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Sample records for marmara sea inferred

  1. Near-Surface Dispersion and Circulation in the Marmara Sea (MARMARA)

    DTIC Science & Technology

    2009-01-01

    Sea (MARMARA) Pierre-Marie Poulain Istituto Nazionale di Oceanografia e di Geofisica Sperimentale Borgo Grotta Gigante, 42/c 34010 Sgonico...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Istituto Nazionale di Oceanografia e di Geofisica Sperimentale,Borgo Grotta Gigante, 42/c,34010 Sgonico

  2. Development of a Tsunami Scenario Database for Marmara Sea

    NASA Astrophysics Data System (ADS)

    Ozer Sozdinler, Ceren; Necmioglu, Ocal; Meral Ozel, Nurcan

    2016-04-01

    Due to the very short travel times in Marmara Sea, a Tsunami Early Warning System (TEWS) has to be strongly coupled with the earthquake early warning system and should be supported with a pre-computed tsunami scenario database to be queried in near real-time based on the initial earthquake parameters. To address this problem, 30 different composite earthquake scenarios with maximum credible Mw values based on 32 fault segments have been identified to produce a detailed scenario database for all possible earthquakes in the Marmara Sea with a tsunamigenic potential. The bathy/topo data of Marmara Sea was prepared using GEBCO and ASTER data, bathymetric measurements along Bosphorus, Istanbul and Dardanelle, Canakkale and the coastline digitized from satellite images. The coarser domain in 90m-grid size was divided into 11 sub-regions having 30m-grid size in order to increase the data resolution and precision of the calculation results. The analyses were performed in nested domains with numerical model NAMIDANCE using non-linear shallow water equations. In order to cover all the residential areas, industrial facilities and touristic locations, more than 1000 numerical gauge points were selected along the coasts of Marmara Sea, which are located at water depth of 5 to 10m in finer domain. The distributions of tsunami hydrodynamic parameters were investigated together with the change of water surface elevations, current velocities, momentum fluxes and other important parameters at the gauge points. This work is funded by the project MARsite - New Directions in Seismic Hazard assessment through Focused Earth Observation in the Marmara Supersite (FP7-ENV.2012 6.4-2, Grant 308417 - see NH2.3/GMPV7.4/SM7.7) and supported by SATREPS-MarDim Project (Earthquake and Tsunami Disaster Mitigation in the Marmara Region and Disaster Education in Turkey) and JICA (Japan International Cooperation Agency). The authors would like to acknowledge Ms. Basak Firat for her assistance in

  3. Fate of the Black Sea Acartia clausi and Acartia tonsa (Copepoda) penetrating into the Marmara Sea through the Bosphorus

    NASA Astrophysics Data System (ADS)

    Hubareva, Elena; Svetlichny, Leonid; Kideys, Ahmet; Isinibilir, Melek

    2008-01-01

    In October 2005 spatial distribution of live and dead Acartia clausi and Acartia tonsa was studied in the Black and Marmara Seas and near the Marmara Sea inlet of the Bosphorus, in order to understand their fate upon transportation between two seas. The morphometric characteristics in both species from all studied areas, and the decreased abundance of A. clausi and A. tonsa from the Black Sea towards the Marmara Sea indicate that the Marmara Sea Acartia populations are formed by recruitment from the Black Sea. We observed mass mortality of A. clausi in the Marmara Sea near the Prince Islands. The majority of carcasses (66% of total A. clausi numbers in the Marmara Sea) were found in the salinity gradient layer. Laboratory experiments showed that during a gradual salinity increase (3.5-4 h) from 18.9 (salinity of the Marmara Sea surface layers) to 39.8 (Marmara Sea salinity at depths >25 m) Acartia clausi began to die at a salinity of 30 and that all copepods were dead at 39.8. In comparison with A. clausi, Acartia tonsa was more tolerant to short-term salinity increase. Despite the high salinity tolerance of A. tonsa however, the abundance of this species was estimated to be very low in the offshore Marmara Sea. Respiration rate and frequency of jumps in A. tonsa were 1.3-1.5 and 1.77 times higher, respectively, than those in A. clausi.

  4. Offshore Seismic Observation in the Western Marmara Sea, Turkey

    NASA Astrophysics Data System (ADS)

    Yamamoto, Y.; Takahashi, N.; Citak, S.; Kalafat, D.; Pinar, A.; Gurbuz, C.; Kaneda, Y.

    2014-12-01

    The North Anatolian Fault (NAF) extends 1600 km westward from a junction with the East Anatolian Fault at the Karliova Triple Junction in eastern Turkey, across northern Turkey and into the Aegean Sea, accommodating about 25 mm/yr of right-lateral motion between Anatolia and the Eurasian plate. Since 1939, devastating earthquakes with magnitude greater than seven ruptured NAF westward, starting from 1939 Erzincan at the eastern Turkey and including the latest 1999 Izmit-Golcuk and the Duzce earthquakes in the Marmara region. Considering the fault segments ruptured by the May 24th, 2014 Northern Aegean earthquake, the only un-ruptured segments left behind NAF locate beneath the Marmara Sea and those segments keep their mystery due to their underwater location. To clarify the detailed fault geometry beneath the western Marmara Sea, we started to operate a series of ocean bottom seismographic (OBS) observations. As a first step, we deployed 3 pop-up type OBSs on 20th of March 2014 as a trial observation, and recovered them on 18thof June 2014. Although one of the OBSs worked only 6 days from the start of the observation, other two OBSs functioned properly during the whole 3-month observation period. Only 8 earthquakes were reported near the OBS network in 3 months periods according to the Kandilli Observatory and Earthquake Research Institute catalogue. Thus, we first searched for the microearthquakes missing by the land seismic network and estimated their precious location by using the initial 6 days data. We could identify about 50 earthquakes with more than 5 picking data of P and S first arrivals, and half of them located near the NAF. We also tested the hypocenter relocation by combining the land and OBS seismic data for the 8 earthquakes, and found that these earthquakes are located in between 12-24 km depths. Next, we are planning to deploy 10 OBSs from September 2014 to June 2015 as a second step for our observation. At the AGU fall meeting, we will be able to

  5. Mixed Layer Depth in the Aegean, Marmara, Black and Azov Seas: Part I: General Features

    DTIC Science & Technology

    2009-02-28

    r.com/ locate / jmarsysMixed layer depth in the Aegean, Marmara, Black and Azov Seas : Part I: General features A. Birol Kara a,⁎, Robert W. Helber a...suffer from lack of input T and S profiles in the Marmara and Azov Seas , thus they may not be representative.MonthlyMLDfields presented in this paper are...Boyer), .V.there has been no study which describes seasonal characteristics of MLD in the Aegean, Marmara, Black and Azov Seas , whose bottom

  6. Elongation Of The North Anatolian Fault Zone in the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Kurtulus, C.; Canbay, M. M.

    2003-04-01

    The North Anatolian Fault Zone (NAFZ) is a 1500 km long, seismically active, right lateral strike sleep fault that accommodates the relative motion between the Anatolian and Pontide blocks. The Sea of Marmara is an intra-continental sea lying along the western part of the NAFZ. There are two major fault systems in the Sea of Marmara one of which consists of the east-west striking faults and the other one is made up of NE-SW-trending faults that dissect the first group. The east, middle and the south parts of the Sea of Marmara are interpreted as pull-apart basins characterized by shear stresses. The interpretation of the structural framework indicates that the northern strand of the NAFZ traverses the Gulf of Izmit and deep Marmara to bind the Gulf of Saros and the middle strand of it traverses the Gulf of Gemlik, Bandirma and the Gulf of Erdek.

  7. The alien ascidian Styela clava now invading the Sea of Marmara (Tunicata: Ascidiacea).

    PubMed

    Çinar, Melih Ertan

    2016-01-01

    During the implementation of a large project aimed to investigate the benthic community structures of the Sea of Marmara, specimens of the invasive ascidian species Styela clava were collected on natural substrata (rocks) at 10 m depth at one locality (Karamürsel) in İzmit Bay. The specimens were mature, containing gametes, indicating that the species had become established in the area. The Sea of Marmara seems to provide suitable conditions for this species to survive and form proliferating populations.

  8. Near-Surface Dispersion and Circulation in the Marmara Sea (MARMARA)

    DTIC Science & Technology

    2010-01-01

    MARMARA) Pierre-Marie Poulain Istituto Nazionale di Oceanografia e di Geofisica Sperimentale Borgo Grotta Gigante, 42/c 34010 Sgonico...S) AND ADDRESS(ES) Istituto Nazionale di Oceanografia e di Geofisica Sperimentale,Borgo Grotta Gigante, 42/c,34010 Sgonico (Trieste), Italy, 8

  9. Morphometric analysis of the Marmara Sea river basins, Turkey

    NASA Astrophysics Data System (ADS)

    Elbaşı, Emre; Ozdemir, Hasan

    2014-05-01

    The drainage basin, the fundamental unit of the fluvial landscape, has been focus of research aimed at understanding the geometric characteristics of the master channel and its tributary network. This geometry is referred to as the basin morphometry and is nicely reviewed by Abrahams (1984). A great amount of research has focused on geometric characteristic of drainage basins, including the topology of the stream networks, and quantitative description of drainage texture, pattern, shape, and relief characteristics. Evaluation of morphometric parameters necessitates the analysis of various drainage parameters such as ordering of the various streams, measurement of basin area and perimeter, length of drainage channels, drainage density (Dd), stream frequency (Fs), bifurcation ratio (Rb), texture ratio (T), basin relief (Bh), Ruggedness number (Rn), time of concentration (Tc), hypsometric curve and integral (Hc and Hi) (Horton, 1932, Schumn, 1956, Strahler, 1957; Verstappen 1983; Keller and Pinter, 2002; Ozdemir and Bird, 2009). These morphometric parameters have generally been used to predict flood peaks, to assess sediment yield, and to estimate erosion rates in the basins. River basins of the Marmara Sea, has an area of approximately 40,000 sqkm, are the most important basins in Turkey based on their dense populations, industry and transportation systems. The primary aim of this study is to determine and analyse of morphometric characteristics of the Marmara Sea river basins using 10 m resolution Digital Elevation Model (DEM) and to evaluate of the results. For these purposes, digital 10 m contour maps scaled 1:25000 and geological maps scaled 1:100000 were used as the main data sources in the study. 10 m resolution DEM data were created using the contour maps and then drainage networks and their watersheds were extracted using D8 pour point model. Finally, linear, areal and relief morphometries were applied to the river basins using Geographic Information Systems

  10. Comparative metagenomics of bathypelagic plankton and bottom sediment from the Sea of Marmara

    PubMed Central

    Quaiser, Achim; Zivanovic, Yvan; Moreira, David; López-García, Purificación

    2011-01-01

    To extend comparative metagenomic analyses of the deep-sea, we produced metagenomic data by direct 454 pyrosequencing from bathypelagic plankton (1000 m depth) and bottom sediment of the Sea of Marmara, the gateway between the Eastern Mediterranean and the Black Seas. Data from small subunit ribosomal RNA (SSU rRNA) gene libraries and direct pyrosequencing of the same samples indicated that Gamma- and Alpha-proteobacteria, followed by Bacteroidetes, dominated the bacterial fraction in Marmara deep-sea plankton, whereas Planctomycetes, Delta- and Gamma-proteobacteria were the most abundant groups in high bacterial-diversity sediment. Group I Crenarchaeota/Thaumarchaeota dominated the archaeal plankton fraction, although group II and III Euryarchaeota were also present. Eukaryotes were highly diverse in SSU rRNA gene libraries, with group I (Duboscquellida) and II (Syndiniales) alveolates and Radiozoa dominating plankton, and Opisthokonta and Alveolates, sediment. However, eukaryotic sequences were scarce in pyrosequence data. Archaeal amo genes were abundant in plankton, suggesting that Marmara planktonic Thaumarchaeota are ammonia oxidizers. Genes involved in sulfate reduction, carbon monoxide oxidation, anammox and sulfatases were over-represented in sediment. Genome recruitment analyses showed that Alteromonas macleodii ‘surface ecotype', Pelagibacter ubique and Nitrosopumilus maritimus were highly represented in 1000 m-deep plankton. A comparative analysis of Marmara metagenomes with ALOHA deep-sea and surface plankton, whale carcasses, Peru subsurface sediment and soil metagenomes clustered deep-sea Marmara plankton with deep-ALOHA plankton and whale carcasses, likely because of the suboxic conditions in the deep Marmara water column. The Marmara sediment clustered with the soil metagenome, highlighting the common ecological role of both types of microbial communities in the degradation of organic matter and the completion of biogeochemical cycles. PMID

  11. Comparative metagenomics of bathypelagic plankton and bottom sediment from the Sea of Marmara.

    PubMed

    Quaiser, Achim; Zivanovic, Yvan; Moreira, David; López-García, Purificación

    2011-02-01

    To extend comparative metagenomic analyses of the deep-sea, we produced metagenomic data by direct 454 pyrosequencing from bathypelagic plankton (1000  m depth) and bottom sediment of the Sea of Marmara, the gateway between the Eastern Mediterranean and the Black Seas. Data from small subunit ribosomal RNA (SSU rRNA) gene libraries and direct pyrosequencing of the same samples indicated that Gamma- and Alpha-proteobacteria, followed by Bacteroidetes, dominated the bacterial fraction in Marmara deep-sea plankton, whereas Planctomycetes, Delta- and Gamma-proteobacteria were the most abundant groups in high bacterial-diversity sediment. Group I Crenarchaeota/Thaumarchaeota dominated the archaeal plankton fraction, although group II and III Euryarchaeota were also present. Eukaryotes were highly diverse in SSU rRNA gene libraries, with group I (Duboscquellida) and II (Syndiniales) alveolates and Radiozoa dominating plankton, and Opisthokonta and Alveolates, sediment. However, eukaryotic sequences were scarce in pyrosequence data. Archaeal amo genes were abundant in plankton, suggesting that Marmara planktonic Thaumarchaeota are ammonia oxidizers. Genes involved in sulfate reduction, carbon monoxide oxidation, anammox and sulfatases were over-represented in sediment. Genome recruitment analyses showed that Alteromonas macleodii 'surface ecotype', Pelagibacter ubique and Nitrosopumilus maritimus were highly represented in 1000  m-deep plankton. A comparative analysis of Marmara metagenomes with ALOHA deep-sea and surface plankton, whale carcasses, Peru subsurface sediment and soil metagenomes clustered deep-sea Marmara plankton with deep-ALOHA plankton and whale carcasses, likely because of the suboxic conditions in the deep Marmara water column. The Marmara sediment clustered with the soil metagenome, highlighting the common ecological role of both types of microbial communities in the degradation of organic matter and the completion of biogeochemical cycles.

  12. HYPODD Relocations and Stress Tensor Inversion Analyses of Local Earthquake Clusters in the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Korkusuz Öztürk, Yasemin; Meral Özel, Nurcan

    2016-04-01

    Extensional focal mechanism solutions are mostly observed even in the Central Marmara by this comprehensive research although the main Marmara Fault that is the western branch of the NAF, is dominated by a right lateral strike-slip regime. Marmara Region, a seismically very active area, is located at the western section of the North Anatolian Fault Zone (NAFZ). The 1912 Mürefte and 1999 Izmit earthquakes are the last devastating events of the western and eastern sections of this region, respectively. The region between the locations of these earthquakes, is prone to a large earthquake. Therefore, the analysis of the Sea of Marmara is significant. The main objective of this research is to determine earthquake hypocenters and focal mechanism solutions accurately, hence we obtain recent states of stresses for this region. Accordingly, this research aims to define branches of fault structures and its geometrical orientations in the Sea of Marmara. In this study, a cluster of events in the Central Marmara is analyzed using hypocenter program as a usual location technique. In addition, these events and other clustered events (Korkusuz Öztürk et al., 2015) are relocated using HYPODD relocation procedure. Even though NAF is mostly dominated by a right lateral strike slip fault, we found out many extensional source mechanisms. Also, from the comparison of relocation results of hypocenter and HYPODD programs, it is found out that most of the relocations have the same orientations and dipping angles of the segments of the main Marmara Fault are not clear. As a result, since we observe many normal faulting mechanisms in the Sea of Marmara, we expect to observe some deviations in orientations of vertical orientations of the fault segments comparing a dip-slip model. Therefore, this research will continue to clearly identify fault dip angles of main fault segments in Marmara Sea. Further, our sensitive relocation and stress analyses will make an important contribution to a

  13. Offshore seismicity in the western Marmara Sea, Turkey, revealed by ocean bottom observation

    NASA Astrophysics Data System (ADS)

    Yamamoto, Yojiro; Takahashi, Narumi; Citak, Seckin; Kalafat, Doğan; Pinar, Ali; Gurbuz, Cemil; Kaneda, Yoshiyuki

    2015-09-01

    The faults' geometry and their seismic activity beneath the Marmara Sea have been under debate for a couple of decades. We used data recorded by three ocean bottom seismographs (OBSs) over a period of 3 months in 2014 to investigate the relationship of fault geometry to microseismicity under the western Marmara Sea in Turkey. We detected a seismic swarm at 13 to 20 km depth beneath the main Marmara fault (MMF), and the maximum depth of seismogenic zone was 25 km within the OBS observation area. These results provided evidence that the dip of the MMF is almost vertical and that the seismogenic zone in this region extends into the lower crust. Our analysis of past seismicity indicated that the seismic swarm we recorded is the most recent of an episodic series of seismic activity with an average recurrence interval of 2-3 years. The repetitive seismicity indicates that the MMF beneath the western Marmara Sea is coupled and that some of the accumulated strain is released every 2 to 3 years. Our study shows that OBS data can provide useful information about seismicity along the MMF, but more extensive studies using more OBSs deployed over a wider area are needed to fully understand the fault geometry and stick-slip behavior of faults under the Marmara Sea.

  14. Mixed Layer Depth in the Aegean, Marmara, Black and Azov Seas: Part II: Relation to the Sonic Layer Depth

    DTIC Science & Technology

    2009-03-03

    r.com/ locate / jmarsysMixed layer depth in the Aegean, Marmara, Black and Azov Seas : Part II: Relation to the sonic layer depth Robert W. Helber a...index terms: The Aegean Sea The Black Sea The Azov Sea Keywords: Sound transmission Mixed layer depth Climatologyt analysis of the seasonal evolution of...the sonic layer depth (SLD) relative to the mixed layer depth (MLD) for the Aegean, Marmara, Black, and Azov Seas . SLD identifies the acoustic ducting

  15. The alien ascidian Styela clava now invading the Sea of Marmara (Tunicata: Ascidiacea)

    PubMed Central

    Çinar, Melih Ertan

    2016-01-01

    Abstract During the implementation of a large project aimed to investigate the benthic community structures of the Sea of Marmara, specimens of the invasive ascidian species Styela clava were collected on natural substrata (rocks) at 10 m depth at one locality (Karamürsel) in İzmit Bay. The specimens were mature, containing gametes, indicating that the species had become established in the area. The Sea of Marmara seems to provide suitable conditions for this species to survive and form proliferating populations. PMID:27047235

  16. Conceptual Design and Challenges for a Tsunami Early Warning System in the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Necmioglu, Ocal

    2015-04-01

    In this study, while discussing associated challenges such as contradictions between earthquake and tsunami mitigation activities in the Marmara Region, I suggest a conceptual design for a tsunami warning system in the Sea of Marmara upon an improved version of an applicable model for the near-field tsunami early warning and emergency planning in the Mediterranean Area presented by Papadopoulos and Fokaefs (2013). Due to the extreme short arrival times as a result of the close proximity of main fault lines to the coastal regions, and existence of potential submarine landslide sources, any tsunami early warning system in the Sea of Marmara has to be strongly coupled with the earthquake warning system and stakeholders of the tsunami mitigation activities, such as local and regional components of disaster and emergency management and civil protection units. Since 1900, around 90,000 people have lost their lives in 76 earthquakes in Turkey, with a total affected population of around 7 million and direct losses of around 25 billion USD (Erdik, 2013). Based on a time-dependent model that includes coseismic and postseismic effects of the 1999 Izmit earthquake with Mw = 7.4, the probability of an earthquake with Mw > 7 in the Sea of Marmara near Istanbul, as a mega-financial-city in the heart of the Marmara Region with a population around 13 million and 1,000,000 buildings, is 35% to 70% in the next 30 years (Parsons, 2004). Historical records indicate around 30 tsunamis in the Sea of Marmara until today (Altinok et al., 2011). Among those, catastrophic earthquakes such as 1509, 1766 and 1894 resulted in considerable tsunamis and some damage. Latest tsunami observed in Marmara was due to a triggered submarine landslide of 1999 Izmit earthquake which led to reported run-up heights of 1-3 m in most places (Tinti et al., 2006). Hence, the add-on impact of a tsunami generated by the anticipated next earthquake in the Sea of Marmara should not be neglected.

