Central Sector Research Articles

Locating wind farm for power and hydrogen production based on Geographic information system and multi-criteria decision making method: An application

Hydrogen generation from renewable energy resources is considered as a suitable solution to solve the problems related to the energy sector and the reduction of greenhouse gases. The aim of this study is to provide an integrated framework for identifying suitable areas for the construction of wind farms to produce hydrogen. For this purpose, a combined method of Geographic Information System (GIS) and multi-criteria decision making (MCDM) has been used to locate the power plant in Yazd province. The GIS method in the present study consisted of two parts: constraints and criteria. The constraint section included areas that were unsuitable for the construction of wind farms to produce power and hydrogen. In the present study, various aspects such as physical, economic and environmental had been considered as constraints. In the criteria section, eight different criteria from technical aspects (including average wind speed, hydrogen production potential, land slope) and economic aspects (including distance to electricity grid, distance to urban areas, distance to road, distance to railway and distance to centers of High hydrogen consumption) had been investigated. The MCDM tool had been used to weigh the criteria and identify suitable areas. Analytic Hierarchy Process (AHP) technique was used for weighting the criteria. The results of AHP weighting method showed that economic criteria had the highest importance with a value of 0.681. The most significant sub-criterion was the distance to urban areas and the least significant sub-criterion was the distance to power transmission lines. The results of GIS-MCDM analysis had shown that the most proper areas were in the southern and central sectors of Yazd province. In addition, the feasibility of hydrogen production from wind energy had shown that this province had the capacity to generate hydrogen at the rate of 53.6–128.6 tons per year.

Distribution, morphology and composition of mesophotic ‘reefs’ on the Amazon Continental Margin

The geomorphology of the Amazon Continental Margin (ACM) is highly heterogeneous and includes a variety of reef-like formations found in deep-water along the shelf-slope transition. The ACM has been divided into three Sectors (Northern, Central and Southern) according to the distribution of the carbonate producers and the ‘reefs’, influenced by the Amazon River plume. Here, we characterize these structures that were sampled with a manned submersible and multibeam surveys to depths of up to 230 m, exploring their relationship with the Amazon river plume and changing sea level following the Last Glacial Maximum (LGM). The shelf-slope transition and a deeper shelf break in the Northern Sector of the Brazilian portion of the ACM carry a series of prominent high-relief structures (HRS) that experience a strong fluvial influence. The tops of these features are between 110 and 165 m depths and seem to have originated during lowstands, through erosion of Pleistocene sandstones. Siliciclastic and carbonate deposits accumulated on the tops of these features in shallow waters during the LGM and early deglaciation and were gradually submerged by rising sea level and subsidence. A thin layer of encrusting organisms, coralline algae, sponges, bryozoans and serpulids presently colonizes most of these surfaces at the sites sampled and contributes to the aggregation of thin fine-grained siliciclastic deposits. The Central Sector, off the river mouth, is associated with long-term sediment accumulation and lacks a shelf break. Nevertheless, living benthic communities occur on rock outcrops. The Southern Sector is less influenced by the river plume and includes a shallower shelf-break and a prominent canyon. The surveyed outcrops of Pleistocene carbonate and siliciclastic rocks at 180 m carry thin covers of a benthic community dominated by sponges and coralline algae, which is responsible for the accumulation of a thin (up to a few centimeters) deposit of carbonate bioclasts, quartz sand and mud on the rocky substrate. Thus, the ‘reefs’ of the outer shelf and mesophotic Amazon margin are typically eroded older rocks, colonized by encrusting organisms during the LGM and deglaciation forming a carbonate veneer, which now support a mesophotic community.

A shared earth approach to siliciclastic reservoir characterization: The Zubair Fm of Northern Kuwait

