A Two-Scale Preparation Phase Preceded an Mw 5.8 Earthquake in the Sea of Marmara Offshore Istanbul, Turkey

2020 ◽  
Vol 91 (6) ◽  
pp. 3139-3147 ◽  
Author(s):  
Virginie Durand ◽  
Stephan Bentz ◽  
Grzegorz Kwiatek ◽  
Georg Dresen ◽  
Christopher Wollin ◽  
...  
Keyword(s):  
Matched Filter ◽  
Aseismic Slip ◽  
Sea Of Marmara ◽  
Spatiotemporal Evolution ◽  
Short Term ◽  
Filter Technique ◽  
The North ◽  
Preparation Phase ◽  
Scale Preparation

Abstract We analyze the spatiotemporal evolution of seismicity during a sequence of moderate (an Mw 4.7 foreshock and Mw 5.8 mainshock) earthquakes occurring in September 2019 at the transition between a creeping and a locked segment of the North Anatolian fault in the central Sea of Marmara, northwest Turkey. To investigate in detail the seismicity evolution, we apply a matched-filter technique to continuous waveforms, thus reducing the magnitude threshold for detection. Sequences of foreshocks preceding the two largest events are clearly seen, exhibiting two different behaviors: a long-term activation of the seismicity along the entire fault segment and a short-term concentration around the epicenters of the large events. We suggest a two-scale preparation phase, with aseismic slip preparing the mainshock final rupture a few days before, and a cascade mechanism leading to the nucleation of the mainshock. Thus, our study shows a combination of seismic and aseismic slip during the foreshock sequence changing the strength of the fault, bringing it closer to failure.

Analysis of the foreshock sequences preceding two moderate (Mw4.7 and Mw5.8) earthquakes in the Sea of Marmara offshore Istanbul, Turkey.

2020 ◽  
Author(s):  
Virginie Durand ◽  
Stephan Bentz ◽  
Grzegorz Kwiatek ◽  
Georg Dresen ◽  
Christopher Wollin ◽  
...  
Keyword(s):  
Stress State ◽  
Matched Filter ◽  
Preparation Process ◽  
Aseismic Slip ◽  
Sea Of Marmara ◽  
Spatiotemporal Evolution ◽  
Short Term ◽  
Filter Technique ◽  
The North

<p>In September 2019 a sequence of two moderate earthquakes (Mw4.7 and Mw5.8) occurred in the central Sea of Marmara (Turkey), SW of Istanbul. These events took place ate the transition between a creeping and a locked segment of the North Anatolian Fault. To investigate in detail the spatiotemporal evolution of the seismicity, we apply a matched-filter technique to continuous waveforms, thus reducing the magnitude threshold for detection. Sequences of foreshocks preceding the two mainshocks are clearly seen, exhibiting different behaviors: a migration of the seismicity along the entire fault segment on the long-term (several days before the mainshocks) and a concentration around the epicenters of the large events on the short-term (during the few hours preceding the mainshocks). We infer that both seismic and aseismic slip during the foreshock sequences change the stress state on the fault, bringing it closer to failure. Our observations also suggest that the Mw 4.7 event contributed to weaken the fault as part of the preparation process of the Mw 5.8 earthquake.</p>

scholarly journals Very early identification of a bimodal frictional behavior during the post-seismic phase of the 2015 M<sub><i>w</i></sub>8.3 Illapel, Chile, earthquake

2021 ◽  
Author(s):  
Cedric Twardzik ◽  
Mathilde Vergnolle ◽  
Anthony Sladen ◽  
Louisa L. H. Tsang
Keyword(s):  
Template Matching ◽  
State Of The Art ◽  
Data Driven ◽  
Spatiotemporal Evolution ◽  
Seismic Slip ◽  
The North ◽  
Chile Earthquake ◽  
Gnss Data ◽  
Matching Techniques

Abstract. It is well-established that the post-seismic slip results from the combined contribution of seismic slip and aseismic slip. However, the partitioning between these two modes of slip remains unclear due to the difficulty to infer detailed and robust descriptions of how both evolve in space and time. This is particularly true just after a mainshock when both processes are expected to be the strongest. Using state-of-the-art sub-daily processing of GNSS data, along with dense catalogs of aftershocks obtained from template-matching techniques, we unravel the spatiotemporal evolution of post-seismic slip and aftershocks over the first 12 hours following the 2015 Mw8.3 Illapel, Chile, earthquake. We show that the very early post-seismic activity occurs over two regions with distinct behaviors. To the north, post-seismic slip appears to be purely aseismic and precedes the occurrence of late aftershocks. To the south, aftershocks are the primary cause of the post-seismic slip. We suggest that this difference in behavior could be inferred only few hours after the mainshock, and thus could contribute to a more data-driven forecasts of long-term aftershocks.