  17. Moho depth and crustal thinning in the Marmara Sea region from gravity data inversion

    NASA Astrophysics Data System (ADS)

    Kende, Julia; Henry, Pierre; Bayrakci, Gaye; Özeren, Sinan; Grall, Céline

    2016-04-01

    With a width comparable to the brittle crust thickness, the Sea of Marmara strike-slip basin appears as an intermediate case between two much studied end-member cases of basin-width-to-brittle-crust-thickness ratio: the Dead Sea and the Death Valley. But geophysical studies have shown evidences of at least 5 km of mantle uplift under the Marmara Sea, much larger than in the two other cases. We compiled data from reflection, refraction and tomography seismic studies to correct satellite and survey vessel gravity data (acquired during MARSITE cruise of Ifremer R/V Pourquoi Pas ?) from the effect of topography and sedimentary basins. Assuming that no other crustal mass heterogeneity affects the gravity measurement, we inverted the residual, with constraints from seismic studies, to calculate the topography of the Moho. The 3D model obtained shows a mantle uplift broadly correlated with the Marmara deep basins, but the crustal thinning spreads southward further than the basin limits, This is explained by ductile flow in the lower crust between a northern zone where the thinning is closely related to the Marmara Fault strike-slip basins and a southern zone where extension appears associated with older crustal detachment systems. Finally, we estimated the extension budget in the area during the Marmara Sea formation by comparing our 3D crust volume with an initial crust of constant thickness. The increase in surface area, 2100±300 km2, is compatible with present day GPS velocity field measurement assuming steady state and an initiation of extension in the area about 5 Myr ago. We conclude that although the zone went through tectonic reorganizations during the Pliocene as the North Anatolian Fault system propagated westward, the overall extension rate in the area could have been stable, or decreasing with time, and thus should be understood in a broader geodynamic framework comprising the Aegean subduction.

  18. Spatial and temporal changes in microbial diversity of the Marmara Sea sediments.

    PubMed

    Kolukirik, M; Ince, O; Cetecioglu, Z; Celikkol, S; Ince, B K

    2011-11-01

    Spatial (10 different locations) and temporal (2 years) changes in characteristics of the Marmara Sea Sediments were monitored to determine interactions between the chemical and microbial diversity. The sediments were rich in terms of hydrocarbon, nitrate, Ni and microbial cell content. Denitrifying, sulfate reducing, fermentative and methanogenic organisms were co-abundant in 15 cm below the sea floor. The local variations in the sediments' characteristics were more distinctive than the temporal ones. The sulfate and nitrate contents were the main drivers of the changes in the microbial community compositions. N and P were limited for microbial growth in the sediments, and their levels determined the total cell abundance and activity. Seasonal shifts in temperatures of the shallow sediments were also reflected in the active cell abundances. It was concluded that the Marmara Sea is a promising ecosystem for the further investigation of the ecologically important microbial processes.

  19. Active geodynamics of the Marmara Sea region: How to combine all geophysical observations?

    NASA Astrophysics Data System (ADS)

    Karabulut, Hayrullah; Schmittbuhl, Jean; Lengliné, Olivier; Bouchon, Michel

    2016-04-01

    The Marmara Sea region is presently hosting a major seismic gap along the North Anatolian Fault (NAF). The region is located at the western termination of a unique sequence of large earthquakes initiated by the 1939 Mw 7.9 Erzincan earthquake and propagated westwards over 1000 km. Understanding the active geodynamics of the Marmara region is essential to assess the seismic behaviour of the Main Marmara Fault (MMF) and its related structures. We therefore have taken an initiative to give a comprehensive view of the regional lithosphere and the geomechanical response of the fault trying to combine all important geophysical observations. Using the broadband seismic data acquired between 2007-2015, we computed crustal seismic velocity distribution (from ambient noise tomography), crustal thickness map (from receiver function analysis) and uppermost mantle velocity distribution (from Pn tomography). The vast amount of data provides a good spatial coverage of the region and high resolution of images. Along the Main Marmara Fault (MMF), we present the seismicity below the Marmara Sea for the period the 2006-2015 to provide insights on the seismic response of the fault. The analysis shows that the seismic behaviour is varying along the fault. In addition, long term repeating earthquakes are searched along the MMF and found in the western part of the MMF. In the light of accurate and extensive observations, several open questions emerge from this compilation: Is the cumulated seismic moment released by the repeaters comparable to tectonic rate of the fault in the region? Are there any correlations between the rheology of the crust and the seismic response of the fault? Is there an influence of the fault asymmetry on the fault rupture?

  20. The First Observation of Domoic Acid in Plankton Net Samples from the Sea of Marmara, Turkey.

    PubMed

    Dursun, Fuat; Yurdun, Türkan; Ünlü, Selma

    2016-01-01

    This study reports the first evidence of domoic acid (DA), an algal neurotoxin produced by the genus Pseudo-nitzschia, from plankton net samples collected in the Sea of Marmara in December, 2010 and February, 2011. DA concentrations of plankton net samples were analyzed by high-performance liquid chromatography (HPLC), using the fluorenylmethoxycarbonyl fluorescence derivatization technique (detection limit 0.2 ng DA). The biotoxin concentrations in samples from coastal waters varied between 0.96 and 5.25 µg DA/mL. We also investigated possible correlations between physicochemical parameters and DA concentration. The DA levels appear to be correlated negatively with silica and nitrite concentrations for both sampling periods. These data may be used to evaluate the probability of finding similar conditions in coastal waters of the Sea of Marmara in order to determine the potential risks to local aquaculture and fisheries.

  1. Long term seismic observation using ocean bottom seismographs in Marmara Sea, Turkey

    NASA Astrophysics Data System (ADS)

    Takahashi, N.; Pinar, A.; Kalafat, D.; Yamamoto, Y.; Citak, S.; Comoglu, M.; Çok, Ö.; Ogutcu, Z.; Suvarikli, M.; Tunc, S.; Gurbuz, C.; Ozel, N.; Kaneda, Y.

    2015-12-01

    The North Anatolian Fault crosses the Marmara Sea with a direction of E-W. There are many large earthquakes repeatedly along the fault with a linkage each other. Due to recent large eastern Aegean earthquake with M6, the Marmara Sea is the "blank zone". Japan and Turkey have a SATREPS collaborative study to clarify the structural characters, construct fault models, simulate the strong motion and tsunami, evaluate these risks with hazard maps and educate disaster prevention for local governments and residents. Our activity is one of the most basic studies, and the objectives are to clarify hypocenter locations, monitor the move, and construct fault models referring seismic/magnetotelluric structures, geodetic nature and trenching works. The target area is from western Marmara Sea to the off Istanbul area along the north Anatolian Fault. We deployed ten Ocean Bottom Seismographs (OBSs) between the Tekirdag Basin and the Central Basin in September, 2014. Then, we added five Japanese OBSs and deployed them at the western end of the Marmara Sea and the eastern Central Basin to extend observed area in March, 2015. The OBS has a three-component velocity sensor with a natural frequency of 4.5 Hz and a hydrophone. Japanese team have clarified seismicity around Japan using the OBS. The magnitude of the detected events is 1.0-1.5. We retrieved all 15 OBSs in July, 2015 and deployed them again on the same locations after data copy and battery maintenance. We started OBS data analysis combined with land stations data. Now we detect events automatically using these data and succeeded detection of over one thousand around the north Anatolian Fault. The tentative results show heterogeneous seismicity. The western and central basins have relative high seismicity and the seismogenic zone becomes thicker rather than previous estimation. Then we will evaluate hypocenter locations with high resolution and discuss the shape of faults in each segment and their linkage.

  2. Design and challenges for a tsunami early warning system in the Marmara Sea

    NASA Astrophysics Data System (ADS)

    Necmioğlu, Öcal

    2016-01-01

    Since 1900, around 90,000 people have lost their lives in 76 earthquakes in Turkey, with a total affected population of around 7 million and direct losses of around 25 billion USD. Based on a time-dependent model that includes coseismic and post-seismic effects of the 1999 Kocaeli earthquake with moment magnitude Mw = 7.4, Parsons (J Geophys Res. 109, 2004) concluded that the probability of an earthquake with Mw > 7 in the Sea of Marmara near Istanbul is 35 to 70 % in the next 30 years. According to a 2011 study, an earthquake with Mw = 7.25 on the Main Marmara Fault is expected to heavily damage or destroy 2 to 4 % of around 1,000,000 buildings in Istanbul with a population around 13 million, with 9 to 15 % of the buildings receiving medium damage and 20 to 34 % of the buildings damaged lightly (Erdik, Science 341:72, 2013). In the absence of adequate post-earthquake assembly areas especially in the heavily urbanized Istanbul, it is evident that after a major earthquake, especially in the coastal parts of the city, citizens would be storming to landfill assembly and recreational areas. Besides earthquakes, around 30 tsunamis have been reported by Altınok et al. (Natural Hazards Earth System Science 11:273-293, 2011) in the Marmara Sea. Among those, catastrophic earthquakes such as 1509, 1766, and 1894 resulted in considerable tsunamis and some damage. The latest tsunami observed in Marmara was due to a triggered submarine landslide of the 1999 Mw = 7.4 Kocaeli earthquake which led to reported run-up heights of 1-3 m in most places (Tinti et al., Marine Geology 225:311-330, 2006). In this study, I propose a design for a tsunami warning system specific for the Marmara region that is strongly coupled with the earthquake early warning system (due to the short arrival times of tsunami) and stakeholders of the tsunami mitigation activities, such as local and regional components of disaster and emergency management and civil protection units, to ensure that the citizens

  3. Possible worst-case tsunami scenarios around the Marmara Sea from combined earthquake and landslide sources

    NASA Astrophysics Data System (ADS)

    Latcharote, Panon; Suppasri, Anawat; Imamura, Fumihiko; Aytore, Betul; Yalciner, Ahmet Cevdet

    2016-12-01

    This study evaluates tsunami hazards in the Marmara Sea from possible worst-case tsunami scenarios that are from submarine earthquakes and landslides. In terms of fault-generated tsunamis, seismic ruptures can propagate along the North Anatolian Fault (NAF), which has produced historical tsunamis in the Marmara Sea. Based on the past studies, which consider fault-generated tsunamis and landslide-generated tsunamis individually, future scenarios are expected to generate tsunamis, and submarine landslides could be triggered by seismic motion. In addition to these past studies, numerical modeling has been applied to tsunami generation and propagation from combined earthquake and landslide sources. In this study, tsunami hazards are evaluated from both individual and combined cases of submarine earthquakes and landslides through numerical tsunami simulations with a grid size of 90 m for bathymetry and topography data for the entire Marmara Sea region and validated with historical observations from the 1509 and 1894 earthquakes. This study implements TUNAMI model with a two-layer model to conduct numerical tsunami simulations, and the numerical results show that the maximum tsunami height could reach 4.0 m along Istanbul shores for a full submarine rupture of the NAF, with a fault slip of 5.0 m in the eastern and western basins of the Marmara Sea. The maximum tsunami height for landslide-generated tsunamis from small, medium, and large of initial landslide volumes (0.15, 0.6, and 1.5 km3, respectively) could reach 3.5, 6.0, and 8.0 m, respectively, along Istanbul shores. Possible tsunamis from submarine landslides could be significantly higher than those from earthquakes, depending on the landslide volume significantly. These combined earthquake and landslide sources only result in higher tsunami amplitudes for small volumes significantly because of amplification within the same tsunami amplitude scale (3.0-4.0 m). Waveforms from all the coasts around the Marmara Sea

  4. Postglacial floodings of the Marmara Sea: molluscs and sediments tell the story

    NASA Astrophysics Data System (ADS)

    Büyükmeriç, Yeşim

    2016-08-01

    The early Holocene marine flooding of the Black Sea has been the subject of intense scientific debate since the "Noah's Flood" hypothesis was proposed in the late 1990s. The chronology of the flooding is not straightforward because the connection between the Black Sea and the Mediterranean Sea involves the intermediate Marmara Sea Basin via two sills (Dardanelles and Bosphorus). This study explores the chronology of late Pleistocene-Holocene flooding by examining sedimentary facies and molluscs from 24 gravity cores spanning shelf to slope settings in the southern Marmara Sea Basin. A late Pleistocene Ponto-Caspian (Neoeuxinian) mollusc association is found in 12 of the cores, comprising 14 mollusc species and dominated by brackish (oligohaline-lower mesohaline) endemic taxa (dreissenids, hydrobiids). The Neoeuxinian association is replaced by a Turritella- Corbula association at the onset of the Holocene. The latter is dominated by marine species, several of which are known to thrive under dysoxic conditions in muddy bottoms. This association is common in early Holocene intervals as well as sapropel intervals in younger Holocene strata. It is an indicator of low-salinity outflows from the Black Sea into the Marmara Sea that drive stratification. A marine Mediterranean association (87 species) represents both soft bottom and hard substrate faunas that lived in well-ventilated conditions and upper mesohaline-polyhaline salinities (ca. 25 psu). Shallower areas were occupied by hard substrate taxa and phytopdetritic communities, whereas deeper areas had soft bottom faunas. The middle shelf part of the northern Gemlik Gulf has intervals with irregular and discontinuous sedimentary structures admixed with worn Neoeuxinian and euryhaline Mediterranean faunas. These intervals represent reworking events (slumping) likely related to seismic activity rooted in the North Anatolian Fault system. The core data and faunas indicate an oscillating postglacial sea-level rise and

  5. Gas geochemistry and tectonics around the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Italiano, Francesco; Woith, Heiko; Seyis, Cemil; Pizzino, Luca; Sciarra, Alessandra; Favali, Paolo

    2015-04-01

    During two fluid sampling campaigns in 2013 and 2014, around 60 thermal and mineral water springs/wells in the wider Marmara region were visited jointly by INGV, TÜBITAK and GFZ scientists in the frame of MARsite (MARMARA Supersite, 7th FP EC-funded project, grant n° 308417). Gas samples were collected and analyzed for the main chemical composition as well as their isotopic composition (He and C). Gases were taken from thermal and cold springs located in coincidence of segments of the Northern and Southern branches of the Northern Anatolian Fault Zone (NAFZ). Bubbling gases were collected when available, in all the other cases the gas phase was extracted from water samples collected on that purpose. The results confirm that over the Marmara area the majority of the gases are a binary mixture of atmospheric and deep originated volatiles. CO2 is normally the main gas species. Its concentration decrease, due to GWI (gas-water interactions), increases the relative concentration of N2 and other less soluble gases. A high CO2 content indicates minor interactions, thus, the easier and faster is the path from the deep layers toward the earth's surface, the lower are the interactions. The volatiles keep their pristine composition. Faults represent a preferential way for rising volatiles due to local high permeability. The 3He/4He ratios ranging from 0.1 to 4.8Ra (Ra=3He/4He atmospheric ratio) indicate the presence of mantle contribution. The highest ratio was found at the eastern end of the Ganos fault. Mantle degassing is not obvious in non-volcanic areas, however the measured helium isotopic ratios indicate mantle degassing possibility through lithospheric faults. All the information indicate that the fluids circulating over this area are the result of fluid mixing at variable extents of three end-members: mantle, crust and atmosphere. We propose that while the composition of shallow fluids is a matter of the local geology (for example the hosting rocks where thermal

  6. Estimating shipping emissions in the region of the Sea of Marmara, Turkey.

    PubMed

    Deniz, Cengiz; Durmuşoğlu, Yalçin

    2008-02-01

    Ship emissions are significantly increasing globally and have remarkable impact on air quality on sea and land. These emissions contribute serious adverse health and environmental effects. Territorial waters, inland seas and ports are the regions most affected by ship emissions. As an inland sea the Sea of Marmara is an area that has too much ship traffic. Since the region of the Marmara is highly urbanized, emissions from ships affect human health and the overall environment. In this paper exhaust gas emissions from ships in the Sea of Marmara and the Turkish Straits are calculated by utilizing the data acquired in 2003. Main engine types, fuel types, operations types, navigation times and speeds of vessels are taken into consideration in the study. Total emissions from ships in the study area were estimated as 5,451,224 t y(-1) for CO(2), 111,039 t y(-1) for NO(x), 87,168 t y(-1) for SO(2), 20,281 t y(-1) for CO, 5801 t y(-1) for VOC, 4762 t y(-1) for PM. The shipping emissions in the region are equivalent to 11% of NO(x) 0.1% of CO and 0.12% of PM of the corresponding total emissions in Turkey. The shipping emissions in the area are 46% of NO(x), 25% of PM and 1.5% of CO of road traffic emissions in Turkey data between which and correspond to a higher level than aircraft emissions and rail emissions in Turkey.

  7. Paleo-environmental controls on cold seep carbonate authigenesis in the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Crémière, Antoine; Bayon, Germain; Ponzevera, Emmanuel; Pierre, Catherine

    2013-08-01

    The factors controlling fluid emission dynamics at ocean margins are poorly understood. In particular, there are significant uncertainties on how fluid seepage at cold seeps may have responded to abrupt environmental changes in the geological past. This study reports on a detailed geochemical investigation of seafloor carbonate crusts sampled at cold seeps along the submerged part of the North Anatolian Fault system in the Sea of Marmara - an inland sea, which has experienced major paleo-environmental changes over the last deglaciation period. We also analyzed a series of authigenic carbonate concretions recovered from two sediment cores at the Western-High ridge, an active fluid venting area. The ages of seafloor carbonate crusts derived from isochron U-Th dating cover the last 7 kyr, suggesting that fluid activity along the fault system remained continuous over that time interval. In the sediment cores, carbonate concretions are concentrated at the lacustrine-to-marine transition, which corresponds to the period when Mediterranean waters flowed into the Marmara Basin about 12-14 kyr ago. U-Th isotopic data indicate that most of these concretions formed later during the Holocene, around 9-10 kyr ago, a period coinciding with an important anoxic event that led to the deposition of a sapropel layer in the Sea of Marmara. Based upon these results, we suggest that the absence of carbonate concretions in the lacustrine sediment unit indicates that dissolved sulfate concentrations in the Marmara lake pore waters during glacial time were too low to promote significant anaerobic methane oxidation, thereby preventing sedimentary carbonate authigenesis. In contrast, the progressive inflow of Mediterranean waters into the glacial Marmara lake after 15 ka provided a source of dissolved sulfate that allowed anaerobic oxidation of methane to proceed within the anoxic sediment. Importantly, the synchronism between the main phase of authigenic carbonate precipitation at the

  8. Recalculated probability of M ≥ 7 earthquakes beneath the Sea of Marmara, Turkey

    USGS Publications Warehouse

    Parsons, T.

    2004-01-01

    New earthquake probability calculations are made for the Sea of Marmara region and the city of Istanbul, providing a revised forecast and an evaluation of time-dependent interaction techniques. Calculations incorporate newly obtained bathymetric images of the North Anatolian fault beneath the Sea of Marmara [Le Pichon et al., 2001; Armijo et al., 2002]. Newly interpreted fault segmentation enables an improved regional A.D. 1500-2000 earthquake catalog and interevent model, which form the basis for time-dependent probability estimates. Calculations presented here also employ detailed models of coseismic and postseismic slip associated with the 17 August 1999 M = 7.4 Izmit earthquake to investigate effects of stress transfer on seismic hazard. Probability changes caused by the 1999 shock depend on Marmara Sea fault-stressing rates, which are calculated with a new finite element model. The combined 2004-2034 regional Poisson probability of M≥7 earthquakes is ~38%, the regional time-dependent probability is 44 ± 18%, and incorporation of stress transfer raises it to 53 ± 18%. The most important effect of adding time dependence and stress transfer to the calculations is an increase in the 30 year probability of a M ??? 7 earthquake affecting Istanbul. The 30 year Poisson probability at Istanbul is 21%, and the addition of time dependence and stress transfer raises it to 41 ± 14%. The ranges given on probability values are sensitivities of the calculations to input parameters determined by Monte Carlo analysis; 1000 calculations are made using parameters drawn at random from distributions. Sensitivities are large relative to mean probability values and enhancements caused by stress transfer, reflecting a poor understanding of large-earthquake aperiodicity.

  9. Measurement of natural and 137Cs radioactivity concentrations at Izmit Bay (Marmara Sea), Turkey

    NASA Astrophysics Data System (ADS)

    Öksüz, I.; Güray, R. T.; Özkan, N.; Yalçin, C.; Ergül, H. A.; Aksan, S.

    2016-03-01

    In order to determine the radioactivity level at Izmit Bay Marmara Sea, marine sediment samples were collected from five different locations. The radioactivity concentrations of naturally occurring 238U, 232Th and 40K isotopes and also that of an artificial isotope 137Cs were measured by using gamma-ray spectroscopy. Preliminary results show that the radioactivity concentrations of 238U and 232Th isotopes are lower than the average worldwide values while the radioactivity concentrations of the 40K are higher than the average worldwide value. A small amount of 137Cs contamination, which might be caused by the Chernobyl accident, was also detected.