An innovative, integrated characterization workflow is applied to complex siliciclastic reservoirs of the Lower Cretaceous Zubair Formation in the Bahrah Field of Northern Kuwait. A detailed sedimentological and petrophysical assessment, integrated with 3D seismic interpretation, constrained and delineated vertical and lateral facies changes within the field, which is also affected by complex fault and fracture patterns. Siliciclastic geo-bodies have been documented and mapped in 1D, 2D and 3D using seismic stratigraphy, seismic attributes and high-resolution seismic inversion reservoir characterization workflows. The spatial distribution of these geo-bodies appears to show the development of fluvio-deltaic systems in the southern and central sectors of the field, which evolved into marine dominated/tidally influenced deltaic systems towards the northern and eastern sectors. Two major fluvial channels trends have been identified: SW-NE and W-E, with a dominantly NE trending deltaic progradation. Towards the north, elongated (tidal mouth?) sand bars have been interpreted with a NW-SE trend. An integrated sequence stratigraphic framework was consequently developed to better assess the influence of relative sea level changes on sedimentary facies. This framework pointed to the influence of marine incursions and subsequent flooding surfaces, which lead to the development of shale-rich seals and/or baffles that could increase the probability of structural-stratigraphic trapping mechanisms in these depositional environments. This integrated workflow was utilized to update a numerical static reservoir model, which further de-risked future drilling locations and potentially charged reservoir volumes.

Analyzing the stock market performance of central public sector enterprises disinvested through public offering mode: Indian evidence

PurposeThe present study aims to examine the short-term effect of disinvestment oriented IPOs and FPOs on the stock market performance of Indian central public sector enterprises (CPSEs), which divested their equity between 2000 and 2017.Design/methodology/approachThe analysis of stock price reaction is conducted for listing dates only in the case of IPOs and three different dates in the case of FPOs through the event study methodology. The three-event dates related to FPOs are public notification date (PND), issue announcement date (IAD) and price band date (PBD).FindingsOverall empirical analysis indicates that investor sentiments are generally insignificant prior to and posts the PND (first date). The second major date of announcement that is (IAD) is new information in the market and returns are found to be significantly negative across both the periods that is before and after IAD. Thus, the analysis depicts strongly negative investor sentiments in the case of IAD. These results are further substantiated by negatively significant CAR (cumulative abnormal returns) values for both the pre and post-event windows of PBD as well.Research limitations/implicationsEmpirical analysis concludes that investors do not stand a chance to gain abnormal returns through initiating positions in the stocks of CPSEs during the alternative event dates analyzed.Originality/valueSince the year 2000, disinvestment through public offering has gathered momentum, and this mode accounts for approximately 62% of the collective disinvestment funds generated by the government of India till now. But there have been very limited research studies on the market performance of disinvested CPSEs. This analysis provides new empirical evidence for the market reactions of retail investors in response to the sale of equity by the Indian government in CPSEs.

Analisis Sinergi Pokdarwis Desa Gondosuli dan Perhutani dalam Pengelolaan Wisata Bukit Mongkrang Karanganyar Jawa Tengah

Indonesian tourism is a leading sector that can significantly increase revenue for the country and the region. The regional tourism development process is also based on the Regional Tourism Development Master Plan. This did not escape the interfering role of the local Pokdarwis in the development of the regional tourism sector. So far, there is still a lot of potential for the tourism sector in the area that is no less interesting than the central tourism sector, one of which is the Bukit Mongkrang Tourism Destination located in Gondosuli Village, Tawangmangu District, Karanganyar Regency, Central Java which is a tourist destination resulting from the synergy between Pokdarwis with Perhutani (BUMN). Pokdarwis plays an important role in the management of Mongkrang Hill tourism. The purpose of holding this research is to find out the synergies and profit-sharing cooperation systems carried out by Perhutani and Pokdarwis in the management of Mongkrang Hill Tourism. In addition, this study aims to describe what roles Pokdarwis plays in managing Mongkrang Hill tourism and the perceived impact and what factors support and hinder the development process of Mongkrang Hill Tourism Destinations. The author uses a descriptive research method with a qualitative approach in this study. With data collection techniques obtained from in-depth interviews and field observations as primary data sources, as well as related journals and other scientific articles used as secondary sources. Data analysis was obtained in the form of a clear picture of the object of research and conclusions were drawn. The results showed that the synergy between Perhutani and Pokdarwis went smoothly, supported by the role of Pokdarwis in object management and the utilization of Mongkrang Hill Tourism potential was quite good.