Coastal climatology of the North-Western Mediterranean area for long-term and short-term risk assessment.

2020 ◽  
Author(s):  
Carlo Brandini ◽  
Stefano Taddei ◽  
Valentina Vannucchi ◽  
Michele Bendoni ◽  
Bartolomeo Doronzo ◽  
...  
Keyword(s):  
Risk Assessment ◽  
High Resolution ◽  
Mediterranean Area ◽  
Western Mediterranean ◽  
Climate Trends ◽  
Short Term ◽  
The North ◽  
The Mediterranean ◽  
North Western

&lt;p&gt;In this work we present the results obtained through a dynamic downscaling of the ERA5 reanalysis dataset (hindcast) of ECMWF, using high-resolution meteorological and wave models defined on unstructured computation grids along the Mediterranean coasts, with a particular focus on the North-Western Mediterranean area. Downscaling of the ERA5 meteorological data is obtained through the BOLAM and MOLOCH models (up to a resolution of 2.5 km) which force an unstructured WW3 model with a resolution of up to 500 m along the coast. Models were validated through available meteorological stations, wave buoy data and X-band wave radars, the latter for the purposes of wave spectra validation.&lt;/p&gt;&lt;p&gt;On the one hand, this allowed, by extracting the time series of some attack parameters of the waves along the coast, and according to the type of coast (rocky coasts, sandy coasts, coastal structures etc.), to compute the return periods and to characterize the impact of any individual storm.&amp;#160;On the other hand, it is possible to highlight some trends observed in the last 30 years, during which recent research is showing an increasing evidence &amp;#160;of some changes in global circulation at regional to local scales. These changes also include effects of wind rotation, wave regimes, storm surges, wave-induced coastal currents and coastal morphodynamics. For example, in the North-Western Mediterranean extreme events belonging to cyclonic weather-types circulation with stronger S-SE components (like the storm of October 28-30th 2018 and many others), rather than events associated with perturbations of Atlantic origin and zonal circulation, are becoming more frequent. These long-term wind/wave climate trends can have consequences not only in the assessment of long-term risk due to main morphodynamic variations (ie. coastal erosion), but also in the short-term risk assessment.&lt;/p&gt;&lt;p&gt;This work was funded by the EU MAREGOT project (2017-2020) and ECMWF Special Project spitbran &amp;#160;&amp;#8220;Evaluation of coastal climate trends in the Mediterranean area by means of high-resolution and multi-model downscaling of ERA5 reanalysis&amp;#8221; (2018-2020).&lt;/p&gt;

scholarly journals Detection of Deep Low-frequency Earthquakes in the Nankai Subduction Zoneover 11 Years Usingamatched Filter Technique

2020 ◽  
Author(s):  
Aitaro Kato ◽  
Shigeki Nakagawa
Keyword(s):  
Matched Filter ◽  
Low Frequency ◽  
Slow Slip ◽  
Slow Slip Events ◽  
Filter Technique ◽  
Strike Direction ◽  
Episodic Tremor And Slip ◽  
Spatio Temporal ◽  
Episodic Tremor

Abstract To improve our understanding of the long-term behavior of low-frequency earthquakes (LFEs) along the tremor belt of the Nankai subduction zone, we applied a matched filter technique to continuous seismic data recorded by a dense and highly sensitive seismic network over an 11year window, April 2004 to August 2015. We detected a total of ~510,000 LFEs, or ~23× the number of LFEs in the JMA catalog for the same period. During long-term slow slip events (SSEs) in the Bungo Channel, a series of migrating LFEbursts intermittently occurred along the fault-strike direction, with slow hypocenter propagation. Elastic energy released by long-term SSEs appears to control the extent of LFE activity. We identify slowlymigrating fronts of LFEs during major episodic tremor and slip (ETS)events, which extend over distances of up to 100 km and follow diffusion-like patterns of spatial evolution with a diffusion coefficient of ~104 m2/s. This migration pattern closely matches the spatio-temporal evolution of tectonictremors reported by previous studies. At shorter distances, up to 15 km, we discovered rapid diffusion-like migrationof LFEs with a coefficient of ~105 m2/s. We also recognize that rapid migration of LFEs occurred intermittently in many streaks during major ETS episodes. These observations suggest that slow slip transients contain a multitude of smaller, temporally clustered fault slip events whose evolution is controlled by a diffusional process.