  10. OBS development for long term observation in the Marmara Sea, NW Turkey

    NASA Astrophysics Data System (ADS)

    Takahashi, Narumi; Shimizu, Satoshi; Maekawa, Takuya; Kalafat, Dogan; Pinar, Ali; Citak, Seckin; Kaneda, Yoshiyuki

    2015-04-01

    We have carried out a collaboration study between Japan and Turkey since 2013, which is one of SATREPS projects, "Earthquake and Tsunami Disaster Mitigation in The Marmara Region and Disaster Education in Turkey". The main objective of this project is to reduce risk brought by earthquakes and tsunamis. In particular, the North Anatolian Fault system runs through the Marmara sea and it is expected that the seismic gap exists there according to past seismic studies. The details of seismicity distribution in the Marmara Sea is, however, still insufficient to construct fault model along the active faults. Therefore, we prepare ten ocean bottom seismographs (OBSs) to realize long term observation. We aim to identify size and depth of seismogenic zones using micro seismicity. In addition, we need to cover relative broad area from off-shore Istanbul city to the western end of the Marmara Sea. To clear these conditions, OBS specifications we need are high dynamic range and low instrument noise to observe micro seismicity, low electrical consumption to realize long term observation of over one year, high cost performance to cover the broad area for OBS installation, low cost implementation, and good operability to treat by relatively small number of persons. All items, which are three components velocity sensor, batteries, a recorder, a GPS receiver, a transponder and its transducer to control OBS retrieval, a flasher and a beacon, are installed in the 17 inches glass sphere. The natural frequency of the velocity sensor is 4.5 Hz and the frequency range of our OBS is from 4.5 Hz to 250 Hz. Data sampling is selectable among 100 Hz, 250 Hz and 500 Hz. Because our OBS is deployed by free fall, accuracy of the OBS clock is essentially one of important factors, and it is less than 0.1 ppm. And the resolution of A/D conversion performed on the recorder is 24 bit and we keep the dynamic range of over 135 dB. These data is stored on a semiconductor memory and the capacity is over

  11. An improved earthquake catalogue in the Marmara Sea region, Turkey, using massive template matching

    NASA Astrophysics Data System (ADS)

    Matrullo, Emanuela; Lengliné, Olivier; Schmittbuhl, Jean; Karabulut, Hayrullah; Bouchon, Michel

    2016-04-01

    After the 1999 Izmit earthquake, the Main Marmara Fault (MMF) represents a 150 km unruptured segment of the North Anatolian Fault located below the Marmara Sea. One of the principal issue for seismic hazard assessment in the region is to know if the MMF is totally or partially locked and where the nucleation of the major forthcoming event is going to take place. The area is actually one of the best-instrumented fault systems in Europe. Since year 2007, various seismic networks both broadband, short period and OBS stations were deployed in order to monitor continuously the seismicity along the MMF and the related fault systems. A recent analysis of the seismicity recorded during the 2007-2012 period has provided new insights on the recent evolution of this important regional seismic gap. This analysis was based on events detected with STA/LTA procedure and manually picked P and S wave arrivals times (Schmittbuhl et al., 2015). In order to extend the level of details and to fully take advantage of the dense seismic network we improved the seismic catalog using an automatic earthquake detection technique based on a template matching approach. This approach uses known earthquake seismic signals in order to detect newer events similar to the tested one from waveform cross-correlation. To set-up the methodology and verify the accuracy and the robustness of the results, we initially focused in the eastern part of the Marmara Sea (Cinarcik basin) and compared new detection with those manually identified. Through the massive analysis of cross-correlation based on the template scanning of the continuous recordings, we construct a refined catalog of earthquakes for the Marmara Sea in 2007-2014 period. Our improved earthquake catalog will provide an effective tool to improve the catalog completeness, to monitor and study the fine details of the time-space distribution of events, to characterize the repeating earthquake source processes and to understand the mechanical state of

  12. Geology and seismotectonics of the North-Anatolian Fault in the Sea of Marmara: implications for seismic hazards

    NASA Astrophysics Data System (ADS)

    Gasperini, Luca; Cedro, Vincenzo; Polonia, Alina; Cruise Party, Marmara

    2016-04-01

    Based on high-resolution multibeam and seismic reflection data recently collected and analysed in the frame of Marsite (New Directions in Seismic Hazard Assessment through Focused Earth Observation in the Marmara Supersite) EC FP7 Project, in conjunction with a large set of geophysical and geological data collected starting from 1999, we compiled a new morphotectonic map of the submerged part of the North-Anatolian Fault system (NAF) in the Sea of Marmara. Data analysis allowed us to recognize active fault segments and their activity at the scale of 10 ka, taking as stratigraphic reference the base of the latest marine ingression, which constitutes a clear marker in the sedimentary sequence of the Sea of Marmara. This is mainly due to the fact the Sea of Marmara was a fresh water lake during the Last Glacial Maximum, and switched to a marine environment when the global sea level reached to the -85 m relative to present day and crossed the Dardanelles sill during the transgression. The passage from lacustrine to marine environment is marked by a typical unconformity in high-resolution seismic profiles, which can be correlated over the entire Marmara basin. According to the average recurrence time for major earthquake along the NAF, the time interval of 10 ka should include several earthquake cycle and is representative of the seismotectonic behavior of the fault at geological time scales. Given the relatively high deformation rates relative to in relative to sediment supply, most active tectonic structures have a morphological expression at the seafloor. This allowed us to correlate deformations from a seismic section to the adjacent. Fault strands not affecting the Holocene sequence were considered inactive. Three types of deformation patterns were observed and classified: almost purely E-W oriented strike-slip segments; NE-SW oriented trans-pressional structures; NW-SE trending trans-tensional features. Segmentation of the so-called Main Marmara Fault in the Sea

  13. Detailed spatial distribution of microearthquakes beneath the Marmara Sea, Turkey, deduced from long-term ocean bottom observation

    NASA Astrophysics Data System (ADS)

    Yamamoto, Yojiro; Takahashi, Narumi; Pinar, Ali; Kalafat, Doǧan; Citak, Seckin; Comoglu, Mustafa; Polat, Remzi; Çok, Özkan; Ogutcu, Zafer; Suvariklı, Murat; Tunc, Suleyman; Gürbüz, Cemil; Turhan, Fatih; Ozel, Nurcan; Kaneda, Yoshiyuki

    2016-04-01

    The North Anatolian Fault (NAF) crosses the Marmara Sea in E-W direction, accommodating about 25 mm/yr of right-lateral motion between Anatolia and the Eurasian plate. There are many large earthquakes along the 1500 km long NAF repeatedly occurred and interacted each other. The recent large northern Aegean earthquake with Mw=6.9 filled one of the last two seismic gaps on NAF that experienced extraordinary seismic moment release cycle during the last century and confirmed a remained blank zone in the Marmara Sea. However, this segment keeps its mystery due to its underwater location. Earthquake hazard and disaster mitigation studies in Marmara region are sensitive to detailed information on fault geometry and its stick-slip behavior beneath the western Marmara Sea. We have started ocean bottom seismographic observations to obtain the detailed information about fault geometry and its stick-slip behavior beneath the western Marmara Sea, as a part of the SATREPS collaborative project between Japan and Turkey namely "Earthquake and Tsunami Disaster Mitigation in the Marmara Region and Disaster Education in Turkey". The target area spans from western Marmara Sea to offshore Istanbul along the NAF. In the beginning of the project, we deployed ten Ocean Bottom Seismographs (OBSs) between the Tekirdag Basin and the Central Basin (CB) in September 2014. Then, we added five Japanese OBSs and deployed them in the western end of the Marmara Sea and in the eastern CB to extend the observed area in March 2015. We retrieved all 15 OBSs in July 2015 and deployed them again in the same locations after data retrieve and battery maintenance. From continuous OBS records, we could detect more than 700 events near the seafloor trace of NAF during 10 months observation period whereas land-seismic network could detect less than 200 events. We estimated the micro-earthquake location using manual-picking arrival times incorporating station corrections. The tentative results show

  14. Last Glacial - Holocene stratigraphic development at the Marmara Sea exit of the Bosphorus Strait, Turkey

    NASA Astrophysics Data System (ADS)

    Köprülü, Kerem; Alpar, Bedri; Vardar, Denizhan

    2016-03-01

    High resolution Chirp and Sparker data allowed definition and mapping of distinct seismic units in the shallow sediment record (~100 ms) acquired from the southern exit of the Bosphorus Strait; a dynamic depositional environment. The bottommost unit observed in the Chirp data (unit-3) is made up of marine-lacustrine sediments thinning seaward and onlaps the basement rocks which are represented by folded strata in the Sparker data, possibly lower to middle Pleistocene age. It is overlain by a series of prograding deposits along the shelf (unit-2) referring to sediment input from the northern sector depending on the water levels of the paleo Marmara lake's during MIS 3. The uppermost deposits (unit-1) close to the Bosphorus Strait were represented by three separate subunits, unlike to relatively thin drape of sediments observed at the other places in the surrounding regions. The detailed definition of these subunits deduced from the closely-spaced reflection profiles and available radiocarbon ages helped to explain the history of the latest stratigraphic development depending on the connections between the Black Sea and the Sea of Marmara. In addition to the previously proposed major conduits, which controlled the sedimentary deposition at the southern exit of the Bosphorus, namely the Bosphorus Strait and Kurbağalıdere River, another submarine sedimentary pathway at the eastern bank of the strait's channel seems to have delivered sediments directly into the basin.

  15. 2-D Stress Accumulation Analysis of the North Anatolian Fault East of the Marmara Sea

    NASA Astrophysics Data System (ADS)

    Karimi, B.; McQuarrie, N.; Harbert, W.; Lin, J.

    2011-12-01

    On August 17th, 1999, a magnitude 7.4 earthquake shook the city of Kocaeli (Izmit), Turkey killing over 17,000 people. The epicenter was approximately 100-km east of Turkey's largest city, Istanbul, along the North Anatolian Fault (NAF) system. This 1600-km long, strike-slip boundary divides the Anatolian plate and the Eurasian plate. The NAF slips at an average rate of 2-3-cm y-1, and has an earthquake recurrence interval of approximately 300 years. To further understand the NAF system and its dynamics, a simplified 2-D mesh model was developed to describe fault stress accumulation along an ~110-km stretch of the NAF system east of the Marmara Sea. This region was selected because it is where two sets of faults within the NAF system converge, and then diverge. One set diverges to the NW to bound the northern rim of the Marmara Sea, while the second set continues to the SW along the southern rim of the Marmara Sea. The 2-D mesh separates the study area into three geologic provinces defined by these faults: the Istanbul Zone, the Armatlu-Almacik Zone, and the Sakarya Zone. The resulting mesh was then processed using the Numerical Manifold Method (NMM) and PyLith, a finite element code deformation software. The NMM and PyLith simulations model the stress field in the region by employing surface fault geometry, rock physics parameters of the surface geology, and relative plate motions as determined by GPS velocities from Turkey's extensive network of GPS stations. Surface geology was simplified into the three rock types, and rock physics parameters were assigned using general physical parameters for each rock type and extrapolating further data from the Canadian Rock Physics Database. For the three zones, an average value for density and P-wave velocity was assigned using this database, and these averaged values were used to calculate S-wave velocity, shear modulus, bulk modulus, Young's modulus, Poisson's ratio, and Lamé's first parameter for use in processing the

  16. Installation and Initial Results of Borehole Strainmeters around the Marmara Sea in Turkey.

    NASA Astrophysics Data System (ADS)

    Mencin, David; Bohnhoff, Marco; Ozener, Haluk; Mattioli, Glen; Bilham, Roger; Johnson, Wade; Gottlieb, Mike; Van Boskirk, Elizabeth; Aracel, Digdem; Bulut, Fatih; Bal, Osman

    2016-04-01

    Twice in the past 1000 years a sequence of damaging earthquakes has propagated during the course of a few decades along the North Anatolian fault (NAF) in Turkey towards Istanbul, with the final earthquake in the sequence catastrophically destroying the city. This occurred most recently in 1509 when the population was only about 200,000 yet ten thousand people died. The population of greater Istanbul is now 20 million, building stock more fragile, and the last earthquake of the current westward propagating sequence is considered geologically imminent. An opportunity to enhance the detection capability of a suite of deep seismometers installed near Istanbul has arisen, that will permit us to observe, characterize, and possibly predict the moment of imminent failure along the NAF, as well as monitor the tectonic processes leading to this failure. As an augmentation of the Geophysical Observatory at the North Anatolian Fault (GONAF), UNAVCO installed two continuous creepmeters and six borehole strainmeters between July 2014 and October 2015 into boreholes provided by the several international sponsors, including NSF, GFZ, AFAD and Bogazici University Kandilli Observatory. The entire geophysical sensor network is collectively referred to as GeoGONAF. The borehole strainmeters enhance the ability of the scientific instrumentation to monitor ultra-slow process near the probable source zone of the Mw>7 earthquake that is soon expected beneath the Marmara Sea. The strainmeters and creepmeters allow us to make geodetic observations of this segment of the fault before, during and after a large earthquake, which combined with the seismic data from GONAF will provide valuable data for understanding earthquake processes. Installed instruments have already recorded both local and teleseismic events and observed creep events on the on-shore segments of the NAF to the East of the Marmara. In addition we have seen typical hydrological loading signals associated with normal modes of

  17. The sedimentary records of Holocene environmental changes from the Central High of the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Filikci, Betul; Çağatay, Namık; Kadir Eriş, Kürşad; Akyol, Mustafa; Yalamaz, Burak; Uçarkuş, Gülsen; Henry, Pierre

    2015-04-01

    The Sea of Marmara (SoM) is located between the Aegean Sea and the Black Sea, to which it is connected via the Istanbul (Bosphorus) and Canakkale (Dardanelles) straits having sill depths of 65 and 35 m, respectively. It has a two-way water mass exchange with a permanent pycnocline located at 20-25 m water depth. With the objective of determining Holocene paleoenvironmental changes, we studied a 8.36 m-long piston core recovered from the Central High of the SoM at a water depth of 835 m, using multiproxy analyses such as total organic and inorganic carbon, high resolution µ-XRF core scanner analysis, grain size, magnetic susceptibility and density. A 2 cm-thick tephra layer with high K and Zr and relatively low magnetic susceptibility occurs at 2.1 meter below sea floor (mbsf), which is correlated with the Avellino (Somma-Vesuvius, Italy) eruption dated at 3.9 ka BP, according to the previous studies. Using this age and assuming a uniform sedimentation rate, the base of the core dates back to ca 8 ka BP. The core includes organic-rich (sapropelic) sediments with 1.5 % to 2.2%) in its top 3.5 m and bottom 1 m. Sapropelic layers are olive green and in part laminated, and contain occasional reddish brown spots and laminae formed by oxidation of iron monosulphides. The core also contains some few mm- to cm-thick sandy-silty mass-flow units below 2.4 mbsf, some of which could have been triggered by the earthquake activity on the Central High segment of the North Anatolian Fault, just a few km away from the core location. Variations in Ca-Ti ratio suggest millennial-scale climatic changes during the Holocene. Keywords: Sea of Marmara, Holocene paleoenvironmental records, tephra, turbidites, TOC analysis, XRF analysis, physical properties.

  18. Offshore seismicity in the western Marmara Sea, Turkey, revealed by ocean bottom observation

    NASA Astrophysics Data System (ADS)

    Yamamoto, Yojiro; Takahashi, Narumi; Citak, Seckin; Kalafat, Doǧan; Pinar, Ali; Gürbüz, Cemil; Kaneda, Yoshiyuki

    2015-04-01

    The North Anatolian Fault (NAF) extends 1600 km westward from a junction with the East Anatolian Fault at the Karliova Triple Junction in eastern Turkey, across northern Turkey and into the Aegean Sea, accommodating about 25 mm/yr of right-lateral motion between Anatolia and the Eurasian plate. Since 1939, devastating earthquakes with magnitude greater than seven ruptured NAF westward, starting from 1939 Erzincan (Ms=7.9) at the eastern Turkey and including the latest 1999 Izmit-Golcuk (Ms=7.7) and the Duzce (Ms=7.4) earthquakes in the Marmara region. Considering the fault segments ruptured by the May 24th, 2014 Northern Aegean earthquake (Mw=6.9), the only un-ruptured segments left behind the 1600 km long NAF locate beneath the Marmara Sea and those segments keep their mystery due to their underwater location. To consider the earthquake hazard and disaster mitigation, the detailed information about fault geometry and its stick-slip behavior beneath the western Marmara Sea is very important. Thus, we started to operate a series of ocean bottom seismographic (OBS) observations to estimate the fault geometry from microearthquake distribution. As a first step, we deployed 3 pop-up type OBSs on 20th of March 2014 as a trial observation, and recovered them on 18th of June 2014. Although one of the OBSs worked only 6 days from the start of the observation, other two OBSs functioned properly during the whole 3-month observation period. We first searched for the microearthquakes missing by the land seismic network and estimated their precious location by using the initial 6 days data, i.e., using all the temporary OBS stations. Although there are only 3 earthquakes listed on the Kandilli Observatory and Earthquake Research Institute (KOERI) catalogue, we could identify 41 earthquakes with more than 5 picking data of P and S first arrivals, and two-third of them located within the OBS network. We found the earthquake cluster along the main NAF and whose depth interval is 12

  19. Authigenic carbonate crusts and chimneys along the North Anatolian Fault in the Sea of Marmara, Turkey

    NASA Astrophysics Data System (ADS)

    Yıldız, Güliz; Namık Çaǧatay, M.

    2016-04-01

    The Sea of Marmara is located on the North Anatolian Fault (NAF) fault zone that is a major continental transform plate boundary. It has ca. 1250 m-deep Tekirdag, Central and Cinarcik basins that are separated by two NE-SW trending Central and Western Highs. Extensive cold seeps occur along the active fault segments of the NAF in the deep basins and highs, which are associated with authigenic carbonate crusts, carbonate chimneys and mounds, black sulphidic sediments, and local gas hydrates and oil seepage. The cold seep sites were observed and sampled during the Nautile submersible and Victor 6000 Remotely Operated Vehicle (ROV) dives carried out during MARNAUT and MARSITE cruises in 2007 and 2014, respectively. Here, we report the mineralogical and stable isotopic composition of the authigenic carbonates and discuss their environmental conditions and mechanisms of formation. The carbonate crusts range up to 5 cm in thickness and the chimneys and mounds are up to 2 m high. Some chimneys are active emitting fresh to brackish water at ambient bottom water temperatures (˜ 14° C). The carbonate crusts occur as a pavements, and are commonly covered with black sulphidic sediments and bacterial mats that accommodate a rich chemosynthetic community of bivalves, sea urchins and marine annelid worms (Polychaeta). The authigenic carbonates commonly consist mainly of aragonite, but in a few instances contain subequal amounts of aragonite and calcite. High Mg-calcite is usually a minor to trace component, except in one sample in which it is present as a cement of mudstone. In the active methane emission zones, the sulphate/methane boundary occurs at or close to the seafloor, whereas elsewhere in the Sea of Marmara, the same boundary is located at 2-5 m below the seafloor. This, together with very light stable carbon isotope values (δ13C=-29.8 to - 46.3 ‰ V-PDB), indicates that the anaerobic oxidation of high methane flux emitted from the active faults is the major process

  20. Is the Marmara Sea segment of the North Anatolian Fault Creeping or loading ?

    NASA Astrophysics Data System (ADS)

    Klein, Emilie; Masson, Frédéric; Duputel, Zacharie; Yavasoglu, Hakan

    2016-04-01

    During the last century, the North Anatolian Fault has experienced a migrating Mw>7 earthquakes sequence that ruptured about 1000 km of the fault westward. The last major earthquakes occurred in 1999 in Izmit (Mw7.4) and Duzce (Mw7.2). Only the segments located directly offshore of Istanbul, in the Marmara Sea, remain unbroken in this series of events. This region represents a major issue in terms of seismic hazard with more than 13 millions inhabitants in the city of Istanbul. However, a strong controversy remains over whether the central segment of the Main Marmara Fault is locked and likely to experience a major earthquake, or not. Recent studies based on geodetic data suggest indeed that, contrary to the Prince's Island segment which is fully locked, the central segment is accommodating the strain by aseismic fault creep. So it has not the potential to generate a Mw ~7 event. These results, mostly based on relatively simple strain accumulation models over infinitely long faults, is contested by a recent seismic data study, which suggests on the contrary that this fault segment is fully locked and mature to generate such a great earthquake. In this study, we revisit the available geodetic data considering a 3D geometry of the fault, allowing to take into account the lateral variations of behavior along the fault. In particular, we evaluate if current geodetic datasets are sufficient to constrain strain accumulation and thus to conclude about the seismic hazard in the region.

  1. Integrative study of a new cold-seep mussel (Mollusca: Bivalvia) associated with chemosynthetic symbionts in the Marmara Sea

    NASA Astrophysics Data System (ADS)

    Ritt, Bénédicte; Duperron, Sébastien; Lorion, Julien; Sara Lazar, Cassandre; Sarrazin, Jozée

    2012-09-01

    Recently, small Idas-like mussels have been discovered living on carbonate crusts associated with cold-seeps in the Marmara Sea. These mussels, here referred to as Idas-like nov. sp., differ morphologically and genetically from another species identified as Idas aff. modiolaeformis, living in the same type of ecosystem in the Nile Deep-Sea Fan (eastern Mediterranean Sea). A phylogenetic analysis confirms the distinction between the two species, which belong to highly divergent lineages. Carbon stable isotope values, as well as the detection of thiotroph-related bacteria in the gill tissue, support the presence of a symbiotic, thiotroph-derived nutrition. In contrast, Idas aff. modiolaeformis displays six different types of symbionts. Finally our size-frequency data suggest that the recruitment is continuous in the examined area. The present study extends the documented distribution of symbiont-bearing mussels to the Marmara Sea, and contributes to the characterisation of biological communities in this recently explored area.