Central and territorial governmental institutions involved in health promotion for older people in European Union countries


 Defining, planning and achieving health goals including health promotion and health promotion for older people (HP4OP) are always the responsibility of the public authority. In European countries the public health and health promotion strategic framework, including HP4OP is provided by the ministry of health or others national public health organisations, which are responsible for defining of legal regulations on the different aspects of health promotion.
 The goal of this article is the analysis of the central and territorial government (CTG) sector’s involvement in the issue of HP4OP, their functions, activities and responsibilities in this area. The analysis is focused on the main differences and similarities between CTG’s institutions.
 The authors triangulated data collected using varied methods: literature review, questionnaire research (conducted in European Pro-Health 65+ project’s countries) and in-depth interviews with national experts from selected countries.
 In the majority of analysed countries, the central government and municipalities are the main stakeholders responsible for providing funding for these programs. The operational level for the implementation of majority HP4OP is the local level. Research countries have been identified as strongly varying in institutional, legal and political specificity. The analysis shows the increasing position of HP4OP in public health policy. Many of the identified problems come from the implementation of a fragmented approach, the duplication of efforts undertaken by different stakeholders and the lack of a co-ordinated strategy and dedicated legal regulations at both the national and regional/local levels.

Sedimentary dynamics and topographic controls on the tidal-dominated Zagra Strait, Early Tortonian, Betic Cordillera, Spain

Abstract The approximately 350 m-thick stratigraphic succession of the Zagra Strait records an important oceanographic phase of basin interconnection between the Atlantic Ocean (Guadalquivir Basin) and the Mediterranean Sea through the Betic Cordillera (southern Spain) during the early Tortonian. The Zagra Strait developed as a narrow structurally controlled marine corridor. The sedimentary dynamics of the Zagra Strait were interpreted from the sedimentological features observed in six sections at well-exposed outcrops. Large-scale (>10 m high) compound dunes and compound–dune complexes moved parallel to the strait margins under strong tidal currents generated by tidal amplification at the strait entrance and exit. Dune distribution can be divided into three sectors with different palaeocurrent migration, lithological and topographical characteristics. The northern and central sectors were separated by a deep depression (>75 m water depth) where tidal currents were weaker and dunes were not generated. The southern sector records a relative decrease in current strength compared with the northern and central sectors, and a significant increase in the bioclastic content in the sediment. Terrigenous content generally increases towards the strait margins, and reciprocally, carbonates towards its axis. The closure of the Zagra Strait resulted from tectonic uplift of that part of the Betic Cordillera before the late Tortonian.

Towards ecosystem service assessment: Developing biophysical indicators for forest ecosystem services

Forests are specifically relevant for biodiversity and provide a wide range of ecosystem services. However, Europe’s forests and their services are threatened. Temperate, boreal and Mediterranean forests are facing deforestation, fragmentation and conversion due to human impact and recent developments in climatic conditions.Currently, not all forest ecosystem services are comprehensively accounted for and often, primarily timber production is considered. The aim of the present article is to further develop forest ecosystem service assessment using a systematic approach to assess biophysical indicators for ecosystem services. In this way, we aim to promote the use of forest function mapping, which is an important planning tool in the Central European forest sector for mapping forest areas of particular relevance for protection and recreation. Building on forest function mapping and the Common International Classification of Ecosystem Services (CICES 5.1), we selected six ecosystem services and propose indicators for their biophysical quantification. The indicator selection process followed specific selection criteria.We propose indicators for the potential, supply, demand and flow of the following forest ecosystem services: (i) groundwater for drinking purposes, (ii) timber provision, and (iii) global climate regulation. For the ecosystem service (iv) local air pollution reduction, indicators for potential, demand and flow are proposed, for (v) recreation, as well as (vi) education and training, indicators for the ecosystem services’ supply, demand and flow are proposed. In addition, possible measuring methods and units, and necessary data sources for applying the indicators are provided.

The Volcano-Tectonics of the Northern Sector of Ischia Island Caldera (Southern Italy): Resurgence, Subsidence and Earthquakes

The island of Ischia, an active volcanic field emerging in the western sector of the Gulf of Naples (Southern Italy), represents an archetypal case of caldera that underwent a very large resurgence related to the intrusion of a shallow magma body. The resurgence culminated with the formation of a structural high in the central sector of the island, i.e., the Mt. Epomeo block. This is bordered by a system of faults along which volcanic activity occurred up to 1302 A.D., and damaging earthquakes were generated in historical and recent time. The seismicity is located prevalently in the northern sector of the island and appears to be correlated with the most recent phase (<5 ka) of ground movement (subsidence), although the mechanism of earthquakes’ generation is still debated. By jointly analyzing offshore and onshore data (seismic profile and stratigraphy wells, respectively) and new petrological and geochemical data related to the most recent phase of volcano-tectonic activity, we develop a geological and structural layout of the northern sector of the island. In particular, we identify the seismogenic fault associated with the historical and recent destructive earthquakes of Ischia. This fault formed in the northern sector of the island during the final stage of the resurgence. We also propose a conceptual volcano-tectonic model of the northern sector of the Ischia Island, depicting the displacement of the fault zones in the off-shore area and the possible mechanism of stress loading and release in the on-shore zone, which is mainly driven by the subsidence of the Mt. Epomeo block. Our results are crucial for evaluating the dynamics of the seismogenic structures in the framework of the general subsidence of the island, as well as the related seismic hazard.

RESEARCH ON THE MACRO NET FINANCIAL ASSETS VALUE EFFECT OF MONETARY POLICY

This paper focuses on the impact of Chinese and US monetary policy on the net financial assets value of macro balance sheet from both theoretical and empirical aspects and reveals the sectoral solvency risk conduction path based on the balance sheet channel. In addition, the paper is focused on the effects of the interest rate as a target tool for monetary policy on the macro net financial assets. In the theoretical analysis, the net present value model of the economy is constructed, and a general equilibrium model representing the relationship between the real interest rate and net asset value of five sectors is derived (government, financial, resident, enterprise and central bank sector). This model explains the basic principle how interest rates affect net financial assets values. The dataset includes the central bank, commercial banks and shadow banks, and the stock and equity liabilities of the debtor are taken as the net asset of financial institutions during the period 2000–2016. The empirical results show that an increase in the real deposit interest rate improves the net financial assets value of the four sectors, and an increase in the real loan interest rate reduces the net financial assets value of the four sectors, while the effect of the real loan interest rate is greater than the real deposit interest rate. The effect ranking of interest rates on the four sectors is financial, enterprise, government, and resident sector. Overall, loose monetary policies can reduce macro-financial risks through the balance sheet channel, while the negative effects of long-term low-interest policies should be prevented; the macro-policies should hedge sectoral risks triggered by the exit of the easing policy via the macro balance sheet channel.

Retinal and choroidal vascular changes in newly diagnosed celiac disease: An optical coherence tomography angiography study.

Purpose:To investigate the retinal and choroidal microcirculation changes in celiac disease (CD) patients via optical coherence tomography angiography (OCT-A).Methods:This cross-sectional study included 44 pediatric patients with newly diagnosed CD and 44 healthy pediatric subjects. The vascular densities (VD) of the superficial, deep, and choriocapillar plexuses (VDs, VDd, and VDcc, respectively) (%), the superficial and deep foveal avascular zones (FAZs and FAZd) (%), the central macular thickness (CMT) (mm), and the subfoveal choroidal thickness (SFCT) (mm) were measured with swept-source OCT-A in addition to a complete ophthalmological examination.Results:Mean ages of the CD patients and the healthy participants were 12.02 ± 2.9 and 13.6 ± 2.3 years, respectively. The central sectors of the VDs and VDd measurements were found to be significantly higher in the study group compared to the control group (p = 0.006; P = 0.001, respectively), and the temporal and nasal values of the VDcc measurements were significantly lower in the study group than in the control group (p < 0.05 for both values). CMT and FAZ metrics did not differ between the groups (p > 0.05). SFCT was significantly reduced (p = 0.001), and choroidal thinning was more considerable in female CD patients (p = 0.045).Conclusion:CD seems to affect macular and choroidal microcirculation. The reduced choriocapillaris plexus parameters and choroidal thickness may provide disease activity information.

Glacial geomorphology of the central and southern Chilotan Archipelago (42.2°S–43.5°S), northwestern Patagonia

ABSTRACT We present a geomorphic map of the glacial landforms associated with the Golfo Corcovado ice lobe in northwestern Patagonia. Built upon prior studies, our map elaborates on the central and southern sectors of Isla Grande de Chiloé and neighboring islands. Through a combination of remote sensing techniques and exhaustive fieldwork, we identified a suite of ice-marginal, subglacial, and glaciofluvial features created by the Golfo Corcovado ice lobe during four maxima within the last glacial cycle, in none of which the ice-front reached the Pacific coast of Isla Grande de Chiloé. Our mapping builds a foundation and provides insights for future interdisciplinary research on the Late Quaternary sequence of glacial and paleoclimatic events in this key sector of northwestern Patagonia.

Design and performance of the prototype Schwarzschild-Couder telescope camera

The prototype Schwarzschild-Couder Telescope (pSCT) is a candidate for a medium-sized telescope in the Cherenkov Telescope Array. The pSCT is based on a novel dual mirror optics design which reduces the plate scale and allows for the use of silicon photomultipliers as photodetectors. The prototype pSCT camera currently has only the central sector instrumented with 25 camera modules (1600 pixels), providing a 2.68$^{\circ}$ field of view (FoV). The camera electronics are based on custom TARGET (TeV array readout with GSa/s sampling and event trigger) application specific integrated circuits. Field programmable gate arrays sample incoming signals at a gigasample per second. A single backplane provides camera-wide triggers. An upgrade of the pSCT camera is in progress, which will fully populate the focal plane. This will increase the number of pixels to 11,328, the number of backplanes to 9, and the FoV to 8.04$^{\circ}$. Here we give a detailed description of the pSCT camera, including the basic concept, mechanical design, detectors, electronics, current status and first light.

Endemic Hemicryptophyte Grasslands of the High Mountains of the Caribbean

Although there are numerous studies on the floristic composition of the Andean and Caribbean grasslands, there are limited information from a phytosociological point of view. This work therefore aims to highlight the differences in this important vegetation type in these two biodiversity hotspots to gain a better understanding of their floristic and vegetational richness. The floristic composition of Andean grasslands (Ecuador) and the island of Hispaniola is also studied. The reason for this comparative analysis of Andean and Caribbean territories is their tropical character and their bioclimatic similarities. The comparative analysis of Peruvian Andean and Colombian grasslands is based on floristic knowledge from the literature, our inventories on the island of Hispaniola, and the works of Peguero. We applied the phytosociological methodology of Braun-Blanquet and the code of phytosociological nomenclature. We performed a statistical analysis to verify the differences between both community types using the statistical packages PAST© and CAP3. The comparative analysis of Andean and Caribbean grasslands shows a clear floristic and biogeographical differentiation and reveals that the only ecological character they share is their high-mountain attribute. In the Caribbean these communities are found only on the island of Hispaniola (Dominican Republic) in the Central biogeographic sector, Central subprovince, Hispaniola province. These grasslands are exclusive to Hispaniola and have a high rate of endemics. We propose the following new syntaxa: the association Hyperico constanzae-Danthonietum domingensis, the alliance Hieracio domingensis-Deschampsion domingensis, the order Danthonietalia domingensis, and the class Deschampsio-Danthonietea domingensis. We found high biodiversity values for Andean and Caribbean areas. This is due to the intense anthropic activity on the island of Hispaniola, which has led to a high percentage of naturalized plants.

SHARING KNOWLEDGE OF CREATIVITY OF SMALL AND MEDIUM BUSINESSES FACING THE CHALLENGES OF THE CONDITION OF COVID-19

The main objective of this study is to find out and resolve the issues of Small and Medium-Sized Enterprises (SMEs) in Indonesia, particularly those located in Central Java's industrial sector, the northern sub-section. Primary and secondary data are used, and thereby a combination of data analysis techniques is used. The SMEs criteria are based on the Republic of Indonesia's Law No. 20 of 2008 on Micro, Small, and Medium-Sized Enterprises. According to the study's findings, SME owners were able to thrive by repackaging products, redesigning packaging, and establishing new marketing relations. This study developed the concepts of the creative knowledge sharing model, which is a synthesis of two theories, namely knowledge sharing and social identity.&#x0D; &#x0D; Keywords: Knowledge Sharing, Creativity, Social Identity, SMEs.

Epidemiological indicators and correlations of adolescent aggression in an urban student population

Adolescent aggression has received a wide and longtime attention in scientific research, because of the extent of the phenomenon in this age group and of the negative consequences it inflicts on affected adolescents, and their human environments. The aim of this cross-sectional study was to determine the proportion (of high levels) of aggressive behaviors (physical, verbal, and direct aggression, anger, and hostility) in an urban sample of adolescent students, as well as to investigate associations between the occurrence of these behaviors, and adolescents' characteristics and mental health problems. The sample consisted of 2050 students attending the second grade of 49 random selected High Schools and Senior High Schools of the Regional Unit of the Central Sector of Attica and Piraeus. The Buss- Perry Aggression Questionnaire was administered to measure participants' aggression behaviors, while the Strength and Difficulties Questionnaire was also used to estimate their mental health and behavioral difficulties. Information about adolescents' individual, family, and school characteristics, was also collected. Results of the statistical analysis showed that the occurrence rates of high levels of participants' aggressive behaviors ranged between 2.2 (for total aggression) and 10.5% (for anger). Among individual characteristics, gender (with boys predominating in physical and direct aggression and girls in anger), (older) age, and sports activity (to direct aggression) were related to participants' aggressive behaviors. On the other hand, non-intact family structure and household insecurity food intake were positive correlated with specific aggressive behaviors, while pocket money allowance was positive associated with all of them. Concerning participants' mental health and behavioral issues, conduct problems and hyperactivity/ inattention were positive correlated with all investigated aggressive behaviors. In conclusion, the vast majority of the Central Sector of Attica and Piraeus adolescents did not seem to show high levels of aggressive behaviors (except anger). Nevertheless, considering this study outcomes (such as the "aggressive" burden of older adolescents, the role of family structure and pocket money allowance, as well as the co-occurrence with mental and behavioral problems), further longitudinal study is required to better understand the mechanisms that facilitate adolescent aggression.

Coastal evolution assessment and prediction using remotely sensed front vegetation line along the Nigerian Transgressive Mahin mud coast

Over the past decades, the Transgressive Mahin mud coastline has drastically receded due to the continuous impacts of waves and the intensifying frequency of floods. Consequently, changes in the coastline positions for the past 20 years were investigated using multispectral satellite images within the Geographic Information System environment. The study area was divided into three sectors, and the sectors were further divided into several transects at uniform intervals. Statistical Linear Regression Rate (LRR), Endpoint Rate (EPR) and Root Mean Square Error (RMSE) methods were used to assess the rates of changes in coastline positions. Also, future coastline positions for 2022 and 2029 were predicted and estimated. The study revealed that more land area was lost in the eastern sector than any other sector after about 95% of the coastline along the entire region eroded from 2015 to 2019. This confirms a shift of erosion dominance from the central sector, which has been the most vulnerable to coastal hazards over the past decades. In the same period, it was revealed from the transect rates that about 51% of the western sector’s coastline experienced accretion attributable to sand deposition from the adjacent Barrier-lagoon coast, though, approximately 65% of the coastline along the same sector had previously eroded from 1999 to 2015. Based on these findings, and without immediate response to the coastal challenges, about 3.6 km 2 and over 11.3 km 2 could be lost by 2022 and 2029, respectively. To develop a practical solution, recent changes and future projections would need to be factored in. Therefore, the relevance of this study cannot be overemphasised, as it (i) identified areas of erosion, (ii) predicted future changes of the coastline, (iii) aims to start a new trend of future projections to enhance decision making and (iv) proposed a management plan for the area.

Agreement of different OCT scan directions for individual retinal-layer thickness measurements in multiple sclerosis subjects with prior unilateral optic neuritis

The similarities between horizontal and vertical Optical Coherence Tomography (OCT) scans for the individual retinal layer thickness measurements in the macula was evaluated. Two volumetric scans (B-scans oriented horizontally and vertically) were performed in 64 multiple sclerosis subjects with history of unilateral optic neuritis and 64 healthy controls. The agreement between the thickness measurements with horizontal and vertical OCT scans was evaluated in 3 groups of eyes: healthy controls, eyes with history of optic neuritis and the fellow eyes. The mean difference in individual layer thickness between the scans was smaller than the instrument’s axial resolution in all 3 groups. The limit of agreement (LoA) varied among the different layers and sectors analyzed and this trend was similar in all the groups. For the inner retinal layers (retinal nerve fiber layer to inner nuclear layer), the inner macular sectors had a larger LoA compared to the corresponding outer sectors. In the outer plexiform and nuclear layers, the central and inner sectors (except inner temporal) had LoA larger than the other sectors and layers. The larger LoA seen for different layers and sectors suggests that the scan direction must be same for the follow-up OCT measurements and in clinical studies.

Integrated on‐land‐offshore stratigraphy of the Campi Flegrei caldera: New insights into the volcano‐tectonic evolution in the last 15 kyr

AbstractSilicic calderas are volcanic systems whose unrest evolution is more unpredictable than other volcano types because they often do not culminate in an eruption. Their complex structure strongly influences the post‐collapse volcano‐tectonic evolution, usually coupling volcanism and ground deformation. Among such volcanoes, the Campi Flegrei caldera (southern Italy) is one of the most studied. Significant long‐ and short‐term ground deformations characterise this restless volcano. Several studies performed on the marine‐continental succession exposed in the central sector of the Campi Flegrei caldera provided a reconstruction of ground deformation during the last 15 kyr. However, considering that over one‐third of the caldera is presently submerged beneath the Pozzuoli Gulf, a comprehensive stratigraphic on‐land‐offshore framework is still lacking. This study aims at reconstructing the offshore succession through analysis of high‐resolution single and multichannel reflection seismic profiles and correlates the resulting seismic stratigraphic framework with the stratigraphy reconstructed on‐land. Results provide new clues on the causative relations between the intra‐caldera marine and volcaniclastic sedimentation and the alternating phases of marine transgressions and regressions originated by the interplay between ground deformation and sea‐level rise. The volcano‐tectonic reconstruction, provided in this work, connects the major caldera floor movements to the large Plinian eruptions of Pomici Principali (12 ka) and Agnano Monte Spina (4.55 ka), with the onset of the first post‐caldera doming at ca. 10.5 ka. We emphasise that ground deformation is usually coupled with volcanic activity, which shows a self‐similar pattern, regardless of its scale. Thus, characterising the long‐term deformation history becomes of particular interest and relevance for hazard assessment and definition of future unrest scenarios.

Morpho-stratigraphic characterization of the southern shelf of Porto Santo Island (Madeira Archipelago): Insights for small-scale instability processes and post-LGM sedimentary architecture

Shelves surrounding volcanic islands represent only a small portion of the entire submarine edifice that can extend to a few thousand meters below sea level. Despite their small areas, shelves show a significant morphologic imprint made by the erosional, depositional, tectonic and volcanic processes when compared to those left on slopes or the submarine bases of islands. Therefore, shelf morphology can be used to improve our knowledge about the island evolution, especially the more recent events. In this study, we use multibeam bathymetry, side scan sonar and seismic reflection profiles of the southern shelf of Porto Santo Island in Madeira Archipelago to map its seabed morphology and seismic stratigraphy from the nearshore to the shelf edge. Based on morphological and seismo-stratigraphic differences, the study area has been divided in three sectors (Western, Central and Eastern). In general, the shelf consists of an erosive rocky surface mostly covered by sediments, and locally outcropping on the seafloor, especially on the Western and Eastern sectors. On these sectors two sets of submerged erosional terraces have been mapped at different depths (35–45 m, 50–75 m). The depth range of the terraces and their absence in the Central sector suggests that these were formed/modified at least by the Marine Isotope Stages (MIS) 5a-5d stillstands or even by older relative sea-level stillstands. Dykes, which are more resistant to erosion than the surrounding outcrops, have orientations that are similar to the volcanic and structural features present on the island (NNE-SSW and NW-SE). The sedimentary cover on the shelf is highly varied both in thickness and internal architecture, mainly due to different onshore sediment supply and available accommodation space. Two main seismic units have been recognized: the lower one (U1) is interpreted as a transgressive deposit, formed during the sea level rise after the Last Glacial Maximum (LGM); the upper one (U2) is interpreted as a modern highstand deposit. The Western sector is practically sediment-starved, except for a local thin sedimentary cover of U2 on the inner and outer shelf. The Central sector shows U2 as a sigmoidal-oblique progradational clinoform characterized by inner prograding geometry on top of U1. The Eastern sector shows U2 as sigmoidal clinoform extending over a large area and having a more aggradational component. The shelf edge shows an overall arcuate shape that strongly matches the coastline configuration, suggesting the occurrence of an old large-scale landslide event (LS1) prior to the shelf formation. Further incisions in the shelf edge of the Central sector are interpreted as resulting from mass-movements, classified as LS2 and LS3. LS2 is at least older than seismic unit U1 and LS3 formed during the late Holocene. The volume of the LS2 event (0.6 km3) suggests that it might have caused a hazardous tsunami if it failed as a single event. The recent LS3 events, due to their small magnitude were probably not hazardous. These observations provided a more comprehensive understanding of the recent evolution of Porto Santo insular shelf in terms of mass-movement processes and post-LGM sedimentary architecture.