scholarly journals Exploring the Health Case for Universal Basic Income: Evidence from GPs Working with Precarious Groups

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Matthew Johnson ◽  
Dan Degerman ◽  
Robert Geyer
Keyword(s):  
Clinical Experience ◽  
Welfare Recipients ◽  
Potential Contribution ◽  
Basic Income ◽  
Short Term ◽  
North East ◽  
The North ◽  
Low Levels ◽  
Patient Side

Abstract This article draws upon clinical experience of GPs working in a deprived area of the North East of England to examine the potential contribution of Universal Basic Income to health by mitigating ‘patient-side barriers’ among three cohorts experiencing distinct forms of ‘precariousness’: 1) long-term unemployed welfare recipients with low levels of education (lumpenprecariat); 2) workers on short-term/zero-hours contracts with low levels of education (‘lower’ precariat); 3) workers on short-term/zero-hours contracts with relatively high levels of education (‘upper’ precariat). We argue that any benefits must be accompanied by robust institutions capable of promoting health.

scholarly journals PENGOPERASIAN JARING ARAD DI PERAIRAN PANTAI UTARA JAWA: MASALAH DAN PENYELESAIANNYA

2017 ◽  
Vol 4 (1) ◽  
pp. 81
Author(s):  
Ratna Indrawasih ◽  
Ary Wahyono
Keyword(s):  
Social Economic ◽  
Daily Life ◽  
Qualitative Approach ◽  
North Coast ◽  
Social Phenomenon ◽  
Short Term ◽  
The North ◽  
Central Java ◽  
Long Term Impact

Artikel tentang pengoperasian jaring arad di perairan Pantai Utara Jawa: problem dan penyelesaiannya ini membahas masalah konflik kenelayanan, terutama permasalahan yang berkaitan dengan penggunaan jaring arad di perairan Pantai Utara Jawa Tengah dan Jawa Barat. Artikel ini merupakan hasil penelitian yang mengambil lokasi di Kabupaten Rembang dan Cirebon. Penelitian tersebut dilakukan dengan pendekatan kualitatif. Hasil penelitian menunjukkan penangkapan udang dengan menggunakan jaring semi trawl merupakan suatu fenomena sosial yang menunjukkan tidak ada alternatif lain bagi nelayan dalam mencari sumber kehidupan. Fenomena ini juga menunjukkan telah terjadi jalan pintas dan bersifat jangka pendek tanpa melihat dampak-dampak yang ditimbulkan baik dari segi sosial, ekonomi dan lingkungan. Upaya untuk mengatasi problem penggunaan jaring arad di Pantura tampaknya tidak mudah. Pemerintah telah mengeluarkan peraturan yang melarang penggunaan jaring arad. Akan tetapi tampaknya kebijakan pelarangan alat tangkap tersebut menghadapi masalah pada implementasi di lapangan. Penegakan hukum belum bisa dilakukan secara optimal. Hal ini antara lain disebabkan masih pasifnya para petugas dalam mengontrol terjadinya pelanggaran, dan keberadaan petugas tidak didukung oleh prasarana yang memadai. Jadi ada kesan bahwa pelarangan alat tangkap tersebut tidak mendapat dukungan dari aparat penegak hukum, sehingga masalah yang berkaitan dengan penggunaan alat tangkap yang sudah dilarang tersebut tidak dapat terselesaikan secara tuntas. Tittle: The Operation of Arad Net in The North Coast of Java: Problems and Their Solutions.The article of “The Operation of Arad Net in The North Coast of Java: Problems and their Solution” discusses the problem of fishers conflict especially related to the usage of arad net in North Coast of Central Java and West Java. This article was conducted in Rembang and Cirebon Regencies. Qualitative approach was used in the research. Results showed that the exploitation of shrimps using a semi-trawl called ‘jaring arad’ was considered a social phenomenon of fishing to cope daily life. This phenomenon also shows that there was a short term profit orientation without considering long-term impact on social, economic and environment aspects. The effort to reduce the used of arad in Pantura was not easy. Government has erected the regulation on banning the used of arad. However, low enforcement was quite weak. This is because the officer could not effectively control territory and was not supported by adequate infrastructure and equipments. That is why, it seemed that regulation on banning the use of arad was not supported by adequate enforcement efforts. Hence, problem related the use of Arad could not be solved effectively.