  2. Dynamics of the Circulation in the Sea of Marmara: Numerical Modeling Experiments and Observations from the Turkish Straits System Experiment

    DTIC Science & Technology

    2011-01-01

    therefore directly impact- ing the Sea ofMarmara region ( Trigo et al. 1999; Karaca et al. 2000). Some other disturbances dissipate on the western...Anatolian coastal area and other cyclones continue crossing Turkey eventually reaching the easternmost part of the Black Sea ( Trigo et al. 1999, 2002... Trigo IF, Davies TD, Bigg GR (1999) Objective climatology of cyclones in the Mediterranean region. J Clim 12:1685–1696 Trigo IF, Bigg GR, Davies TD

  3. Microseismicity at the North Anatolian Fault in the Sea of Marmara offshore Istanbul, NW Turkey

    USGS Publications Warehouse

    Bulut, Fatih; Bohnhoff, Marco; Ellsworth, William L.; Aktar, Mustafa; Dresen, Georg

    2009-01-01

    The North Anatolian Fault Zone (NAFZ) below the Sea of Marmara forms a “seismic gap” where a major earthquake is expected to occur in the near future. This segment of the fault lies between the 1912 Ganos and 1999 İzmit ruptures and is the only NAFZ segment that has not ruptured since 1766. To monitor the microseismic activity at the main fault branch offshore of Istanbul below the Çınarcık Basin, a permanent seismic array (PIRES) was installed on the two outermost Prince Islands, Yassiada and Sivriada, at a few kilometers distance to the fault. In addition, a temporary network of ocean bottom seismometers was deployed throughout the Çınarcık Basin. Slowness vectors are determined combining waveform cross correlation and P wave polarization. We jointly invert azimuth and traveltime observations for hypocenter determination and apply a bootstrap resampling technique to quantify the location precision. We observe seismicity rates of 20 events per month for M < 2.5 along the basin. The spatial distribution of hypocenters suggests that the two major fault branches bounding the depocenter below the Çınarcık Basin merge to one single master fault below ∼17 km depth. On the basis of a cross-correlation technique we group closely spaced earthquakes and determine composite focal mechanisms implementing recordings of surrounding permanent land stations. Fault plane solutions have a predominant right-lateral strike-slip mechanism, indicating that normal faulting along this part of the NAFZ plays a minor role. Toward the west we observe increasing components of thrust faulting. This supports the model of NW trending, dextral strike-slip motion along the northern and main branch of the NAFZ below the eastern Sea of Marmara.

  4. Tephra record from the Sea of Marmara for the last 70 ka and its paleoceanographic implications

    NASA Astrophysics Data System (ADS)

    Cagatay, M.; Wulf, S.; Guichard, F.; Ozmaral, A.; Sancar; Akçer-Ön, S.; Henry, P.; Gasperini, L.

    2013-12-01

    Sea of Marmara (SoM) is a gateway between the Mediterraean and Black seas, and a tectonically active basin located on a transform plate boundary. Tephra record in the SoM is therefore very important for dating palaeoceanographic, paleoclimatic and tectonic events. We report three tephra units in cores from the SoM extending back to ca 70 ka BP and including an upper marine and a lower lacustrine units separated by a 12 ka (uncalib.) boundary. The uppermost tephra unit is up to 8 mm thick layer in the marine unit. It is heterogenous phonolitic with high total alkali content of 12.4-15.7 wt % and K2O/Na2O of 0.9 to 1.2. The middle and lower tephra layers occur in the lacustrine unit in ca 29 m-long Core MD-01-2430. The middle tephra (MT-1) is a 70 mm-thick homogeneously rhyolitic layer. The lower tephra (MT-2) is 140 mm thick and has a phonolitic-trachytic composition with CaO content of 1.7-1.9 wt % and bimodal K2O/Na2O of 1.0-1.4. Using their geochemical composition and stratigraphic analysis, we assign the tephra units, from top to bottom, to Vesuvius AP2 Pumice, Santorini Cape Riva and Campanian Ignimbrite, which have been previously dated at 3.5 ka BP, 21.95 ka BP, and 39.3 ka BP (all calender ka). The continuous sedimentary record in the Core MD-01-2430 covering the last ca 70 ka indicates that the SoM was lacustrine, disconnected from the Mediterraean Sea during MIS4, MIS3 and most of MIS2. This implies that the sill depth of the Çanakkale Strait (Dardanelles) was shallower than the present-day -65 m sill depth during MIS3 and MIS4. Figure 1: Morphotectonic map of the Sea of Marmara showing location of the studied cores (red stars). Figure 2: Geochemical biplots of tephra glass composition. a) Total alkali silica diagram b) FeO versus total alkalies for allocating cryptotephras from core MNTKS34 and ML01 to the AP2 tephra from Vesuvius. c) FeO versus CaO for correlating tephra MT1 with the Y-2 tephra from Santorini. d) SiO2 versus CaO for discriminating the

  5. Seismotectonics of the Armutlu peninsula (Marmara Sea, NW Turkey) from geological field observation and regional moment tensor inversion

    NASA Astrophysics Data System (ADS)

    Kinscher, J.; Krüger, F.; Woith, H.; Lühr, B. G.; Hintersberger, E.; Irmak, T. S.; Baris, S.

    2013-11-01

    The Armutlu peninsula, located in the eastern Marmara Sea, coincides with the western end of the rupture of the 17 August 1999, İzmit MW 7.6 earthquake which is the penultimate event of an apparently westward migrating series of strong and disastrous earthquakes along the NAFZ during the past century. We present new seismotectonic data of this key region in order to evaluate previous seismotectonic models and their implications for seismic hazard assessment in the eastern Marmara Sea. Long term kinematics were investigated by performing paleo strain reconstruction from geological field investigations by morphotectonic and kinematic analysis of exposed brittle faults. Short term kinematics were investigated by inverting for the moment tensor of 13 small to moderate recent earthquakes using surface wave amplitude spectra. Our results confirm previous models interpreting the eastern Marmara Sea Region as an active transtensional pull-apart environment associated with significant NNE-SSW extension and vertical displacement. At the northern peninsula, long term deformation pattern did not change significantly since Pliocene times contradicting regional tectonic models which postulate a newly formed single dextral strike slip fault in the Marmara Sea Region. This area is interpreted as a horsetail splay fault structure associated with a major normal fault segment that we call the Waterfall Fault. Apart from the Waterfall Fault, the stress strain relation appears complex associated with a complicated internal fault geometry, strain partitioning, and reactivation of pre-existing plane structures. At the southern peninsula, recent deformation indicates active pull-apart tectonics constituted by NE-SW trending dextral strike slip faults. Earthquakes generated by stress release along large rupture zones seem to be less probable at the northern, but more probable at the southern peninsula. Additionally, regional seismicity appears predominantly driven by plate boundary

  6. Sedimentological and Geochemical Characteristics of Turbidites Related to Earthquake Activity in the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Cagatay, M.; Belucci, L.; Polonia, A.; Sancar, U.; Eris, K.; Gasperini, L.; Gorur, N.; Henry, P.; Zitter, T. A.; Geli, L.; Tryon, M. D.

    2008-12-01

    The Sea of Marmara (SoM) is a tectonically active basin being located on a major continental transform fault boundary between the Eurasian and Anatolian plates. It consists of three transtensional major subbasins in excess of -1250 m and smaller ones with -100 to -200 m forming the E-W elongated gulfs and bays. The major subbasins have steep slopes, especially in the north, with slope angles greater than 18°. The sedimentary infill sequence in the deep basins consists of about 75% turbidite-homogenite units (THU) and 25% hemiplagic sediments, deposited at sedimentation rates of 1 to 3 m/ka. Deposition of most of the THU has been triggered by seismo-tectonic activity that constitute a serious geohazard in the densely populated coastal areas. Identification and dating of the THUs are therefore important in the repeat-time determination of the earthquakes on different fault segments, and thus, for the probabilistic earthquake risk assessment in the region. We studied the sedimentological, physical and chemical characteristics of THUs in several cores recovered from different Marmara basins, and identified the record of the devastating (Mw=7.4) 1999 Izmit earthquake, using digital X-Ray Radiography, XRF Core Scanner, MSCL, stable isotope and grain-size analyses. The units were dated using AMS C-14 and radionuclide methods. THUs are characterized by a relatively thin (commonly mm to several cm thick) sand-silt unit at the base and thick (commonly several tens of cm) homogeneous mud at the top. Digital X-ray radiography indicates that the THUs have multiple sand-silt laminae in the basal unit showing bidirectional foresets and a sharp and often erosional basal contact. These features indicates deposition by a single turbidity current reflecting or deflecting from the opposite slopes. The XRF Core Scanner analysis indicates two specific geochemical anomalies associated with the turbiditites sampled over the active faults: Ca enrichment in the basal coarse part, and Mn

  7. Late Quaternary co-seismic sedimentation in the Sea of Marmara's deep basins

    NASA Astrophysics Data System (ADS)

    Beck, Christian; Mercier de Lépinay, Bernard; Schneider, Jean-Luc; Cremer, Michel; Çağatay, Namik; Wendenbaum, Evrard; Boutareaud, Sébastien; Ménot, Guillemette; Schmidt, Sabine; Weber, Olivier; Eris, Kadir; Armijo, Rolando; Meyer, Bertrand; Pondard, Nicolas; Gutscher, Marc-André; Turon, J.-L.; Labeyrie, L.; Cortijo, E.; Gallet, Y.; Bouquerel, Hélène; Gorur, N.; Gervais, A.; Castera, M.-H.; Londeix, L.; de Rességuier, A.; Jaouen, A.; Marmacore Cruise Party

    2007-07-01

    The deep, northern, part of the Sea of Marmara (northwestern Turkey) is composed of several aligned, actively subsiding, basins, which are the direct structural and morphological expression of the North-Anatolian Fault's northern branch. The last 20 kyr of their sedimentary fill (non-marine before 12 kyr BP) have been investigated through giant piston coring onboard R/V MARION-DUFRESNE (MARMACORE Cruise, 2001) and by chirp sub-bottom profiler onboard R/V ATALANTE during MARMARASCARPS Cruise (2002). Especially during the lacustrine stage, the infilling of the deep basins (Tekirdağ, Central, Kumburgaz, and Çinarcic Basins; up to 1250-m depth) was dominated by turbidites (with coarse mixed siliciclastic and bioclastic basal parts), intercalated in "hemipelagic-type" fine-grained calcareous and slightly siliceous clays. Often the turbidites show strong segregation and a sharp boundary between a coarse lower part and a suspended-load upper part. In the Central Basin, 8 m of a unique sedimentary event include a 5 to 8-m thick "homogenite" well imaged on seismic profiles. The latter is interpreted as related to a major - possibly earthquake-triggered - tsunami effect, as described in the Eastern Mediterranean by Kastens and Cita [Kastens K. and Cita M.B., 1981. Tsunami-induced sediment transport in the abyssal Mediterranean Sea. Geological Society of America Bulletin, 92:845-857]. In the marine (Holocene) upper part of the sedimentary fill, repeated to-and-from structures, affecting silt or fine sand, are evidencing seiche-like effects and, thus, earthquake triggering. Detailed correlations between two deep coring sites (at 1250 m and 1200 m) indicate more than 100% over-thickening in the deepest one; this implies specific processes of distribution of terrigenous input by dense currents (high kinetic energy, seiche effects, complex reflections on steep slopes). The peculiar sedimentary fill of the Sea of Marmara's Central Basin is interpreted as a direct consequence of

  8. The occurrence of pathogenic bacteria in some ships' ballast water incoming from various marine regions to the Sea of Marmara, Turkey.

    PubMed

    Altug, Gulsen; Gurun, Sevan; Cardak, Mine; Ciftci, Pelin S; Kalkan, Samet

    2012-10-01

    The composition and frequency of antibiotic resistance of pathogenic bacteria, the abundance of heterotrophic aerobic bacteria (HPC) and possible in-situ use of chromogenic agar were investigated in the ships' ballast water coming from different regions of the world to the Sea of Marmara, Turkey for the first time. The samples that were taken from 21 unit ships coming from various marine environments of the Southern China Sea, the Atlantic Ocean, the Mediterranean and the Black Sea to the Sea of Marmara, Turkey in 2009 and 2010 were tested. 38 bacteria species, 27 of them pathogenic bacteria belonging to 17 familia, were detected. Vibrio cholera was not detected in the samples. However, the presence of a high number of HPC, including a cocktail of pathogenic bacteria showed that the ships carry a potential risk for the Sea of Marmara.

  9. Development of a geodetic monitoring system using seafloor extensometers for the state of the submerged North Anatolian Fault in the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Kido, Motoyuki; Takahashi, Narumi; Yamamoto, Yojiro; Kalafat, Dogan; Pinar, Ali; Ozeren, Sinan; Ohta, Yusaku; Kaneda, Yoshiyuki

    2015-04-01

    Failure of the North Anatolian Fault (NAF) accompanied by a large earthquake is sequentially propagating to the west in Turley during the last century. However the region of the Marmara Sea, close to populous Istanbul, still remains unmoved and hence expected to have an impending devastating earthquake. In order to evaluate stress accumulation along the unmoved fault, which possibly controls the magnitude of the earthquake, it is crucial to know coupling ratio between the segments across the fault. The NAF is submerged beneath the Marmara Sea and inaccessible using onshore GNSS data. Therefore we have developed five seafloor extensometers and started their operation since September 2014 under SATREPS program between Japan and Turkey to directly measure the fault movement. The installation site is just on the Western High (~700m of depth), where strain partitioning is expected smaller (i.e., strain is concentrated at the main fault) because fewer sub-branches are observed. Four out of the five extensometers are alternately aligned across the fault in oblique direction with a baseline of roughly 1-km for each. The exact position of the fault is inferred from fine-scale bathymetric data based on multibeam surveys provided by Ifremer. The extensometers are designed that the main ranging data with associated information, such as temperature of sea water and etc., can be recovered through an acoustic modem at any time visiting the site without disruption of the measurement and is continuously worked at least 5 years with sampling rate of 12 hours. Based on the high-sampling (30 min.) preliminary data for 24 hours just after the installation, we found that the temporal variation of bottom temperature is quite stable due to strong density stratification in the Marmara Sea. Because of such stable condition, we confirmed that the system can potentially resolve 2-3 mm of shortening or extension along the 1-km-baseline. Maximum displacement across the fault is expected to be 2

  10. Tsunami Induced Sedimentation in Ports; A Case Study in Haydarpasa Harbor, Marmara Sea

    NASA Astrophysics Data System (ADS)

    Yalçıner, A. C.; Kian, R.; Velioglu, D.; Zaytsev, A.

    2015-12-01

    The movement of sea bottom or ground sediment material by tsunami cause erosion, deposition and hence bathymetry and topogrphy changes. The unexpected depth decrease at some parts of the enclosed basins and harbors may result in lack of movements of vessels. In order to understand the sediment movement inside the enclosed basins, Haydarpasa port in the sea of Marama is selected as a case study to understand the motion of tsunamis inside the port and identify their effects on harbor functions. The highest populated mega city Istanbul, located at north coast of the Sea of Marmara is one of the main centers of major economic activities in the region. In the study, the spatial and temporal changes of main tsunami parameters are investigated and their adverse effects on harbor performance are identified by analyzing the critical tsunami parameters (water elevation, current speed and momentum fluxes) in the port. Furthermore, the morphological changes due to tsunami induced flows are also considered. The morphological changes due to tsunamis can be governed by bathymetry and topography, tsunami current and the characteristics of ground material. Rouse number is one of the indicators to describe the initiation of sediment motion and transport modes under the flow. Therefore the morphological changes can be monitored by monitoring the change of the Rouse number. In this study the spatial and temporal change of Rouse number and hence modes of sediment transport in Haydarpasa port during a tsunami is investigated. Finally the functional loss of the port and the necessary strategies for reduction of tsunami impact and increase of resilience are also discussed. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 603839 (Project ASTARTE - Assessment, Strategy and Risk Reduction for Tsunamis in Europe)".

  11. Distribution of OCPs and PCBs in Mussels (Mytilus galloprovincialis) from the Marmara Sea Coastal Sites.

    PubMed

    Ulusoy, Şafak; Özden, Özkan; Päpke, Olaf

    2016-08-01

    Mussel samples were collected monthly between October-2010 and October-2011 from four stations (Bosphorus, Bandırma, Gelibolu, Tekirdağ) in the Marmara Sea. Two consecutive months' samples were homogenized and combined as a single group for analysis. Mussel samples were analyzed for Organochlorine pesticides (OCPs); (total-DDT, total-HCH, Endrin, α-Endosulfan, β-Endosulfan, Heptachlor) and Polychlorinated biphenyls (PCBs); (PCB 28, PCB 52, PCB 138, PCB 153, and PCB 180). All analyses were done according to Eurofins house method in ERGO Laboratory in Germany. Concentrations of α-endosulfan and heptachlor in mussel tissues were below method detection limits. The annual average OCPs concentrations among the stations ranged between 0.02 and 1.45 ng/g (wet weight), 1.9-99.75 ng/g (lipid weight) whereas the annual average PCBs concentrations among the stations ranged between 0.03 and 0.40 ng/g (wet weight), 1.71-26.48 ng/g (lipid weight), respectively. There was no relation between fat content of mussels and residues of the contaminants. PCB 138 and PCB 153 were the most predominant PCBs, while total-DDT and total-HCH were the most predominant OCPs in the mussels. Total-DDT concentrations were higher compared to total-HCH and PCBs isomers. Measured levels were below the national and international committees' and institutions' limits for human consumption and protection of aquatic biota.

  12. Preliminary Results of Full Seismic Waveform Tomography for Sea of Marmara Region (NW Turkey)

    NASA Astrophysics Data System (ADS)

    ÇUBUK, Y.; Fichtner, A.; Taymaz, T.

    2014-12-01

    The Marmara and Northwestern Anatolia regions are known to be a transition zone from the strike-slip tectonics to the extensional tectonics. Although, the Sea of Marmara has been subjected to several active and passive seismic investigations, the accurate knowledge on the heterogeneity in the crust and upper mantle beneath the study area still remains enigmatic. On small-scale tomography problems, seismograms strongly reflect the effects of heterogeneities and the scattering properties of the Earth. Thus, the knowledge of high-resolution seismic imaging with an improved 3D radially anisotropic crustal model of the Northwestern Anatolia will enable better localization of earthquakes, identification of faults as well as the improvement of the seismic hazard assessment. For this purpose, 3D non-linear full waveform inversion methodology has been used to obtain an accurate image of the lithosphere and the upper-most mantle structure over an area of 37.5˚-42˚ N and 25˚-32˚ E and down to a depth of 471 km. The earthquake data were principally obtained from the Kandilli Observatory and Earthquake Research Institute (KOERI) and Earthquake Research Center (AFAD-DAD) database. In addition to this, some of the seismic waveform data extracted from the Hellenic Unified Seismic Network (HUSN) stations that are located within our study region were also used in this study. We have selected and simulated the waveforms of earthquakes with magnitudes Mw ≥ 4 occurred in the period of 2007-2014. In total, 3002 three-component regional seismograms from 95 events were used. The initial 3D earth model for the study region has been implemented from the multi-scale seismic tomography study of Fichtner et al. (2013). The synthetic seismograms were computed with forward modeling of seismic wave propagation by using spectral elements method (SEM). The complete waveforms were filtered at 8-100 seconds. The adjoint method is used to compute sensitivity kernels. The differences between

  13. M≥7 Earthquake rupture forecast and time-dependent probability for the Sea of Marmara region, Turkey

    USGS Publications Warehouse

    Murru, Maura; Akinci, Aybige; Falcone, Guiseppe; Pucci, Stefano; Console, Rodolfo; Parsons, Thomas E.

    2016-01-01

    We forecast time-independent and time-dependent earthquake ruptures in the Marmara region of Turkey for the next 30 years using a new fault-segmentation model. We also augment time-dependent Brownian Passage Time (BPT) probability with static Coulomb stress changes (ΔCFF) from interacting faults. We calculate Mw > 6.5 probability from 26 individual fault sources in the Marmara region. We also consider a multisegment rupture model that allows higher-magnitude ruptures over some segments of the Northern branch of the North Anatolian Fault Zone (NNAF) beneath the Marmara Sea. A total of 10 different Mw=7.0 to Mw=8.0 multisegment ruptures are combined with the other regional faults at rates that balance the overall moment accumulation. We use Gaussian random distributions to treat parameter uncertainties (e.g., aperiodicity, maximum expected magnitude, slip rate, and consequently mean recurrence time) of the statistical distributions associated with each fault source. We then estimate uncertainties of the 30-year probability values for the next characteristic event obtained from three different models (Poisson, BPT, and BPT+ΔCFF) using a Monte Carlo procedure. The Gerede fault segment located at the eastern end of the Marmara region shows the highest 30-yr probability, with a Poisson value of 29%, and a time-dependent interaction probability of 48%. We find an aggregated 30-yr Poisson probability of M >7.3 earthquakes at Istanbul of 35%, which increases to 47% if time dependence and stress transfer are considered. We calculate a 2-fold probability gain (ratio time-dependent to time-independent) on the southern strands of the North Anatolian Fault Zone.

  14. The entrance of the Izmit Gulf : a key site for monitoring gas emissions and seismicity in the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Gasperini, Luca; Polonia, Alina; Favali, Paolo; Marinaro, Giuditta; Etiope, Giuseppe; Namık Ćaǧatay, M.; Henry, Pierre; Geli, Louis

    2010-05-01

    The Sea of Marmara has been widely recognized as a seismic gap that will be probably filled in the next decades by a large (M >=7) earthquake along the North Anatolian Fault (NAF) system. Accordingly, new research activities started in the last years, and the possibility of installing seafloor observatories, considered. Only long-term observatories allow continuous observation of large numbers of parameters. This capability is crucial for observing natural processes that are either very episodic, or statistically require long time series to be detected. Among these phenomena, gas seepage at the seabed, occurring in various locations in the Sea of Marmara (Geli et al., 2008) may be sensitive to seismicity, providing possible precursor signals. Several lines of evidence suggest that the Gulf of Izmit, in the eastern Sea of Marmara, is a key area for monitoring the activity of the NAF through seismometers and gas sensors, because: 1) it is an area characterized by a "focusing" of the NAF principal deformation zone into a single strike-slip fault, along which the dextral strike-slip rate averaged over geological times (10 mm/y) has been measured (Polonia et al., 2004); 2) it is close to the western end of the surface rupture associated with the 1999 Izmit earthquake; thus, it is a probable area where the next earthquake will nucleate; 3) it is characterized by gas and fluids emission related to the fault activity, as documented by acoustic images of the water-column and direct observations carried out using ROVs (Gasperini et al., 2009). The methane and hydrogen sulphide escape is also confirmed by the presence of "black patches" at the seafloor observed during MarNaut cruise. Seafloor multi-parameters monitoring in this area is therefore essential to unravel relationships between geochemical, physical and geophysical parameters and the mechanical behaviour of faults; the information could then be used for seismic risk assessments and to define early-warning strategies

  15. Sedimentary earthquake records in the İzmit Gulf, Sea of Marmara, Turkey

    NASA Astrophysics Data System (ADS)

    Çağatay, M. N.; Erel, L.; Bellucci, L. G.; Polonia, A.; Gasperini, L.; Eriş, K. K.; Sancar, Ü.; Biltekin, D.; Uçarkuş, G.; Ülgen, U. B.; Damcı, E.

    2012-12-01

    Sedimentary earthquake records of the last 2400 a, including that of the devastating 17 August 1999 İzmit earthquake (Mw = 7.4), were studied in cores from the 210 m-deep central Karamürsel Basin of the İzmit Gulf in the eastern Sea of Marmara, using laser grain-size, physical properties, stable O and C isotopes and XRF Core Scanner analyses, and dated by radionuclide and radiocarbon methods. The earthquake records are represented by turbidite-homogenite mass-flow units (THU) that commonly contain a basal coarse layer, a middle laminated silt layer and an overlying homogeneous mud layer. The coarse basal part has a sharp and sometimes scoured lower boundary, and includes multiple coarse (sand/silt) layers or laminae showing normal size grading. Multiple coarse layers and occasional bi-directional cross-bedding suggest deposition from a bed-load during water column oscillations, or seiche effect. The grain-size characteristics of the overlaying laminated silt and the homogeneous mud units indicate deposition from weak oscillating currents and homogeneous suspension, respectively. High Mn value just below the base of THUs suggests diagenetic enrichment at oxic/anoxic redox boundary before the mass-flow event. Sharp decrease in Mn with very low values within the THUs suggests transient redox conditions following the mass-flow. Variable geochemical compositions of the basal coarse layers indicate different sediment sources for different THUs. Eight sedimentary earthquake records observed in the last 2400 a in the İzmit Gulf can be confidently correlated with the historical earthquakes of 1999, 1509 AD (Ms = 7.2), 1296 AD (I = VII), 865 AD (I = VIII), 740 AD (I = VIII), 268 AD (I = VIII), 358 AD (I = IX), and 427 BC. This gives an earthquake recurrence time of ca. 300 a, with the interval between consecutive events ranging from 90 to 695 a.

  16. Distribution and sources of hydrocarbons in surface sediments of Gemlik Bay (Marmara Sea, Turkey).

    PubMed

    Unlü, Selma; Alpar, Bedri

    2006-07-01

    Seabottom sediments from Gemlik Bay, one of the most polluted spots in SW Marmara Sea, were analyzed for parent polycyclic aromatic hydrocarbons (PAHs) using gas chromatography-mass spectrometry. The concentration of 14 PAH compounds in sediment samples collected from 61 locations are distributed in a broad spectrum from low to very high concentration levels (50.8-13482 ng g-1). No significant correlation was found between summation operatorPAHs and organic carbon content while summation operatorPAHs increase slightly with silt/clay ratio. Therefore the distribution and concentrations of PAHs would be determined more by direct input, rather than by the type of sediment found locally. The most polluted areas are distributed nearshore eastern (Gemlik) and southern (Kursunlu, Mudanya and Trilye) coasts which are mainly influenced by rapid ecotourism development, direct discharges from rivers, surface run-off and drainage from port areas, domestic and industrial effluent discharges through outfalls and various contaminants from ships. Special PAH compound ratios, such as Phe/Anth, Flu/Py, B[a]A/Chry; LMWPAH/HMWPAH; Per/; Per/summation operatorPAH; Per/summation operator(penta-aromatics) and Flu/(Py+Flu), were calculated to evaluate different hydrocarbon origins and their relative importance. Pyrolytic activity is dominant along the highly-populated eastern and southern coasts. Meanwhile, petrogenic activity mixed with pyrolytic activity is a matter of fact in front of the main industrial-tourism ports and anchoring areas as well. Higher concentration of perylene are distributed along the mostly polluted eastern and southern coastal areas, however, the concentrations of perylene relative to the penta-aromatic isomers are dominant especially in the northern and deepest sectors of the bay, indicating diagenetic origin for the presence of perylene.

  17. Seasonal differences in the trace metal and macrominerals in shrimp (Parapenaus longirostris) from Marmara Sea.

    PubMed

    Ozden, Ozkan

    2010-03-01

    Seasonal changes in micromineral and macromineral concentrations in tissues of shrimp (Parapenaus longirostris) from Marmara Sea were measured for a 1-year period by using inductively coupled plasma mass spectrometer. The contents of investigated minerals in shrimp were found to be in the range of 0.374-0.716 mg/kg for Hg, 0.526-1.286 mg/kg for Se, 0.007-0.098 mg/kg for Cd, 0.197-0.230 mg/kg for Pb, 5.194-7.600 mg/kg for Cu, 11.090-17.707 mg/kg for Zn, 22.128-38.850 mg/kg for Al, 61.769-88.437 mg/kg for Fe, 0.262-0.368 mg/kg for As, 0.081-0.249 mg/kg for Co, 0.850-1.459 mg/kg for Mn, 0.316-0.507 mg/kg for Ni, 0.032-0.107 mg/kg for Sn, 1.262-1.502 mg/kg for Cr, 2,813.770-3,317.819 mg/kg for Na, 3,702.230-4,479.648 mg/kg for K, 495.782-650.280 mg/kg for Mg, 790.407-1,016.112 mg/kg for Ca, 2,685.873-3,657.658 mg/kg for P, and 0.454-0.942 mg/kg for I. The levels of Hg found in autumn were higher than maximum levels proposed by the European legislation.

  18. Chemical properties and fluorescence of DOM in relation to biodegradation in the interconnected Marmara-North Aegean Seas during August 2008

    NASA Astrophysics Data System (ADS)

    Zeri, C.; Beşiktepe, Ş.; Giannakourou, A.; Krasakopoulou, E.; Tzortziou, M.; Tsoliakos, D.; Pavlidou, A.; Mousdis, G.; Pitta, E.; Scoullos, M.; Papathanassiou, E.

    2014-07-01

    The dynamics of dissolved organic matter (DOM) in the Marmara Sea-Dardanelles Straits-North Aegean Sea were investigated using measurements of dissolved organic carbon and nitrogen (DOC, DON), PARAFAC modeling of 3-D excitation-emission fluorescence spectra and bacterial production (BP) and respiration (BR) rates. In the surface brackish waters, chemical parameters showed an increase from the Aegean to the Marmara (DOC: 65-217 μmol L- 1; DON: 3.08-9.34 μmol L- 1; Dissolved Inorganic Nitrogen (DIN): 0.044-1.38), followed by an increase in BP rates (7.2-195 nmol L- 1 d- 1). In the subsurface waters, DIN also showed an increase in the Marmara basin (0.085-9.79 μmol L- 1) followed by an increase in BP rates (3.3-17.4 nmol L- 1 d- 1). PARAFAC modeling revealed three fluorescent components: λex/λem: < 260(330)/464 nm, humic-like; λex/λem: <(260) 285/364 nm, quinone-like; λex/λem: 270/308 nm, tyrosine-like. DOC:DON ratios were found similar for the Marmara (21 ± 3) and the N. Aegean Sea (19 ± 2). The slopes ΔDOC:ΔDON suggested that in the Marmara Sea mineralization processes require more carbon relative to nitrogen (22.3), whereas in the N. Aegean there is preferential removal of nitrogen over carbon (5.66). The lack of significant correlation between DOC and AOU (apparent oxygen utilization) in the deep Marmara waters indicates that particulate organic matter is important in deep mineralization processes.

  19. Sedimentological and geochemical properties of a tsunami deposit in a lagoon north of Sea of Marmara, Turkey

    NASA Astrophysics Data System (ADS)

    Altinok, Y.; Alpar, B.; Cagatay, M. N.; Akcer, S.; Unlu, S.; Balkis, N.; Ozer, N.; Aykurt, H.

    2009-04-01

    The coasts of the Sea of Marmara have been hit by numerous tsunami waves in the past, which might have surged up along its northern coastal strip and invaded inland more than 2 km. In order to understand and determine the tsunami potential and their possible effects along these coasts, detailed studies are needed on the past earthquake- and landslide-related tsunamis whose effects are presently unknown. These studies include gathering appropriate historical data, mapping out the underwater topography in detail, determining the active faults and underwater landslides and modeling. Marine geophysical works and numerical wave modeling applications show that three near surface faults out of six main structural elements outlined in the Sea of Marmara may trigger tsunami waves which may be effective along the northern coast. These are the west boundary fault of east Marmara ridge, the northern boundary fault of the middle Marmara ridge and the segment of Kumburgaz-Gaziköy. Ground motions on these fault segments may cause important wave runups along the coasts of Buyukcekmece and Kucukcekmece lagoons in the north with 2.5 to 4.5 m high waves depending on their source mechanism. Another indispensable study is to trace paleo-tsunami deposits in low-energy depositional environments such as coastal wetlands and places protected from the sea by sand barriers. The coasts of the Sea of Marmara, however, have been under rapid urbanization during last 50 years and only a very few areas preserve original coastal sediment successions. Meanwhile lagoons may also be important depositional areas for tsunami deposits and protect them from post-depositional erosion. The Kucukcekmece lagoon, which is separated from the sea by a narrow strip of sandbar (300-350 m), was investigated in the present study. A piston core (TKÇ-5) was recovered in the southern part. It is 463 cm long and composed by fine sediments, from clay to silt, with some distinctive thin coarse grained layers. An

  20. Some population parameters of Ruditapes philippinarum (Bivalvia, Veneridae) on the southern coast of the Marmara Sea, Turkey

    NASA Astrophysics Data System (ADS)

    Çolakoğlu, Serhat; Palaz, Mustafa

    2014-12-01

    Ruditapes philippinarum, a venerid clam, is a dominant species in the sandy and muddy areas in the coastal waters of the Marmara Sea. Intensive commercial harvesting of this species is conducted in these regions. We studied the population dynamics of R. philippinarum on the southern coast of the Marmara Sea (Bandırma). Samples were collected on a monthly basis between September 2012 and August 2013. Seasonal von Bertalanffy growth parameters using the length-frequency distribution of R. philippinarum were estimated at L ∞ = 67.50 mm and K = 0.33 year-1, and the seasonal oscillation in growth rate was 0.53. The slowest growth period was in January. The growth performance index and potential lifespan were 3.182 and 8.06 years, respectively. The growth relationship was confirmed to have a positive allometric pattern. The average total mortality rate was estimated to be 0.777 year-1, whereas the natural and fishing mortality rates were 0.539 and 0.238 year-1, respectively. The current exploitation rate of R. philippinarum was 0.306. The recruitment pattern peaked during June-August, and spawning occurred between May and August. The results of this study provide valuable information on the status of R. philippinarum stocks.

  1. Seafloor Geodetic Monitoring of the North Anatolian Fault in the Sea of Marmara: System Installation and its Initial Result

    NASA Astrophysics Data System (ADS)

    Kido, M.

    2015-12-01

    The North Anatolian Fault (NAF) get across the mainland of Turkey is known as a quite active strike slip fault. The earthquake recurrence period for individual segment is estimated roughly 300 years based on historical records. The Marmara Segment is the major seismic gap since the last earthquake in 1766, while the Murefte earthquake occurred in 1912 at its west side and the Izmit earthquake in 1999 at its east side. The relative motion across the NAF is ~22 mm/yr based on the data from space geodesy. Investigating how much degree of this displacement is released by aseismic creep or accumulated by slip deficit in the Marmara Segment is crucial to know the total seismic risk in this region. Because the NAF is submerged in the Sea of Marmara and is inaccessible by space geodesy, we employed seafloor geodetic technique using extensometers, which acoustically monitor baseline length across a strain-localized zone, such as surface trace of a fault. In 2014, we installed five extensometers at the Western High crossing the NAF one after the other, where the surface trace of the NAF is prominent and gas emission from the seafloor is reported in. Totally four beselines of ~1 km range are successfully formed and quality of initial test data was promising. Based on the initial data, detectable level of the baseline change is estimated to be ~2mm, which owing to quite stable seawater near the bottom due to strong density stratification in the Sea of Marmara. The extensometers are designed that data can be recovered via acoustic modem without disrupt the monitoring. Since the installation, we have visited the site twice and have recovered the data for ten months in total. Temperature measured by thermistor equipped on each extensometer showed coherent change and gradual increase by 0.007 degree during the period. This reflects apparent beseline shortening due to the corresponding increase of the sound speed. In the preliminary temperature correction, difference of the change

  2. Late Glacial to Holocene evolution and sea-level history of Gulf of Gemlik, Sea of Marmara, Turkey

    NASA Astrophysics Data System (ADS)

    Sabuncu, Asen; Kadir Eriş, K.; Kaslilar, Ayse; Namık Çaǧatay, M.; Gasperini, Luca; Filikçi, Betül

    2016-04-01

    The Gulf of Gemlik is an E-W elongated trans-tensional basin with a maximum depth of 113 m, located on the middle strand of the North Anatolian Fault (NAF) in the south eastern part of the Sea of Marmara (SoM). While during the Holocene the sea level in the Gulf of Gemlik changed in tandem with the water level changes in the SoM, it may have been different in the late glacial when the Sea of Marmara was lacustrine. Beside the tectonic activity related to the NAFZ, eustatic sea level changes would have controlled the basin evolution and consequent sedimentary history during the different paleocanographic phases of the SoM. Considering the limited studies on the late glacial-Holocene stratigraph of the Gulf of Gemlik, this study aims to investigate the depositional units and their environments with respect to different allogenic and autogenic controls. For these purposes, we analyzed over 300 2 - 7 kHz bandwidth high-resolution gridded seismic sub-bottom CHIRP profiles together with 70 kHz high resolution multibeam bathymetry with backscatter data. Four seismic stratigraphic units were defined and correlated with chronstratigraphic units in five piston cores covering the last 15.8 ka BP according to radiocarbon ages (14C). The depth-scale accuracy of chronostratigraphic units in cores is of key importance for the precise calculation of sedimentation rates. Correlation between the seismic profiles and cores were made by matching Multi-Sensor Core-Logger (MSCL) data and seismic reflection coefficients and amplitudes for different stratigraphic units. The impedance data derived from the logger were used to generate a synthetic seismogram. We used an approach to display, estimate, and correct the depth-scale discrepancies due to oversampling affecting the upper part of sedimentary series during piston coring. The method is based on the resynchronization of synthetic seismograms computed from high-quality physical property logs to the corresponding CHIRP profiles. Each

  3. Pore fluid chemistry of the North Anatolian Fault Zone in the Sea of Marmara: A diversity of sources and processes

    NASA Astrophysics Data System (ADS)

    Tryon, M. D.; Henry, P.; ćAǧAtay, M. N.; Zitter, T. A. C.; GéLi, L.; Gasperini, L.; Burnard, P.; Bourlange, S.; Grall, C.

    2010-10-01

    As part of the 2007 Marnaut cruise in the Sea of Marmara, an investigation of the pore fluid chemistry of sites along the Main Marmara Fault zone was conducted. The goal was to define the spatial relationship between active faults and fluid outlets and to determine the sources and evolution of the fluids. Sites included basin bounding transtensional faults and strike-slip faults cutting through the topographic highs. The basin pore fluids are dominated by simple mixing of bottom water with a brackish, low-density Pleistocene Lake Marmara end-member that is advecting buoyantly and/or diffusing from a relatively shallow depth. This mix is overprinted by shallow redox reactions and carbonate precipitation. The ridge sites are more complex with evidence for deep-sourced fluids including thermogenic gas and evidence for both silicate and carbonate diagenetic processes. One site on the Western High displayed two mound structures that appear to be chemoherms atop a deep-seated fluid conduit. The fluids being expelled are brines of up to twice seawater salinity with an exotic fluid chemistry extremely high in Li, Sr, and Ba. Oil globules were observed both at the surface and in cores, and type II gas hydrates of thermogenic origin were recovered. Hydrate formation near the seafloor contributes to increase brine concentration but cannot explain their chemical composition, which appears to be influenced by diagenetic reactions at temperatures of 75°C-150°C. Hence, a potential source for fluids at this site is the water associated with the reservoir from which the gas and oil is seeping, which has been shown to be related to the Thrace Basin hydrocarbon system. Our work shows that submerged continental transform plate boundaries can be hydrologically active and exhibit a diversity of sources and processes.

  4. Spatio-temporal variations of soil radon patterns around the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Passarelli, Luigi; Seyis, Cemil; Woith, Heiko

    2016-04-01

    Typically, the noble gas radon displays cyclic daily (S1), semidiurnal (S2) as well as seasonal variations in geological environments like soil air, groundwater, rock, caves, and tunnels. But there are also cases where theses cycles are absent. We present examples from a radon monitoring network of 21 sites around the Sea of Marmara. The works were carried out in the frame of MARsite, a project related to the EU supersite initiative (MARsite has received funding from the European Union's Seventh Programme for research, technological development and demonstration under grant agreement No 308417). Alpha-meters from the Canadian company alpha-nuclear are used to measure the radon concentration in counts per 15 minutes at a depth of 80 cm. The long-term average radon concentrations at 21 sites vary between 35 and 1,000 counts per 15 minutes. Typical seasonal variations are absent at more than 6 sites. Sites with seasonal variations have radon minima usually during winter (December to April), radon maxima during summer months (June to October). We carefully investigated radon time series for all the monitoring stations. We find that at some sites the empirical distribution of radon counts is clearly bimodal and in other bimodality is absent. In those stations we analysed the time series in different time intervals in order to highlight seasonal periodicity in the radon emission. The empirical distributions obtained by time-windowing of the radon signals results to be statistically different one another after applying a Kolmogorov-Smirnov test at significance level of 0.1. Usually the maxima in radon emission occur in summer time but, interestingly enough, two sites are characterized by radon maxima in winter periods. We further investigate the radon signals seeking for smaller scale periodicity. We calculated Fourier spectra of all 21 sites. Daily cycles are absent at 6 sites which is an unusual phenomenon. Daily cycles may disappear, if the local system is heavily

  5. Late Pleistocene to Holocene paleoceanographic and paleo-climatic changes in Gulf of Gemlik, Sea of Marmara, Turkey

    NASA Astrophysics Data System (ADS)

    Filikci, Betül; Kadir Eriş, K.; Namık Çaǧatay, M.; Gasperini, Luca; Sabuncu, Asen; Acar, Dursun; Yalamaz, Burak

    2016-04-01

    Gulf of Gemlik is an east-west oriented marine inlet with a maximum depth of 113 m in the south-eastern part of the Sea of Marmara. It is located on the middle branch of the North Anatolian Fault Zone. While the Gulf of Gemlik is separated from the SoM by a bedrock sill at -50 m, there were presumably several disconnections during the Late Pleistocene to Holocene, but the timing of the youngest connection around the onset of the Holocene is still controversial. Here, we attempt to elucidate the paleoceanographic and paleoenvironmental changes during the late glacial-Holocene using the multi-proxy analysis of a core extending back to 13 ka BP. The multi-proxy data include physical and geochemical properties together with AMS 14C ages. The core sediments covering the time period of the last 13 ka BP consists of two main lithostratigraphic units. The lower Unit L2 represents the lacustrine phase of the gulf prior to 10.6 ka BP, while the upper Unit L1 is an overlying transgressive mud drape deposited during the main part of the Holocene. Unit L2 deposited prior 10.6 ka BP represents Bølling-Allerød and Younger Dryas climatic periods, when prograding shelf edge sediments were deposited in the form of well sorted medium sands with brackish water bivalve shells (Dreissenapolymorpha). At the beginning of the Holocene, the rising sea level in the Sea of Marmara breached the -50 m sill at 10.6 ka BP, and therefore the Gulf of Gemlik was converted into a marine realm. Soon after, the water stratifications allowed to the formation of the previously studied two sapropels in the gulf, as shown by increased TOC contents. μ-XRF Ca/Ti and Sr/Ca profiles of Unit L1 provide evidence of rapid climatic changes at 8.2 ka BP and 4.2 ka BP, representing cold and dry short climatic periods which are well correlated with previous marine and lake studies in İznik Lake south of the Sea of Marmara. Keywords: Gemlik Gulf, core, paleoclimate, Late Pleistocene to Holocene

  6. Physics-based Broadband Ground Motion Simulations for Probable M>7.0 earthquakes in the Marmara Sea Region (Turkey)

    NASA Astrophysics Data System (ADS)

    Akinci, Aybige; Aochi, Hideo; Herrero, Andre; Pischiutta, Marta; Karanikas, Dimitris

    2016-04-01

    The city of Istanbul is characterized by one of the highest levels of seismic risk in Europe and the Mediterranean region. The important source of the increased risk in Istanbul is the remarkable probability of the occurrence of a large earthquake, which stands at about 65% during the coming years due to the existing seismic gap and the post-1999 earthquake stress transfer at the western portion of the North Anatolian Fault Zone (NAFZ). In this study, we have simulated hybrid broadband time histories from two selected scenario earthquakes having magnitude M>7.0 in the Marmara Sea within 10-20 km of Istanbul believed to have generated devastating 1509 event in the region. The physics-based rupture scenarios, which may be an indication of potential future events, are adopted to estimate the ground motion characteristics and its variability in the region. Two simulation techniques (a full 3D wave propagation method to generate low-frequency seismograms, <~1 Hz and a stochastic technique to simulate high-frequency seismograms, >1Hz) are used to compute more realistic time series associated with scenario earthquakes having magnitudes Mw >7.0 in the Marmara Sea Region. A dynamic rupture is generated and computed with a boundary integral equation method and the propagation in the medium is realized through a finite difference approach (Aochi and Ulrich, 2015). The high frequency radiation is computed using stochastic finite-fault model approach based on a dynamic corner frequency (Motazedian and Atkinson, 2005; Boore, 2009). The results from the two simulation techniques are then merged by performing a weighted summation at intermediate frequencies to calculate broadband synthetic time series. The hybrid broadband ground motions computed with the proposed approach are validated by comparing peak ground acceleration (PGA), peak ground velocity (PGV), and spectral acceleration (SA) with recently proposed ground motion prediction equations (GMPE) in the region. Our

  7. Elastic and inelastic Coulomb stress changes around the mega-city of Istanbul and the Marmara Sea

    NASA Astrophysics Data System (ADS)

    Lorenzo-Martin, F.; Wang, R.; Pohl, D.; Roth, F.

    2006-12-01

    During the last century, a sequence of strong earthquakes ruptured the North Anatolian Fault in a clear westward migration, with the Mw = 7.4 Izmit and the Mw = 7.1 Düzce earthquakes in 1999 as the most recent and westernmost events. If this sense of propagation continues, a strong shock west of the Izmit- Düzce rupture can be expected. This region would be the Marmara Sea, just south of Istanbul, a mega-city with 12 million inhabitants. A strong earthquake in the region would therefore have catastrophic consequences, both in loss of life and monetary costs. Deformation models often assume purely elastic behaviour for the crust and upper mantle, and therefore the crust instantaneously responds to the motion on the rupture. When using the elastic approach, any time dependency of the deformation might be attributed to time-dependent fault slip. However, such an approach neglects the effect of time dependent deformation processes like after-slip, poroelastic rebound, or viscoelastic relaxation, which have been shown to be not negligible. On the other hand, the influence of these post- seismic, time-dependent deformation processes is still a matter of discussion, as it is which process has the most important role after a strong earthquake. In this work, we considered the historical seismicity and recent information on the faults around the city of Istanbul and the Marmara Sea to study the current state and evolution of the Coulomb stress field in the region. We show the effect of previous earthquakes on the regional Coulomb stress field, as well as its development in time due to different post seismic deformation processes. This information might be useful for seismic hazard assessment in the region. Also, we simulate the effect that a potential realistic strong event in the Marmara Sea would have on the Coulomb stress field, as well as its evolution in time immediately after the event. These calculations can be important for the assessment of aftershock hazard after

  8. Heavy metal concentrations and the variations of foraminifers in the Silivri-Kumbagi area (NW Marmara Sea, Turkey)

    NASA Astrophysics Data System (ADS)

    Ünal Yümün, Zeki; Murat Kılıç, Ali; Önce, Melike

    2016-04-01

    In the area between Silivri (İstanbul) and Kumbagi (Tekirdag), NW of Marmara Sea, there is a considerable extent in marine pollution from industrial and settlements wastes, sea transports, and agricultural activities. The most important one of these pollutions is the spread of heavy metals. Our research investigated sediments in order to determine whether heavy minerals affected biota such as recent foraminifers, or not. Our investigation area starts from Marmara Ereglisi, in the east, continues to Tekirdag and Kumbagi, in the west. 10 sea-water samples, 10 sediment-core samples and one 10 m core-drilling sample, taken 250 m off-shore from coast line. As a result of this sampling geochemical analysis of the bottom-mud and water samples were done and the ratio of heavy metals and other contaminants determined. For heavy metal analyses, concentration analysis of 12 heavy metals (Cd, Fe, Cu, Pb, Zn, Al, Co, Cr, Mn, Ni, As, and Hg) has been conducted, as ppm, in sediment samples taken from the levels in which foraminifers are collected. Perpendicular (spatial) heavy metal concentration changes have been determined with off-shore drilling samples and horizontal changes (geochronological) have been determined with the help of core samples. Especially, it has been understood that heavy metal concentrations in recent sediments are higher compared to the past. In this research the samples have been taken from each 10 cm. of core and drilling samples to collect the benthic foraminifers. In this context, 15 grams of dry sediment sample taken from each level, have been washed in 125 μm sieves in order to determine its benthic foraminifer content. Benthic foraminifera from these samples have been identified taxonomically and their morphological differentiation has been determined after taking SEM photos. As a result of this study, the foraminifera types of "Adelosinacliarensis, Adelosinamediteranensis, Adelosinapulchella, Ammonia compacta, Ammonia parkinsonia, Ammonia tepida

  9. Improving the study of the seismicity in the western and central parts of the Sea of Marmara using Ocean Bottom Seismometers

    NASA Astrophysics Data System (ADS)

    Cros, Estelle; Géli, Louis; Bayrakci, Gaye; Cagatay, Namik; Gürbüz, Cemil

    2013-04-01

    The Marmara Sea is located between the Agean Sea and the Black Sea, along the North Anatolian strike-slip fault, which experienced a sixty year sequence of earthquakes since 1940. Prior to this sequence, which ended with the Izmit and Duzce earthquakes in 1999, at the eastern end of the Sea of Marmara (SoM), the fault ruptured to the west in 1912 in Ganos, with an estimated moment magnitude of 7.4. Therefore, a major earthquake is expected within the SoM seismic gap. In order to better understand the seismicity and to reduce the threshold of detection, a network of ten OBS with four components was deployed by Ifremer with R/V Yunus of Istanbul Technical University, in the western and central parts of the Marmara Sea to record the micro-seismicity from the immediate vicinity of the main Marmara Fault, between April and August, 2011. The network was specifically designed to survey the segments crossing the Western High, where gas hydrates where recently found, the Central Basin and the Kumburgaz Basin. During this period more than one hundred earthquakes were detected by the EMSC (European-Mediterranean Seismological Centre) in the Sea of Marmara. Because the basins of the Sea of Marmara are filled with more than 5 km of Plio- Quaternary soft ("slow") sediments, it is of critical importance to take into account the velocity structure of the offshore domain, which is drastically different from the one onshore, and the bathymetry. To improve the localization of seismic events, a 3D velocity model was thus considered and implemented in the Sytmis software developed by INERIS. This model is based on the tomographic data collected in 2001 using a controlled source experiment and on the numerous multichannel seismic profiles that provide information on, respectively, the deeper structures and the upper, sedimentary layers. Preliminary results are presented. Special focus will be given on the clustering of the micro-seismicity in the Western High and on a swarm event. As a

  10. Late Glacial to Holocene Sealevel changes in the Sea of Marmara; evidence from high-resolution seismic and core studies

    NASA Astrophysics Data System (ADS)

    Eris, K. K.

    2009-04-01

    Late Glacial to Holocene sedimentary record of the northern shelf of the Sea of Marmara (SoM) is documented by detailed stratigraphic analysis of sub-bottom (Chirp) profiles and sediment cores. The reflection profiles reveal the presence of four seismic stratigraphic units S4-S1 that are equivalent to lithostratigraphic units L4-L1, separated from each other by shelf-crossing unconformities of Q1 to Q3. The seismic profiles from the SoM entrance to the Strait of İstanbul (SoI) allow us to divide the Holocene sediments of Unit S1 into seven sub-units, therefore, we can estimate high-frequency sealevel fluctuations. The SoM was converted into freshwater lake in the beginning of the marine isotope stage 3 (MIS-3) due to global sealevel fall below the Dardanelles outlet (-83 m). During the MIS-3 and main part of the MIS-2, disconnection with the Mediterranean Sea and the forced regression in the SoM gave rise to deposition of progradational units (seismic units S4 and S3) as sediment wedges thickening towards the shelf edge. The maximum lowstand of the ‘Marmara lake' is associated with river incisions below to 105 m water depth, above which a prominent erosional surface formed on the shelf. In contrast to the LGM disconnection with the Mediterranean Sea, the SoM experienced a period of Black Sea outflow between 15-13.5 14C ka BP, when the Black Sea level rised above the sill depth (-35 m) of the SoI. This gave rise to a freshwater transgression in the lake leading to rise the water level to -85 m by 13 ka BP. Following the reconnection with the Mediterranean Sea at 12 ka BP, the Younger Dryas (YD) cold period in the SoM was associated by a Black Sea outflow at 11.5 ka BP leading to formation of a levee within the axis of the paleo Bosphorus shelf valley. During the YD, the sealevel increase was interrupted by stillstands at -76 m and -71 m. In the seismic profiles from the SoM entrance to the SoI, the colonization of algal-serpulid bioherms across the reflector

  11. Investigaton of ÇINARCIK Basin and North Anatolian Fault Within the Sea of Marmara with Multichannel Seismic Reflection Data

    NASA Astrophysics Data System (ADS)

    Atgın, O.; Çifçi, G.; Sorlien, C.; Seeber, L.; Steckler, M.; Sillington, D.; Kurt, H.; Dondurur, D.; Okay, S.; Gürçay, S.; Sarıtaş, H.; Küçük, H. M.

    2012-04-01

    The Sea of Marmara is becoming a natural laboratory for structure, sedimentation, and fluid flow within the North Anatolian fault (NAF) system. Much marine geological and geophysical data has been collected there since the deadly 1999 M=7.2. Izmit earthquake. The Sea of Marmara occupies 3 major basins, with the study area located in the eastern Cinarcik basin near Istanbul. These basins are the results of an extensional component in releasing segments between bends in this right-lateral tranmsform. It is controversial whether the extensional component is taken up by partitioned normal slip on separate faults, or instead by oblique right-normal slip on the non-vertical main northern branch of the NAF. High resolution multichannel seismic reflection (MCS) and multibeam bathymetry data collected by R/V K.Piri Reis and R/V Le-Suroit as part of two different projects respectively entitled "SeisMarmara", "TAMAM" and "ESONET". 3000 km of multichannel seismic reflection profiles were collected in 2008 and 2010 using 72, 111, and 240 channels of streamer with a 6.25 m group interval. The generator-injector airgun was fired every 12.5 or 18.75 m and the resulting MCS data has 10-230 Hz frequency band. The aim of the study is to investigate continuation of North Anatolian Fault along the Sea of Marmara, in order to investigate migration of depo-centers past a fault bend. We also test and extend a recently-published age model, quantify extension across short normal faults, and investigate whether a major surface fault exists along the southern edge of Çınarcık Basin. MCS profiles indicate that main NAF strand is located at the northern boundary of Çınarcık Basin and has a large vertical component of slip. The geometry of the eastern (Tuzla) bend and estimated right-lateral slip rates from GPS data requires as much of ten mm/yr of extension across Çınarcık Basin. Based on the published age model, we calculate about 2 mm/yr of extension on short normal faults in the

  12. Physically based probabilistic seismic hazard analysis using broadband ground motion simulation: a case study for the Prince Islands Fault, Marmara Sea

    NASA Astrophysics Data System (ADS)

    Mert, Aydin; Fahjan, Yasin M.; Hutchings, Lawrence J.; Pınar, Ali

    2016-08-01

    The main motivation for this study was the impending occurrence of a catastrophic earthquake along the Prince Island Fault (PIF) in the Marmara Sea and the disaster risk around the Marmara region, especially in Istanbul. This study provides the results of a physically based probabilistic seismic hazard analysis (PSHA) methodology, using broadband strong ground motion simulations, for sites within the Marmara region, Turkey, that may be vulnerable to possible large earthquakes throughout the PIF segments in the Marmara Sea. The methodology is called physically based because it depends on the physical processes of earthquake rupture and wave propagation to simulate earthquake ground motion time histories. We included the effects of all considerable-magnitude earthquakes. To generate the high-frequency (0.5-20 Hz) part of the broadband earthquake simulation, real, small-magnitude earthquakes recorded by a local seismic array were used as empirical Green's functions. For the frequencies below 0.5 Hz, the simulations were obtained by using synthetic Green's functions, which are synthetic seismograms calculated by an explicit 2D /3D elastic finite difference wave propagation routine. By using a range of rupture scenarios for all considerable-magnitude earthquakes throughout the PIF segments, we produced a hazard calculation for frequencies of 0.1-20 Hz. The physically based PSHA used here followed the same procedure as conventional PSHA, except that conventional PSHA utilizes point sources or a series of point sources to represent earthquakes, and this approach utilizes the full rupture of earthquakes along faults. Furthermore, conventional PSHA predicts ground motion parameters by using empirical attenuation relationships, whereas this approach calculates synthetic seismograms for all magnitudes of earthquakes to obtain ground motion parameters. PSHA results were produced for 2, 10, and 50 % hazards for all sites studied in the Marmara region.

  13. Activity on the multi-stranded Central Branch of the North Anatolian Fault along the southern shelf of the Marmara Sea, Turkey

    NASA Astrophysics Data System (ADS)

    Okay, S.; Sorlien, C. C.; Cifci, G.; Cormier, M. H.; Dondurur, D.; Steckler, M. S.; Barin, B.; Seeber, L.

    2014-12-01

    The North Anatolian Fault (NAF), a major continental transform boundary, splays westward into three branches in the Sea of Marmara region of NW Turkey. The main northern branch passes only ~20 km from Istanbul and has been the subject of intense investigation, The central branch enters the sea of Marmara in Gemlik Bay and extends westeward along the southern shelf of the Sea of Marmara. However, its detailed offshore geometry as well as its level of seismic activity have remained controversial. Under the SoMAR Project, two geophysical cruises were carried out in 2013 and 2014 to map the major sedimentary basins and shallow fault patterns of the southern shelf of the Marmara Sea. Including our 2008 and 2010 acquisition, we acquired 4,430 km of high-resolution multichannel seismic, sparker, multibeam bathymetric and CHIRP data. We used the new data to correlate our published late Quaternary stratigraphic age model across the outer shelf, and a ~1/4 Ma horizon across the Inner Shelf, thus providing a chronology that can be applied to the tectonic history of the central branch. As it exits Gemlik Bay, the central branch itself diverges westward into strands in a fan pattern. A half dozen southern strands strike WSW and W, with one continuing onland near the Kocasu River delta between Bandırma and Mudanya, and others dying out offshore. The northern strand strikes WNW and splays again into the İmrali Ridge Fault and the Imrali Fault across respectively the mid-shelf and the shelf break. A middle fault, the Kapidag fault, is present between Kapidag Peninsula and Marmara Island. Most of the faults increase their vertical component with depth, suggesting activity during Pliocene through Holocene time. The Kapidag fault and Imrali Ridge fault each exhibit between 1 and 2 km of vertical separation of acoustic basement. Late Quaternary rates of vertical separation on these faults can accumulate the total vertical component after Miocene time. Thus, steady-state activity is

  14. Collaborative Research: The North Anatolian Fault System in the Marmara Sea, Turkey - Insights from the Quaternary evolution of a multi-stranded transform

    NASA Astrophysics Data System (ADS)

    Okay, Seda; Sorlien, Christopher; Cifci, Gunay; Cormier, Marie-Helene; Dondurur, Derman; Steckler, Michael; Barin, Burcu; Seeber, Leonardo; Gungor, Talip; Meriç İlkimen, Elif; Becel, Anne

    2015-04-01

    The North Anatolian Fault (NAF), a major continental transform boundary, splays westward into three branches in the Sea of Marmara region of NW Turkey. The main northern branch passes only ~20 km from Istanbul and has been the subject of intense investigation, The central branch enters the sea of Marmara in Gemlik Bay and extends westward along the southern shelf of the Sea of Marmara. However, its detailed offshore geometry as well as its level of seismic activity have remained controversial. Under the SoMAR, bilateral TUBITAK-NSF Project, two geophysical cruises were carried out in 2013 and 2014 to map the major sedimentary basins and shallow fault patterns of the southern shelf of the Marmara Sea. Including our 2008 and 2010 acquisition, we acquired 4,430 km of high-resolution multichannel seismic, sparker, multibeam bathymetric and CHIRP data. We used the new data to correlate our published late Quaternary stratigraphic age model across the outer shelf, and a ~1/4 Ma horizon across the Inner Shelf, thus providing a chronology that can be applied to the tectonic history of the central branch. As it exits Gemlik Bay, the central branch itself diverges westward into strands in a fan pattern. A half dozen southern strands strike WSW and W, with one continuing onland near the Kocasu River delta between Bandırma and Mudanya, and others dying out offshore. The northern strand strikes WNW and splays again into the İmrali Ridge Fault and the Imrali Fault across respectively the mid-shelf and the shelf break. A middle fault, the Kapidag fault, is present between Kapidag Peninsula and Marmara Island. Most of the faults increase their vertical component with depth, suggesting activity during Pliocene through Holocene time. The Kapidag fault and Imrali Ridge fault each exhibit between 1 and 2 km of vertical separation of acoustic basement. Late Quaternary rates of vertical separation on these faults can accumulate the total vertical component after Miocene time. Thus

  15. Effects of neotectonic and sedimentary processes on the seafloor geomorphology of the Tekirdag Basin of the western Marmara Sea (Turkey)

    NASA Astrophysics Data System (ADS)

    Ergin, Mustafa; Yigit-Faridfathi, Füsun

    2010-05-01

    This study forms part of a project (TUBITAK YDABCAG 101Y071) with the main purpose of investigation of late Quaternary slope stability, sediment mass movements and turbidite formations in the tectonically active Tekirdag Basin and its margins from the western Marmara Sea. The results were also intended to relate to the major earthquakes and sea-level changes. During this project, in 2001 aboard the former R/V MTA Sismik-1, a total of 100 km seismic reflection profiles were obtained along three tracklines representing from shelf to slope to deep basin environments. A multichannel airgun seismic system and well-known methods and principles of seismic stratigraphy was used for interpretations. At 11 sites from 29 to 1111 m water depths gravity sediment cores were taken having 100 to 359 cm recoveries and textural and structural characteristics were determined using standard petrographic methods. The NEE-SWW directed seismic profile (TKD-01) which runs parallel to the North Anatolian Fault zone displayed syntectonic sedimentation with negative flower structure that increased in thickness toward the Ganos Fault and pinched out in the east. ENE section of this profile also bears structures of underwater landslides with slump facies. Seismic profile TKD-02 which crosses the Tekirdag Basin in WNW-ESE direction most likely displays major 3 fault segments of the NAF zone. Many faults and syntectonic sedimentation structure can be recognized on this profile. A morphological feature of a sediment wedge or former lowstand delta at the present shelf edge can be related to the effects of last sea-level change. Mounded and chaotic seismic reflection configurations which indicate channel and slope-front fill as well as slump facies are thought to reflect submarine slides and slumps. Other morphological features such as incised submarine valleys or channels running E-W direction are also present on this profile. The seismic profile (TKD-03) runs from NNW to SSE across the basin and

  16. A review and assessment of gas hydrate potential in Çınarcık Basin, Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Sile, Hande; Akin, Cansu; Ucarkus, Gulsen; Namik Cagatay, M.

    2016-04-01

    The Sea of Marmara (NW Turkey), an intracontinental sea between the Mediterranean and Black Seas, is located in a tectonically active region with the formation of shallow gas hydrates and free gas. It is widely known that, Sea of Marmara sediments are organic-rich and conducive to production of methane, which is released on the sea floor through active fault segments of the North Anatolian Fault (Geli et al., 2008). Here we study the gas hydrate potential of the Çınarcık Basin using published data and our core analyses together with gas hydrate stability relations. The gas sampled in the Çınarcık Basin is composed mainly of biogenic methane and trace amounts of heavier hydrocarbons (Bourry et al., 2009). The seafloor at 1273 m depth on the Çınarcık Basin with temperature of 14.5oC and hydrostatic pressure of 127.3 atm corresponds to the physical limit for gas hydrate formation with respect to phase behavior of gas hydrates in marine sediments (Ménot and Bard, 2010). In order to calculate the base of the gas hydrate stability zone in Çınarcık Basin, we plotted T (oC) calculated considering the geothermal gradient versus P (atm) on the phase boundary diagram. Below the seafloor, in addition to hydrostatic pressure (10 Mpa/km), we calculated lithostatic pressure due to sediment thickness considering the MSCL gamma ray density values (~1.7 gr/cm3). Our estimations show that, gas hydrate could be stable in the upper ~20 m of sedimentary succession in Çınarcık Basin. The amount of gas hydrate in the Çınarcık Basin can be determined using the basinal area below 1220 m depth (483 km2) and average thickness of the gas hydrate stability zone (20 m) and the sediment gas hydrate saturation (1.2 % used as Milkov, 2004 suggested). The calculations indicate the potential volume of gas hydrate in Çınarcık Basin as ~11.6x107 m3. Such estimates are helpful for the consideration of gas hydrates as a new energy resource, for assessment of geohazards or their

  17. Sedimentation rates in the Sea of Marmara: a comparison of results based on organic carbon—primary productivity and 210Pb dating

    NASA Astrophysics Data System (ADS)

    Ergi˙n, Mustafa; Bodur, Mehmet N.; Yildi˙z, Mehmet; Edi˙ger, Di˙lek; Edi˙ger, Vedat; Yemeniciog˛lu, S.; Yücesoy, Fulya

    1994-10-01

    A large number of surficial sediment samples (75 grab samples, one boomerang core, four ☐ cores) as well as primary productivity measurements have been used to estimate the rates of sediment accumulation in the Sea of Marmara; using an empirical expression for the relationship between surface productivity and organic carbon content of the sediment ( MüLLER-SUESS formula). It was found that calculated low sedimentation rates occurred on the inner southern Marmara shelf (ave. 8 cm 1000 y -1) where the primary production was relatively high (ave. 161 gC m -2 y -1); and vice versa, high sedimentation rates were calculated for the southwestern shelf (123 cm 1000 y -1), an area with very low primary productivity (64 gCm -2 y -1). This discrepancy among the values, is probably due to the combined effects of the distinctive and peculiar oceanography of the Sea of Marmara (well stratified flow, strong horizontal transport, and varying conditions for mineralization of organic matter etc.). Utilizing the 210Pb method, sediment accumulation rates have been determined of approximately 190 cm 1000 y -1 on the northeastern shelf, 120 cm 1000 y -1 in the eastern depression, 260 cm 1000 y -1 in the central depression, 100 cm 1000 y -1 in the western depression and 280 cm 1000 y -1 on the southwestern shelf of this sea. These generally high rates of sedimentation using this method further support the conclusion that the amount of primary produced organic carbon preserved in the recent bottom deposits of the Sea of Marmara seems not to be universally related to the rate of sedimentation.

  18. Distribution and environmental impacts of heavy metals and radioactivity in sediment and seawater samples of the Marmara Sea.

    PubMed

    Otansev, Pelin; Taşkın, Halim; Başsarı, Asiye; Varinlioğlu, Ahmet

    2016-07-01

    In this study, the natural and anthropogenic radioactivity levels in the sediment samples collected from the Marmara Sea in Turkey were determined. The average activity concentrations (range) of (226)Ra, (238)U, (232)Th, (40)K and (137)Cs were found to be 23.8 (13.8-34.2) Bq kg(-1), 18.8 (6.4-25.9) Bq kg(-1), 23.02 (6.3-31.1) Bq kg(-1), 558.6 (378.8-693.6) Bq kg(-1) and 9.14 (4.8-16.3) Bq kg(-1), respectively. Our results showed that the average activity concentrations of (226)Ra, (238)U and (232)Th in the sediment samples were within the acceptable limits; whereas the average activity concentration of (40)K in the sediment samples was higher than the worldwide average concentration. The average radium equivalent activity, the average absorbed dose rate and the average external hazard index were calculated as 100.01 Bq kg(-1), 48.32 nGy h(-1) and 0.27, respectively. The average gross alpha and beta activity in the seawater samples were found to be 0.042 Bq L(-1) and 13.402 Bq L(-1), respectively. The gross alpha and beta activity concentrations increased with water depth in the same stations. The average heavy metal concentrations (range) in the sediment samples were 114.6 (21.6-201.7) μg g(-1) for Cr, 568.2 (190.8-1625.1) μg g(-1) for Mn, 39.3 (4.9-83.4) μg g(-1) for Cu, 85.5 (11.0-171.8) μg g(-1) for Zn, 32.9 (9.1-73.1) μg g(-1) for Pb and 49.1 (6.8-103.0) μg g(-1) for Ni. S5 station was heavily polluted by Cr, Cu, Ni and Pb. The results showed that heavy metal enrichment in sediments of the Marmara Sea was widespread.

  19. Widespread gas emissions in the Sea of Marmara in relation with the tectonic and sedimentary environments: Results from shipborne multibeam echosounder water column imagery (MARMESONET expedition, 2009)

    NASA Astrophysics Data System (ADS)

    Dupré, Stéphanie; Scalabrin, Carla; Géli, Louis; Henry, Pierre; Grall, Céline; Tary, Jean-Baptiste; Ćaǧatay, Namık.; Imren, Caner

    2010-05-01

    Acoustic systems in marine geosciences are mainly used to explore the seabed and image sub-bottom sedimentary units. However, side-scan sonars and echosounders can detect gas emissions from the seabed into the water column. Recently, advances in technology and computer processing allow carrying out large-scale 3D surveys of the entire water column with multibeam systems, so far dedicated to seabed imagery. A shipborne multibeam survey of the water column in the Sea of Marmara was performed with the R/V Le Suroit during the MARMESONET expedition (4-25 November 2009), that is part of the ESONET (European Seas Observatory NETwork) demonstration mission MarmaraDM. Data were acquired with a Simrad EM302 multibeam echosounder (27-33 kHz, 288 beams, 1°x2°, 2 or 5 ms pulse length) with automatic swath width control and equidistant sounding pattern over water depths varying from 300 to 1300 m. Volume backscattering coefficients were stored with <10 m depth bins along more than 2000 nm acoustic tracks. Gas bubble echoes were very well detected by the EM302 system within the water depth range of the Sea of Marmara, mostly with the central beams but also with the outer beams for the flares with strong backscatter intensity and large imprint. Geo-referenced gas flare 3D visualization is performed with Movies3D software developed for fish school echo description and biomass assessment (Trenkel et al., 2009). The distribution of water column acoustic echoes in the Sea of Marmara reveals that free gas emissions from the seabed are more widespread than expected from previous studies using ROVs, submersibles as well as acoustic methods (Géli et al., 2008; Zitter et al., 2008). Numerous acoustic gas flares were detected in association with the North Anatolian fault system and some appear to be localized on known active fault traces. However, gas emissions also spread around the edges of the sedimentary basins (e.g. Cinarcik and Tekirdag basins) and on structural highs (e

  20. High Resolution Multichannel Imaging of Basin Growth Along a Continental Transform: The Marmara Sea Along the North Anatolian Fault in NW Turkey

    NASA Astrophysics Data System (ADS)

    Steckler, M. S.; Çifçi, G.; Demirbağ, E.; Akhun, S. D.; Büyükaşik, E.; Cevatoglu, M.; Coşkun, S.; Diebold, J.; Dondurur, D.; Gürçay, S.; Imren, C.; Kücük, H. M.; Kurt, H.; Özer, P. G.; Perinçek, E.; Seeber, L.; Shillington, D.; Sorlien, C.; Timur, D.

    2008-12-01

    The 1500-km-long North Anatolian continental transform (NAF) accommodates the westward motion of the Anatolian platelet relative to Asia. The Marmara Trough in western Turkey is a large composite Quaternary structure that includes three main extensional basins with water depths reaching ~1200m separated by shallower ridges. Syntectonic sedimentation in the basins with highly variable sea-level-related changes in accumulation rates provide valuable time-space markers for reconstructing structural growth and basin development in the Marmara Sea. The TAMAM (Turkish-American MArmara Multichannel) Project is a collaboration between several US and Turkish research institutes. During July 2008, TAMAM collected ~2700 km of multichannel profiles in the Marmara Sea using the R/V K. Piri Reis. MCS data were sampled with a 1-ms interval on the first 72 channels with 6.25m group spacing in a 600m streamer. The source was a 45/45 cu. in. GI air gun, which was fired every 12.5 or18.75m. The gun-streamer offset was 40 or 100 m depending on water depth. Both the gun and streamer were towed at a depth of 3 or 4m. This configuration yielded high-resolution images of the stratigraphy in the Marmara Sea. TAMAM follows a recent series of impressive seismotectonic studies of the NAF in the Marmara Sea area. Previous seismic cruises focused on deep penetration MCS imaging of the overall basin structure and faulting or very high-resolution imaging of the near-surface faulting. TAMAM fills a gap in resolution imaging the stratigraphy that records the history of deformation in the basins and linkages between faults. We will present preliminary high-resolution images of the stratigraphy and tectonics beneath the Marmara Sea highlighting the following exciting observations and initial results from this experiment: 1) Improved stratigraphic correlations between the major basins, a primary goal of the experiment; 2) Clearer imaging of active faults, including the NAF, the less studied southern

  1. Seismicity along the Main Marmara Fault, Turkey: from space-time distribution to repeating events

    NASA Astrophysics Data System (ADS)

    Schmittbuhl, Jean; Karabulut, Hayrullah; Lengliné, Olivier; Bouchon, Michel

    2016-04-01

    The North Anatolian Fault (NAF) poses a significant hazard for the large cities surrounding the Marmara Sea region particularly the megalopolis of Istanbul. Indeed, the NAF is presently hosting a long unruptured segment below the Sea of Marmara. This seismic gap is approximately 150 km long and corresponds to the Main Marmara Fault (MMF). The seismicity along the Main Marmara Fault (MMF) below the Marmara Sea is analyzed here during the 2007-2012 period to provide insights on the recent evolution of this important regional seismic gap. High precision locations show that seismicity is strongly varying along strike and depth providing fine details of the fault behavior that are inaccessible from geodetic inversions. The activity strongly clusters at the regions of transition between basins. The Central basin shows significant seismicity located below the shallow locking depth inferred from GPS measurements. Its b-value is low and the average seismic slip is high. Interestingly we found also several long term repeating earthquakes in this domain. Using a template matching technique, we evidenced two new families of repeaters: a first family that typically belongs to aftershock sequences and a second family of long lasting repeaters with a multi-month recurrence period. All observations are consistent with a deep creep of this segment. On the contrary, the Kumburgaz basin at the center of the fault shows sparse seismicity with the hallmarks of a locked segment. In the eastern Marmara Sea, the seismicity distribution along the Princes Island segment in the Cinarcik basin, is consistent with the geodetic locking depth of 10km and a low contribution to the regional seismic energy release. The assessment of the locked segment areas provide an estimate of the magnitude of the main forthcoming event to be about 7.3 assuming that the rupture will not enter significantly within creeping domains.

  2. The Late Quaternary Seismic Stratigraphy of the Southern Shelf of the Strait of Istanbul (Sea of Marmara, Turkey)

    NASA Astrophysics Data System (ADS)

    Deniz Abuş, Eren

    2013-04-01

    The sea level changes in the northern shelf (Istanbul) of the Sea of Marmara and the sources of sedimentary packages at the southern exist of the Strait of Istanbul have been an ongoing debate the past decade. This study aims to enlighten both the sea level oscillations since ~125 ky before present and the structure of aforesaid sedimentary sequence, Unit 2, near Kurbaǧalı River observed in high resolution sparker seismic sections using global sea level change curves. Contary to Hiscott et al. (2002), Gökaşan et al. (2005), and Eriş et al. (2007) preferring the global sea level change curve in Fairbanks (1989) so as to explain the age interval of the sequence, we introduced the curve in Bard et al. (1990) presented the 230Th - 234U ages of Acropora palmata samples collected from the offshore of the island of Barbados, where Fairbanks (1989) submits the first chronology using the limited 14C ages. Therefore, the deposition of the Unit 2 was considered as 10 - 9 ky before present by Hiscott et al. (2002), as 12 - 11±1.1 ky BP by Gökaşan et al. (2005), and as 6.4 - 3.2 ky BP by Eriş et al. (2007). Having applied this calibration to our study, the age interval of the Unit 2 was calculated as 11.5 ky before present. In previous studies, Unit 2 was presented as prograding deltaic deposits of the Kurbaǧalı River yet our studies illustrates that the stream current of Kurbaǧalı River is not capable of supporting adequate sediment input, which is about 1.5 x 8.5 kilometers when the thickness and rate of propagation of Unit 2 are considered. Thanks to high resolution seismic sections and bathymetry, we firstly introduce that the Unit 2 is a point-bar structure forming as a product of the meandering regime at the southern exit of the Bosphorus.

  3. Geochemical and isotopic features of geothermal fluids around the Sea of Marmara, NW Turkey

    NASA Astrophysics Data System (ADS)

    Italiano, Francesco; Woith, Heiko; Seyis, Cemil; Pizzino, Luca; Sciarra, Alessandra

    2016-04-01

    Earthquake processes provoke modifications of the crust affecting the fluid regime with changes in water level in wells, in temperature and/or chemical composition of groundwaters, in the flow-rate of gas discharges and in their chemical and isotopic composition. In the frame of MARsite (MARsite has received funding from the European Union's Seventh Programme for research, technological development and demonstration under grant agreement No 308417) the relationship between fluids and seismogenesis has been approached collecting geochemical data of local significance and evaluating them in geochemical interpretative models of fluids circulation and interactions as well as defining their behaviour over a seismic-prone area. During three fluid sampling campaigns in 2013, 2014, and 2015 a suite of 120 gas samples were collected from 72 thermal and mineral water springs/wells in the wider Marmara region along the Northern and Southern branches of the North Anatolian Fault Zone (NAFZ). Bubbling gases were collected if available, in all other cases the gas phase was extracted from water samples collected on that purpose. Gas samples were analyzed for the main chemical composition as well as their isotopic composition (He and C). The results highlight that the vented gases are a binary mixture of two end-members having nitrogen and carbon dioxide as main components. The geochemical features of the gas phase are the result of several processes that have modified their pristine composition. Atmospheric and deep-originated volatiles mix at variable extents and interact with cold and hot groundwaters. CO2 is normally the main gas species. But it's concentration may decrease due to gas-water interactions (GWI) increasing the relative concentration of N2 and other less soluble gases. A high CO2 content indicates minor interactions. Thus, the easier and faster the pathways are from the deep layers toward the Earth's surface, the lower are the interactions. The volatiles keep

  4. Reply to Discussion: a critique of Possible waterways between the Marmara Sea and the Black Sea in the late Quaternary: evidence from ostracod and foraminifer assemblages in lakes İznik and Sapanca, Turkey, Geo-Marine Letters, 2011

    NASA Astrophysics Data System (ADS)

    Nazik, Atike; Meriç, Engin; Avşar, Niyazi

    2012-06-01

    In their discussion of our 2011 paper dealing with possible waterways between the Marmara Sea and the Black Sea in the "late" Quaternary, based on data from ostracod and foraminifer assemblages in lakes İznik and Sapanca, Turkey, Yaltırak et al. (Geo-Mar Lett 32:267-274, 2012) essentially reject the idea of any links whatsoever, be they between the Marmara Sea and the lakes İznik and Sapanca, or further to the Black Sea via the valley of the Sakarya River. The evidence they provide in support of their view, however, is essentially circumstantial, in part conjectural, and also inconclusive considering the findings in favour of linkage between the Marmara Sea and the lakes at the very least, while the proposed connection with the Sakarya River valley remains speculative because of the lack of unambiguous data. On the other hand, Yaltırak et al. (Geo-Mar Lett 32:267-274, 2012) do raise valid points of concern which deserve careful future investigation, the most important being the possibility of sample contamination from dumped marine sediment used for construction purposes along some parts of the shore of Lake İznik. We agree that a concerted multidisciplinary effort is required to address the many unresolved issues in connection with the potential waterways proposed by us and others before us.

  5. Temporal evolution of anthropogenic pollution and environmental changes in a marine inlet: the example of Gemlik Gulf, Marmara Sea

    NASA Astrophysics Data System (ADS)

    Albut, Gülüm; Namık Cagatay, M.; Gungor, Nurdan; Gungor, Emin; Acar, Dursun; Balkıs, Nuray

    2014-05-01

    Marginal marine basins are particularly prone to anthropogenic pollution because of restricted water circulation and commonly high population density in their drainage basin. Gemlik Gulf is such a semi-enclosed inlet with maximum depth of 113 m in the eastern part of the Sea of Marmara, which is separated from the rest of the Marmara shelf by a -50 m deep sill. It is under anthropogenic risk from different industrial and municipal pollution sources in its drainage basin. Moreover, Gemlik Gulf, located on the middle branch of the North Anatolian fault (NAF), is under a future earthquake risk with a high possibility of pollution from disruption to industrial plants and municipal infrastucture, similar to the the one that occurred in the Ä°zmit Gulf during the 1999 Mw 7.4 Ä°zmit earthquake. In this study, we investigated the extent and temporal evolution of the heavy metal and organic pollution using a wide range of analyses of a 84 cm sediment/water interface long core from the central part of the basin, involving μ-XRF Core Scanner, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), Total Organic (TOC) and Inorganic Carbon (TIC), and mass spectrometric stable C and N isotopic and C and N elemental analyses. The chronology of the core was determined using radionuclide (210Pb and 137Cs) and AMS radiocarbon analysis. The core covers about last 800 years. The upper part of the core, representing the last 155 years, is gray mud grading into very dark grey mud in the top 84 cm. The 5-8 cm interval below sea floor (bsf) (AD 1985-1995) includes 3 white laminae consisting of coccolithophore Emiliania huxleyi and another carbonate rich layer deposited during AD 1855-1950. TOC values are commonly between 1.5 and 2.5 % below 12.5 cmbsf (AD 1965), but increases up to 4.25 % towards the core top. The core includes a mass flow unit, which is most probably triggered by the AD 1855 earthquake, and is characterized by high contents of Fe, Zr, low contents of Ca, Nb, La U, Th

  6. Solearhynchus kostylewi (Meyer, 1932) comb. nov. (acanthocephala: Echinorhynchidae), a rare parasite of Solea solea (pisces: soleidae) in the Gemlik Bay, Sea of Marmara.

    PubMed

    Kvach, Y; Oğuz, M C

    2010-03-01

    Paracanthocephaloides kostylewi (Meyer, 1932), a rare parasite of the common sole Solea solea, previously placed in the Arhythmacanthidae, is transfered to the genus Solearhynchus de Buron & Maillard, 1985 of the family Echinorhynchidae as Solearhynchus kostylewi (Meyer, 1932) new comb., because its proboscis is armed by a single type of hooks, the posterior hook in each row is pinlike and with feebly developed root. The species is redescribed on the basis of newly collected material from the Gemlik Bay, Sea of Marmara. A key to the species of Solearhynchus is provided.

  7. Assessment of tsunami resilience of Haydarpaşa Port in the Sea of Marmara by high-resolution numerical modeling

    NASA Astrophysics Data System (ADS)

    Aytore, Betul; Yalciner, Ahmet Cevdet; Zaytsev, Andrey; Cankaya, Zeynep Ceren; Suzen, Mehmet Lütfi

    2016-08-01

    Turkey is highly prone to earthquakes because of active fault zones in the region. The Marmara region located at the western extension of the North Anatolian Fault Zone (NAFZ) is one of the most tectonically active zones in Turkey. Numerous catastrophic events such as earthquakes or earthquake/landslide-induced tsunamis have occurred in the Marmara Sea basin. According to studies on the past tsunami records, the Marmara coasts have been hit by 35 different tsunami events in the last 2000 years. The recent occurrences of catastrophic tsunamis in the world's oceans have also raised awareness about tsunamis that might take place around the Marmara coasts. Similarly, comprehensive studies on tsunamis, such as preparation of tsunami databases, tsunami hazard analysis and assessments, risk evaluations for the potential tsunami-prone regions, and establishing warning systems have accelerated. However, a complete tsunami inundation analysis in high resolution will provide a better understanding of the effects of tsunamis on a specific critical structure located in the Marmara Sea. Ports are one of those critical structures that are susceptible to marine disasters. Resilience of ports and harbors against tsunamis are essential for proper, efficient, and successful rescue operations to reduce loss of life and property. Considering this, high-resolution simulations have been carried out in the Marmara Sea by focusing on Haydarpaşa Port of the megacity Istanbul. In the first stage of simulations, the most critical tsunami sources possibly effective for Haydarpaşa Port were inputted, and the computed tsunami parameters at the port were compared to determine the most critical tsunami scenario. In the second stage of simulations, the nested domains from 90 m gird size to 10 m grid size (in the port region) were used, and the most critical tsunami scenario was modeled. In the third stage of simulations, the topography of the port and its regions were used in the two nested

  8. Marine-to-lacustrine transition, mud volcanism, and slope instability in an active tectonic setting: the MIS 5 to 4 transition in the Sea of Marmara, Turkey

    NASA Astrophysics Data System (ADS)

    Grall, Céline; Henry, Pierre; Kendé, Julia; Namık Çaǧatay, M.; Kadir Eriş, K.; Paillès, Christine; Sorlien, Christopher; Shillington, Donna; McHugh, Cecilia; Steckler, Michael; Çifçi, Günay; Géli, Louis

    2016-04-01

    In the Sea of Marmara, glacio-eustatic cycles set the tempo of a complex history of disconnection and reconnection with the Black Sea and with the global ocean through the Mediterranean Sea. As a result, the sedimentary record consists of alternating high stand marine sediments and lowstand sea or lake sediments. The Sea of Marmara is also an active transtensional basin along the Northern branch of the North Anatolian Fault (NNAF), which accommodates most (~3/4) of the 21-27 mm/a dextral slip between Eurasia and Anatolia. This peculiar setting makes the Sea of Marmara an exceptional site to study the interplay of paleo-environmental factors and seismotectonic processes. Notably, Mass Transport Deposits (MTDs) crossing the faults provide offset markers although their age remains uncertain. A high resolution seismic stratigraphic model has been proposed for 100 ka glacial cycles, based on onlap sequences within basins, and paleo-deltas at shorelines. The sedimentation rate in basins decreases during episodes of sea-level rise and reach maximum values during low stands. Remarkably, seismic reflector sequences display nearly identical character for locations with similar sedimentation rate. The uppermost sequence boundary reflector (Red-H1) has been recently cored at several locations during MARSITECRUISE (Ifremer R/V Pourquoi Pas?, Oct-Nov. 2014), enabled us to correlate high resolution seismic data with core data. The Red-H1 reflector is regionally characterized by a high amplitude and a reverse polarity. Correlations between seismic data and piston core logs indicate that the reverse polarity of this reflector may be explained by a negative density contrast between lacustrine sediments above and a greenish sapropellic layer of several meters thickness below. On shelves, Red-H1 is on top of the low stand wedge. On slopes and topographic highs, Red-H1 appears as an erosional surface laterally correlative with an onlapping unit in basins and is frequently overlain by

  9. Submarine slides, slumps and turbidites in relation to various tectonic and sedimentary processes in the Çinarcik Basin of the eastern Marmara Sea (Turkey)

    NASA Astrophysics Data System (ADS)

    Ergin, Mustafa; Sakitas, Alper; Sarikavak, Kerim; Keskin, Seref

    2013-04-01

    The main purpose of this study was to determine and understand the impacts of the climatic changes, active tectonism, slope instability and sediment mass movements in the eastern Marmara Sea (Turkey) during the Holocene. Of these, sea level changes, earth quakes, slides, slumps and turbidites were considered to be the major causes to shape the seafloor in the region. With this in mind and within a framework of a larger Project (TÜBİTAK-YDABAG 101Y071), after the major earthquake of 17 August 1999 in Kocaeli-Turkey, both sediment samples and seismic reflection profiles were obtained during the August 2000 Cruise of the Research Vessel "MTA "SİSMİK 1" at water depths between 58 and 1249 meters in the Çınarcık Basin of the eastern Marmara Sea (NW Turkey). Offshore studies covered shelf, slope and basin-floor subenvironments. Onboard, airgun and multichannel seismic reflection system was used along 7 tracklines aligned to N-S and E-W directions. At 15 sites gravity cores were deployed and from 53 to 367 cm thick core sediments were obtained. Grain size analysis, visual core descriptions, and conventional radicarbon datings were also made. To interpret seismic profiles, well-known seismic facies analysis and stratigraphic methods were applied. Fine-grained and grayish-green colored siliciclastic mud was the dominant sediment type (also called "homogenite") deposited on the floor. The coarser-grained intervals and laminations would likely suggest effects of not only turbidites from active tectonism but they can also be related to the wind-driven offshore storm deposits and river floods after heavy rain-falls. Active normal faults on the shelves, fault scarps along the slopes and negative flower structure of syntectonic sedimentation in the deep basin floor observed on the seismic profiles all must indicate the consequences of westerly extension of the North Anatolian Fault Zone in the Marmara Sea. Seismic profiles displayed sediment structures of underwater

  10. Physically-Based Ground Motion Prediction and Validation A Case Study: Mid-sized Marmara Sea Earthquakes

    NASA Astrophysics Data System (ADS)

    Mert, A.

    2015-12-01

    In this study we have two main purposes. The first one is to simulate five midsize earthquakes (Mw≈5.0) recorded in the Marmara region, which has a geologically complex and heterogeneous crustal structure. We synthesize ground motion for the full wave train on three components, and applied a 'physics based' solution of earthquake rupture. The simulation methodology is based on the studies by Hutchings et al. (2007), Scognamiglio and Hutchings (2009). For each earthquake, we synthesized seismograms using by 500 different rupture scenarios that were generated by Monte Carlo selection of parameters within the range. Synthetic ground motion is a major challenge for seismic hazard assessment studies. Especially after the adoption of performance-based design approach with the Earthquake resistant design of engineering structures. To compute realistic time histories for different locations around Marmara region can be helpful for engineering design, retrofitting the existing structures, hazard and risk management studies and developing new seismic codes and standards.The second purpose is to validate synthetic seismograms with real seismograms. We follow the methodology presented by Anderson (2003) for validation. This methodology proposes a similarity score based on averages of the quality of fit measuring ground motion characteristics and uses a suite of measurements. Namely, the synthetics are compared to real data by ten representative ground motion criteria. The applicability of Empirical Green's functions methodology and physics based solution of earthquake rupture had been assessed in terms of modeling in complex geologic structure. Because the methodology produces source and site specific synthetic ground motion time histories and goodness-of-fit scores of obtained synthetics is between 'fair' to 'good' range based on Anderson's score, we concluded that it can be tried to produce ground motion that has not previously been recorded during catastrophic earthquake

  11. Seismarmara 2001: A Marine Seismic Survey and Offshore-onshore Artificial Source and Natural Earthquakes In The Seismogenic Region of The Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Hirn, A.; Singh, S.; Charvis, P.; Géli, L.; Laigle, M.; Lépine, J.-C.; de Voogd, B.; Saatcilar, R.; Taymaz, T.; Ozalaybey, S.; Shimamura, H.; Selvi, O.; Karabulut, H.; Murai, Y.; Nishimura, Y.; Yamada, A.; Vigner, A.; Bazin, S.; Tan, O.; Yolsal, S.; Aktar, M.; Galvé, A.; Sapin, M.; Marthelot, J.-M.; Imren, C.; Ergin, M.; Tapirdamaz, C.; Koçaoglu, A.; Tarancioglu, A.; Diaz, J.; Verhille, J.; Auffret, Y.; Cetin, S.; Oçakoglu, N.; Karakoç, F.; Klien, E.; Ricolleau, A.; Selvigen, V.; Demirbag, E.; Hakyemez, Y.; Sarikawak, K.

    SEISMARMARA is a Turkish-French survey carried out in July-October 2001 as a multi-method approach of seismic structure and activity of the Sea of Marmara. This is the segment of the North Anatolian Fault system that continues the one that produced the two destructive earthquakes in 1999 to the East, and is prone to future major earth- quakes as it has experienced in the past. Aims of the programme are to shed light on the regional tectonics and recent evolution at crustal scale, image faults by their structure and seismic activity, and provide a model and reference to improve loca- tion of earthquakes and focal mechanism studies. The programme bases on marine multichannel reflection seismics (MCS), ocean bottom seismometers (OBS) and land stations recording of wide-angle reflection-refraction from the same source, as well as recording of local earthquakes for tomography and stress/strain distribution. The French N/O Le Nadir acquired 4000 km of MCS profiles in the northern Sea of Mar- mara, using a 4.5 km long digital streamer with 360-channels and sources of 8100 cu. in., or 2900 cu. in., provided by a 12-airgun array in single-bubble mode. Navigation safety was provided by a vessel of the Turkish Coast Guards (Sahil Güvenlik), Leg 1 comprises 4 E-W lines and 30 cross-lines in the whole Marmara Trough, leg 2 has 1 been devoted to a very dense grid of lines in the Cinarcik basin and its margins, record- ing over 80 dip-lines at 0.6-0.9 km spacing At sea-bottom 38 OBS, with 3-component sensors and continuous recording over 1 to 2-month in order to also record natural earthquakes were deployed and collected by the Turkish ship MTA Sismik-1. On land the permanent array has been complemented by as many temporary stations, in par- ticular over 30 continuous recording 3-component 2 Hz stations. Refraction seismics from offshore to onshore was further implemented by short-duration deployments of vertical component lightweight instruments with short recording capacity. A

  12. Constructing a 3D structural block diagram of the Central Basin in Marmara Sea by means of bathymetric and seismic data

    NASA Astrophysics Data System (ADS)

    Demirbağ, Emin; Kurt, Hülya; Düşünür, Doğa; Sarıkavak, Kerim; Çetin, Suna

    2007-12-01

    In this study we made a comparative interpretation of multibeam bathymetric and seismic reflection data with different resolutions and penetration properties collected in the Central Basin of the Marmara Sea. Our main objectives were (i) to investigate and compare the active tectonic deformation observed on the sea bottom and within the uppermost sedimentary layers to that of the deep-seated deformation within the limits of resolution and penetration of the available geophysical data and (ii) to build a three-dimensional (3D) block diagram of the active tectonic and buried features by means of a sliced mapping technique. In this approach, we produced slice maps of the active and buried structural features at selected depths and then combined them to form a 3D structural block diagram. Motivation for our work was to produce a 3D structural diagram to derive a more detailed image of the structural features in the Central Basin where there is no available 3D seismic data. The observations from the bathymetry and seismic data and developed 3D diagram support the presence of a through-going strike-slip fault that forms a rotational depression zone against a right-stepping strike-slip faulting causing a pull-apart basin in the Central Depression zone.

  13. Seismicity distribution and locking depth along the Main Marmara Fault, Turkey

    NASA Astrophysics Data System (ADS)

    Schmittbuhl, J.; Karabulut, H.; Lengliné, O.; Bouchon, M.

    2016-03-01

    The seismicity along the Main Marmara Fault (MMF) below the Marmara Sea is analyzed during the 2007-2012 period to provide insights on the recent evolution of this important regional seismic gap. High precision locations show that seismicity is strongly varying along strike and depth providing fine details of the fault behavior that are inaccessible from geodetic observations. The activity strongly clusters at the regions of transition between basins. The Central basin shows significant seismicity located below the shallow locking depth inferred from GPS measurements. Its b-value is low and the average seismic slip is high. All observations are consistent with a deep creep of this segment. On the contrary, the Kumburgaz basin at the center of the fault shows sparse seismicity with the hallmarks of a locked segment. In the eastern Marmara Sea, the seismicity distribution along the Princes Island segment in the Cinarcik basin, is consistent with the geodetic locking depth of 10 km and a low contribution to the regional seismic energy release. The assessment of the locked segment areas provide an estimate of the magnitude of the main forthcoming event to be about 7.3 assuming that the rupture will not enter significantly within creeping domains.

  14. MARSite: Marmara as a Supersite

    NASA Astrophysics Data System (ADS)

    Meral Ozel, N.; Necmioglu, O.; Ergintav, S.; Ozel, A.; Erdik, M. O.

    2013-12-01

    The Marmara Region is one of the most active seismic regions in Turkey and also most densely populated and fast-developing part in the country. The region was effected with destructive earthquakes in its past, and the seismic hazard in Marmara Region has become a great concern especially after the Izmit and Duzce earthquakes in 1999 costing 18.000 people lives. Recent studies indicate that the region has a great potential to produce M≥7.0 earthquake within the next 30 years. Hence, a realistic assessment of the earthquake hazard in this area including Istanbul with more then 15 million inhabitants is a priority. MARsite project identifes the Marmara region as a ';Supersite' to aggregate on-shore, off-shore and space-based observations, comprehensive geophysical monitoring, improved hazard and risk assessments encompassed in an integrated set of activities. MARsite Consortium constitutes of 18 European research institutions with a long record of scientific history and success, and 3 SMEs, from 7 nations of the Euro-Mediterranean area. MARsite aims to harmonize geological, geophysical, geodetic and geochemical observations to provide a better view of the post-seismic deformation of the 1999 Izmit earthquake (in addition to the post-seismic signature of previous earthquakes), loading of submarine and inland active fault segments and transient pre-earthquake signals, related to stress loading with different tectonic properties in and around Marmara Sea. These studies are planned to contribute to high-quality rapid source-mechanism solutions and slip models, early warning and rapid-response studies. The project outputs will also be adapted to improve various phases of the risk management cycle with the creation of a link between the scientific community and end users. In this context, MARsite will develop novel geo-hazard monitoring instruments including high-resolution displacement meters, novel borehole instrumentation and sea-bottom gas emission and heat

  15. A first deep seismic survey in the Sea of Marmara: Deep basins and whole crust architecture and evolution

    NASA Astrophysics Data System (ADS)

    Laigle, Mireille; Becel, Anne; de Voogd, Béatrice; Hirn, Alfred; Taymaz, Tuncay; Ozalaybey, Serdar; Members Of Seismarmara Leg1 Team

    2008-06-01

    Increased source strength, streamer length and dense spatial coverage of seismic reflection profiles of the SEISMARMARA Leg 1 allow to image the deep structure of the marine North Marmara Trough (NMT) on the strike-slip North Anatolian Fault (NAF) west of the destructive Izmit 1999 earthquake. A reflective lower crust and the Moho boundary are detected. They appear upwarped on an E-W profile from the southern Central Basin eastwards, towards more internal parts of the deformed region. Thinning of the upper crust could use a detachment suggested from an imaged dipping intracrustal reflector that would allow upper crustal material to be dragged from beneath it and above the lower crust, accounting for the extensional component but also southwest motion of the southern margin of the NMT. Sections across the eastern half of the NMT, crossing the Cinarcik and Imrali basins, reveal several faults that are active reaching into the basement and have varying strike and proportions of normal and strike-slip displacement. They might be viewed as petals of a large scale negative flower-structure that spreads over a width of 30 km at surface and is rooted deeper in the lithosphere. Under the Central Basin a very thick sediment infill is revealed and its extensional bounding faults are active and imaged as much as 8 km apart down to 6 km depth. We interpret them as two deep-rooted faults encompassing a foundering basement block, rather than being merely pulled-apart from a jog in a strike-slip above a décollement. The deep-basin lengthening would account for only a modest part of the proposed 60 km finite motion since 4 Myr along the same direction oblique to the NMT that sidesteps the shear motion from its two ends. Thus differential motion occurred much beyond the deep basins, like subsidence involving the NMT bounding faults and the intracrustal detachments. The complex partitioned motion localized on active faults with diverse natures and orientations is suggested to

  16. Initial results from MARmara SuperSITE

    NASA Astrophysics Data System (ADS)

    Meral Ozel, Nurcan; Necmioglu, Ocal; Favali, Paolo; Douglas, John; Mathieu, Pierre-Philippe; Geli, Louis; Ergintav, Semih; Oguz Ozel, Asım; Tan, Onur; Gurbuz, Cemil; Erdik, Mustafa

    2014-05-01

    MARSite Project was initiated in November 2012 under the EC/FP-7 framework as an initiative towards establishment of new directions in seismic hazard assessment through focused earth observation in Marmara Region. Within MARSite, collection of the first comprehensive data set of fluids composition around the Sea of Marmara has been accomplished and first insight in the geochemical features of the fluids are expelled from tectonic structures around the Sea of Marmara. GPS time series and velocity fields are periodically updated and a project proposal has been prepared for Supersite initiative to take SAR data and integrate the results with in-situ data sets, which is accepted by the scientific committee of GEOSS. In the meantime, special focus was given to develop the processing algorithms, starting from low level atmospheric correction to high level modeling routines. Considerable progress has been made in the novel design of a multiparameter borehole system consisting of very wide dynamic range and stable borehole (VBB) broad band seismic sensor also incorporating 3-D strain meter, tilt meter, and temperature and local hydrostatic pressure measuring devices. Borehole and surface array locations and borehole bedrock depth of 137 m has been identified. A modeling scheme for the scenario earthquake simulation has been set up in order to realize processing of real-time high-rate GPS data and simulating of scenario earthquakes. The probability of occurrence for the fault segmentation in the Marmara region were calculated using the Poisson, BPT and BPT with a stress interaction models for time intervals of 5-10-30 and 50 years. High resolution seismic reflection and multibeam data in the easternmost Cinarcik basin obtained during the cruise MARMARA 2013 carried out onboard the CNR R/V Urania ship provided information on diffuse gravitational failures. An in situ multi-parameter observational system for landslide monitoring, including displacement, rainfall and seismic

  17. Late glacial to Holocene water level and climate changes in the Gulf of Gemlik, Sea of Marmara: evidence from multi-proxy data

    NASA Astrophysics Data System (ADS)

    Filikci, Betül; Eriş, Kürşad Kadir; Çağatay, Namık; Sabuncu, Asen; Polonia, Alina

    2017-02-01

    Multi-proxy analyses of new piston core M13-08 together with seismic data from the Gulf of Gemlik provide a detailed record of paleoceanographic and paleoclimatic changes with special emphasis on the timing of the connections between the Sea of Marmara (SoM) and the Gulf of Gemlik during the late Pleistocene to Holocene. The deposition of a subaqueous delta sourced from the Armutlu River to the north is attributed to the lowstand lake level at -60 m in the gulf prior to 13.5 cal ka BP. On the basis of the seismic data, it is argued that the higher lake level (-60 m) in the gulf compared to the SoM level (-85 m) attests to its disconnection from the SoM during the late glacial period. Ponto-Caspian assemblages in the lacustrine sedimentary unit covering the time period between 13.5 and 12 cal ka BP represent a relict that was introduced into the gulf by a Black Sea outflow during the marine isotope stage 3 interstadial. Contrary to the findings of previous studies, the data suggest that such an outflow into the Gulf of Gemlik during the late glacial period could have occurred only if the SoM lake level (-85 m) was shallower than the sill depth (-55 m) of the gulf in the west. A robust age model of the core indicates the connection of the gulf with the marine SoM at 12 cal ka BP, consistent with the sill depth (-55 m) of the gulf on the global sea level curve. Strong evidence of a marine incursion into the gulf is well documented by the μ-XRF Sr/Ca data. The available profiles of elemental ratios in core M13-08, together with the age-depth model, imply that a warm and wet climate prevailed in the gulf during the early Holocene (12-10.1 cal ka BP), whereas the longest drought occurred during the middle Holocene (8.2-5.4 cal ka BP). The base of the main Holocene sapropel in the gulf is dated at 10.1 cal ka BP, i.e., 500 years younger than its equivalent in the SoM. The late Holocene is earmarked by warm and wet climate periods (5.0-4.2 and 4.2-2.7 cal ka BP) with some

  18. Undersea acoustic telemetry across the North Anatolian Fault, Marmara Sea: results from the first 6 months of monitoring of the fault displacement

    NASA Astrophysics Data System (ADS)

    Royer, J. Y.; Deschamps, A.; Piete, H.; Sakic, P.; Ballu, V.; Apprioual, R.; Kopp, H.; Lange, D.; Ruffine, L.; Géli, L.

    2015-12-01

    Located in the Marmara Sea, the Istanbul-Silivri segment of the North Anatolian Fault (NAF) is known to be a seismic gap since 1766, although, in the last century, the NAF has caused major devastating earthquakes over most of its extent. This fault segment, void of seismicity, may be either creeping aseismically or blocked and accumulating enough strain to produce an earthquake of magnitude 7 or greater. This section of the NAF may thus represent a major seismic and tsunamigenic hazard for the Istanbul megalopolis, located only 40 km away. The objective of the MARSITE project, funded by the European Union and coordinated by the Observatory of the University of Kandilli (KOERI), is to determine the blocking state of the Istanbul-Silivri fault segment. In this context, an array of 10 acoustic transponders has been deployed on either sides of the fault, in the eastern part of the Kumburgaz Basin, to measure the displacements of the fault over a period of 3 to 5 years. The telemetric beacons (4 from the University of Brest and 6 from the GEOMAR Institute in Kiel) form two arrays fitted in one another. The principle of the experiment is to repeatedly measure the distance (ie two-way-travel time of acoustic pings) between pairs of beacons and thus to monitor the deformation of an array of 9 baselines, 500m to 3000m long, of which 5 cross obliquely the assumed fault trace. The French and German arrays are independent but ensure a redundancy of rangings along common baselines. Each acoustic transponder also monitors the temperature, pressure, sound-velocity and attitude (tiltmeters), every one or two hours. Data are stored in each beacon and can be downloaded from the surface using an acoustic modem. We present here the first 6 months of recording by the French array, from November 1st, 2014 to April 25, 2015. All acoustic transponders worked nominally for 6 months and appear to have remained stable on the seafloor. Recorded sea-bottom temperatures provide evidence for

  19. Seismic structure from sea-bottom to mantle top of the North Anatolian fault in the Sea of Marmara (NW Turkey)

    NASA Astrophysics Data System (ADS)

    Bécel, Anne; Laigle, Mireille; Hirn, Alfred; Bayrakci, Gaye; Taymaz, Tuncay; Yolsal-Ćevikbilen, Seda

    2010-05-01

    New constraints on the deep structure in the North Marmara Trough (NMT) have been investigated during the Seismarmara-Leg1 survey. This survey consisted of a grid of MCS marine deep-penetration multichannel reflection profiles, in addition to coincident reversed and overlapping refraction profiles sounding with the same source recorded on OBS, