Large Scale ◽  
Initial Conditions ◽  
Average Rate ◽  
Internal Tide ◽  
Tidal Energy ◽  
Ocean Model ◽  
The North ◽  
Scattering Rate ◽  
Hawaiian Ridge ◽  
Background Fields

Abstract The interaction of the dominant semidiurnal M2 internal tide with the large-scale subtidal flow is examined in an ocean model by propagating the tide through an ensemble of background fields in a domain centered on the Hawaiian Ridge. The background fields are taken from the Simple Ocean Data Assimilation (SODA) ocean analysis, at 2-month intervals from 1992 through 2001. Tides are computed with the Primitive Equation Z-coordinate Harmonic Analysis of Tides (PEZ-HAT) model by 14-day integrations using SODA initial conditions and M2 tidal forcing. Variability of the tide is found to occur primarily as the result of propagation through the nonstationary background fields, rather than via generation site variability. Generation of incoherent tidal variability is mapped and shown to occur mostly in association with waves generated at French Frigate Shoals scattering near the Musicians Seamounts to the north of the ridge. The phase-coherent internal tide loses energy at a domain-average rate of 2 mW m−2 by scattering into the nonstationary tide. Because of the interference of waves from multiple generation sites, variability of the internal tide is spatially inhomogeneous and values of the scattering rate 10 times larger occur in localized areas. It is estimated that 20% of the baroclinic tidal energy flux is lost by adiabatic scattering (refraction) within 250 km of the ridge, a value regarded as a lower bound because of the smoothed nature of the SODA fields used in this study.

scholarly journals InSAR 3-D Coseismic Displacement Field of the 2015 Mw 7.8 Nepal Earthquake: Insights into Complex Fault Kinematics during the Event

2020 ◽  
Vol 12 (23) ◽  
pp. 3982
Author(s):  
Chunyan Qu ◽  
Xin Qiao ◽  
Xinjian Shan ◽  
Dezheng Zhao ◽  
Lei Zhao ◽  
...  
Keyword(s):  
Surface Deformation ◽  
Three Dimensional ◽  
Deformation Field ◽  
Coseismic Deformation ◽  
Maximum Displacement ◽  
Nepal Earthquake ◽  
The North ◽  
Complex Fault ◽  
Fault Kinematics ◽  
East West

The 2015 Mw 7.8 Gorkha, Nepal, earthquake occurred in the central Himalayan collisional orogenic belt, which demonstrated complex fault kinematics and significant surface deformation. The coseismic deformation has been well documented by previous studies using Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data. However, due to some limitations of spatially sparse GPS stations and InSAR only-one-dimensional observation in the line-of-sight (LOS) direction, the complete distribution and detailed spatial variation of the three-dimensional surface deformation field are still not fully understood. In this study, we reconstructed the three-dimensional coseismic deformation fields using multi-view InSAR observations and investigated the refined surface deformation characteristics during this event. We firstly obtained four ascending and descending InSAR coseismic deformation maps from both Sentinel-1A/B and ALOS-2 data. Secondly, we obtained the synthetic north-south deformation field from our best-fitting slip distribution inversions. Finally, we calculated three-dimensional deformation fields, which were consistent with coseismic GPS displacements but with higher resolution. We found that the surface deformation is dominated by horizontal southward motion and vertical uplift and subsidence, with minor east-west deformation. In the north-south direction, the whole deformation area reaches at least 150 × 150 km with a maximum displacement of ~1.5 m. In the vertical direction, two areas, including uplift in the south and subsidence in the north, are mapped with a peak displacement of 1.5 and −1.0 m, respectively. East-west deformation presented a four-quadrant distribution with a maximum displacement of ~0.6 m. Complex thrusting movement occurred on the seismogenic fault; overall, there was southward push motion and wave-shaped fold motion.

scholarly journals Subsidence and carbon loss in drained tropical peatlands: reducing uncertainty and implications for CO<sub>2</sub> emission reduction options

2011 ◽  
Vol 8 (5) ◽  
pp. 9311-9356 ◽  
Author(s):  
A. Hooijer ◽  
S. Page ◽  
J. Jauhiainen ◽  
W. A. Lee ◽  
X. X. Lu ◽  
...  
Keyword(s):  
Water Table ◽  
Land Subsidence ◽  
Large Scale ◽  
Average Rate ◽  
First Year ◽  
Carbon Loss ◽  
Long Term Storage ◽  
Tropical Peatlands ◽  
Average Loss ◽  
Subsidence Monitoring

Abstract. Conversion of tropical peatlands to agriculture leads to a release of carbon from previously stable, long-term storage, resulting in land subsidence that can be a surrogate measure of CO2 emissions to the atmosphere. We present an analysis of recent large-scale subsidence monitoring studies in Acacia and oil palm plantations on peatland in SE Asia, and compare the findings with previous studies. Subsidence in the first 5 years after drainage was found to be 142 cm, of which 75 cm occurred in the first year. After 5 years, the subsidence rate in both plantation types, at average water table depths of 0.7 m, remained constant at around 5 cm yr−1. Bulk density profiles indicate that consolidation contributes only 7 % to total subsidence, in the first year after drainage, and that the role of compaction is also reduced quickly and becomes negligible after 5 years. Over 18 years after drainage, 92 % of cumulative subsidence was caused by peat oxidation. The average rate of carbon loss over the first 5 years was 178 t ha−1 yr−1 CO2eq, which reduced to 73 t ha−1 yr−1 CO2eq over subsequent years, resulting in an average loss of 100 t ha−1 yr−1 CO2eq annualized over 25 years. Part of the observed range in subsidence and carbon loss values is explained by differences in water table depth, but vegetation cover and addition of fertilizers also influence peat oxidation. A relationship with groundwater table depth shows that subsidence and carbon loss are still considerable even at the highest water table levels theoretically possible in plantations. This implies that improved water management will reduce these impacts by only 20 % at most, relative to current conditions, and that high rates of carbon loss and land subsidence should be accepted as inevitable consequences of conversion of forested tropical peatlands to other land uses.

Why Has There Been No People’s Power Rebellion in North Korea?

2018 ◽  
pp. 1-34
Author(s):  
Andrew Jackson
Keyword(s):  
Rural Areas ◽  
North Korea ◽  
Large Scale ◽  
Political Elite ◽  
Information Control ◽  
Al Jazeera ◽  
The North ◽  
New Information ◽  
Effective System ◽  
The Right

One scenario put forward by researchers, political commentators and journalists for the collapse of North Korea has been a People’s Power (or popular) rebellion. This paper analyses why no popular rebellion has occurred in the DPRK under Kim Jong Un. It challenges the assumption that popular rebellion would happen because of widespread anger caused by a greater awareness of superior economic conditions outside the DPRK. Using Jack Goldstone’s theoretical expla-nations for the outbreak of popular rebellion, and comparisons with the 1989 Romanian and 2010–11 Tunisian transitions, this paper argues that marketi-zation has led to a loosening of state ideological control and to an influx of infor-mation about conditions in the outside world. However, unlike the Tunisian transitions—in which a new information context shaped by social media, the Al-Jazeera network and an experience of protest helped create a sense of pan-Arab solidarity amongst Tunisians resisting their government—there has been no similar ideology unifying North Koreans against their regime. There is evidence of discontent in market unrest in the DPRK, although protests between 2011 and the present have mostly been in defense of the right of people to support themselves through private trade. North Koreans believe this right has been guaranteed, or at least tacitly condoned, by the Kim Jong Un government. There has not been any large-scale explosion of popular anger because the state has not attempted to crush market activities outright under Kim Jong Un. There are other reasons why no popular rebellion has occurred in the North. Unlike Tunisia, the DPRK lacks a dissident political elite capable of leading an opposition movement, and unlike Romania, the DPRK authorities have shown some flexibility in their anti-dissent strategies, taking a more tolerant approach to protests against economic issues. Reduced levels of violence during periods of unrest and an effective system of information control may have helped restrict the expansion of unrest beyond rural areas.

Information And Map-Made Control With The Functions Of Business Analytics For Urban Management

2019 ◽  
pp. 72-78
Keyword(s):  
Large Scale ◽  
Information Support ◽  
Urban Management ◽  
Business Analytics ◽  
Administrative District ◽  
The North ◽  
Model Of Management ◽  
Complex Development ◽  
Coordination System ◽  
Key Aspects

The key aspects of the process of designing and developing an information and cartographic control tool with business analytics functions for the municipal level of urban management are considered. The review of functionality of the developed tool is given. Examples of its use for the analysis and monitoring of implementation of the program of complex development of territories are given. The importance of application of information support of management and coordination at all levels of management as an integral part of the basic model of management and coordination system of large-scale urban projects of dispersed construction is proved. Information and map-made tool with business intelligence functions was used and was highly appreciated in the preparation of information-analytical and presentation materials of the North-Eastern Administrative District of Moscow. Its use made it possible to significantly optimize the list of activities of the program of integrated development of territories, their priority and timing.

DESIGN AND IMPLEMENTATION OF THE OCEANOGRAPHIC MODELING AND OBSERVATION NETWORK (REMO) FOR PHYSICAL OCEANOGRAPHY STUDIES AND OCEAN FORECASTING

2014 ◽  
Vol 31 (2) ◽  
Author(s):  
Jose Antonio Moreira Lima
Keyword(s):  
Atlantic Ocean ◽  
Large Scale ◽  
North Pacific Ocean ◽  
Integrated Approach ◽  
Sea Surface ◽  
Global Ocean ◽  
Height Anomaly ◽  
The North ◽  
Observation Network ◽  
Ocean Forecasting

This paper is concerned with the planning, implementation and some results of the Oceanographic Modeling and Observation Network, named REMO, for Brazilian regional waters. Ocean forecasting has been an important scientific issue over the last decade due to studies related to climate change as well as applications related to short-range oceanic forecasts. The South Atlantic Ocean has a deficit of oceanographic measurements when compared to other ocean basins such as the North Atlantic Ocean and the North Pacific Ocean. It is a challenge to design an ocean forecasting system for a region with poor observational coverage of in-situ data. Fortunately, most ocean forecasting systems heavily rely on the assimilation of surface fields such as sea surface height anomaly (SSHA) or sea surface temperature (SST), acquired by environmental satellites, that can accurately provide information that constrain major surface current systems and their mesoscale activity. An integrated approach is proposed here in which the large scale circulation in the Atlantic Ocean is modeled in a first step, and gradually nested into higher resolution regional models that are able to resolve important processes such as the Brazil Current and associated mesoscale variability, continental shelf waves, local and remote wind forcing, and others. This article presents the overall strategy to develop the models using a network of Brazilian institutions and their related expertise along with international collaboration. This work has some similarity with goals of the international project Global Ocean Data Assimilation Experiment OceanView (GODAE OceanView).

scholarly journals Impact of air–sea coupling on the climate change signal over the Iberian Peninsula

2021 ◽  
Author(s):  
Alba de la Vara ◽  
William Cabos ◽  
Dmitry V. Sein ◽  
Claas Teichmann ◽  
Daniela Jacob
Keyword(s):  
Climate Change ◽  
Iberian Peninsula ◽  
Mediterranean Sea ◽  
Large Scale ◽  
Regional Distribution ◽  
Coupled Model ◽  
Climate Change Signal ◽  
The North ◽  
The Mediterranean ◽  
The Impact

AbstractIn this work we use a regional atmosphere–ocean coupled model (RAOCM) and its stand-alone atmospheric component to gain insight into the impact of atmosphere–ocean coupling on the climate change signal over the Iberian Peninsula (IP). The IP climate is influenced by both the Atlantic Ocean and the Mediterranean sea. Complex interactions with the orography take place there and high-resolution models are required to realistically reproduce its current and future climate. We find that under the RCP8.5 scenario, the generalized 2-m air temperature (T2M) increase by the end of the twenty-first century (2070–2099) in the atmospheric-only simulation is tempered by the coupling. The impact of coupling is specially seen in summer, when the warming is stronger. Precipitation shows regionally-dependent changes in winter, whilst a drier climate is found in summer. The coupling generally reduces the magnitude of the changes. Differences in T2M and precipitation between the coupled and uncoupled simulations are caused by changes in the Atlantic large-scale circulation and in the Mediterranean Sea. Additionally, the differences in projected changes of T2M and precipitation with the RAOCM under the RCP8.5 and RCP4.5 scenarios are tackled. Results show that in winter and summer T2M increases less and precipitation changes are of a smaller magnitude with the RCP4.5. Whilst in summer changes present a similar regional distribution in both runs, in winter there are some differences in the NW of the IP due to differences in the North Atlantic circulation. The differences in the climate change signal from the RAOCM and the driving Global Coupled Model show that regionalization has an effect in terms of higher resolution over the land and ocean.

scholarly journals Phylogeography in an “oyster” shell provides first insights into the genetic structure of an extinct Ostrea edulis population

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah Hayer ◽  
Dirk Brandis ◽  
Alexander Immel ◽  
Julian Susat ◽  
Montserrat Torres-Oliva ◽  
...  
Keyword(s):  
Large Scale ◽  
Wadden Sea ◽  
Atlantic Coast ◽  
Phylogenetic Reconstruction ◽  
Oyster Shell ◽  
Glacial Refugia ◽  
Late Nineteenth Century ◽  
Ostrea Edulis ◽  
Geographic Ranges ◽  
The North

AbstractThe historical phylogeography of Ostrea edulis was successfully depicted in its native range for the first time using ancient DNA methods on dry shells from museum collections. This research reconstructed the historical population structure of the European flat oyster across Europe in the 1870s—including the now extinct population in the Wadden Sea. In total, four haplogroups were identified with one haplogroup having a patchy distribution from the North Sea to the Atlantic coast of France. This irregular distribution could be the result of translocations. The other three haplogroups are restricted to narrow geographic ranges, which may indicate adaptation to local environmental conditions or geographical barriers to gene flow. The phylogenetic reconstruction of the four haplogroups suggests the signatures of glacial refugia and postglacial expansion. The comparison with present-day O. edulis populations revealed a temporally stable population genetic pattern over the past 150 years despite large-scale translocations. This historical phylogeographic reconstruction was able to discover an autochthonous population in the German and Danish Wadden Sea in the late nineteenth century, where O. edulis is extinct today. The genetic distinctiveness of a now-extinct population hints at a connection between the genetic background of O. edulis in the Wadden Sea and for its absence until today.

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