scholarly journals Analysis of Effects of Economic Growth, Human Development Index, Population, Unemployment and Investment on Poverty Levels in the North Sumatra Province

2021 ◽  
Vol 8 (12) ◽  
pp. 663-685
Author(s):  
Marisa Br Sinuraya ◽  
Raina Linda Sari ◽  
Irsad Lubis
Keyword(s):  
Economic Growth ◽  
Human Development ◽  
Human Development Index ◽  
Short Term ◽  
Development Index ◽  
The North ◽  
North Sumatra ◽  
Poverty Levels ◽  
Positive Effect

The research aims to examine and analyze effects of economic growth, human development index (HDI), population, unemployment, and investment on poverty levels in the North Sumatra Province. The research uses quantitative data type, while the data source is obtained from secondary data in the quarterly form of 2010-2019. The data are analyzed with the model of Autoregressive Distributed Lag (ARDL) analysis. The results of ARDL analysis of economic growth variables and HDI have negative and significant effects on poverty levels in the short term and long term. Unemployment variable has a significant positive effect on poverty levels in the short term however insignificant in the long term and investment variable has an insignificant positive effect on the poverty level in the short and long term. Keywords: Economic Growth, HDI, Population, Unemployment, Investment, Poverty.

scholarly journals Deformation along an apparent seismic barrier: a palaeoseismological study along the North Anatolian Fault

1996 ◽  
Vol 39 (3) ◽  
Author(s):  
G. W. Michel ◽  
C. Janssen
Keyword(s):  
Strike Slip ◽  
North Anatolian Fault ◽  
Deformation Mechanisms ◽  
Normal Faulting ◽  
Short Term ◽  
The North ◽  
Spatial Changes ◽  
Major Fault ◽  
Event Triggered

An overstep in the North Anatolian Fault, possibly acting as a seismic barrier, was investigated for its structural and palaeoseismological characteristics. Study interests were: i) to find overstep related spatial changes in deformation which would help assess the structure as a long term singularity in the fault; ii) to identify short term, event-triggered changes in structures where the major fault enters the overstep i.e., in an area where seismogenic slip is impeded or even arrested; iii) to investigate whether or not the surface overstep is related to a seismic barrier, and iv) to discuss structures that might possibly be characteristic of barriers. In order to achieve this: a) largescale faults were mapped in the area, b) fault-slip data were measured in 56 outcrops along and within the overstep, and c) trenches were dug at the eastern rim of the overstep where recent earthquake structures had been reported. Derived long term stretching directions and ratios change significantly over the fault step and structures of recent major earthquakes suggest different deformation mechanisms for different events at the same Location e.g. strike-slip, thrust and normal faulting.

scholarly journals Energetická vs. environmentálna bezpečnosť: Prípad ropovodu Bratislava–Schwechat

2014 ◽  
Vol 16 (4) ◽  
pp. 326-344
Author(s):  
Zuzana Lorenčíková ◽  
Matúš Mišík
Keyword(s):  
Energy Security ◽  
Research Question ◽  
Environmental Security ◽  
Short Term ◽  
Governmental Organization ◽  
Oil Pipeline ◽  
Pipeline Networks ◽  
Preparation Phase ◽  
Project Stress

The paper analyses the development of the Bratislava–Schwechat Pipeline, which is supposed to connect the Slovak and Austrian oil pipeline networks. The research question asks why the project is being developed without taking into account arguments concerning environmental security even though rather significant environmental opposition to the pipeline has arisen. While the proponents of the project stress mainly its importance for the fostering of Slovak energy security, its opponents claim that the pipeline will endanger the current level of environmental security, since it presents a risk to Slovak fresh water reservoirs. In line with the theoretical approach, the paper argues that the conflict between these two types of security is positively skewed towards energy security, because its proponents are able to support their argumentation with concrete evidence. Moreover, advantages from improvements in energy security are visible in the short-term. On the other hand, the possible future negative environmental impacts of the pipeline are not so easy to assess (or quantify) and are of a long-term nature. The analysis also shows that due to the lack of activity of the Slovak Ministry of the Environment, a non-governmental organization Nie ropovodu (No to the pipeline) has become the main proponent of environmental security through the preparation phase of the project.

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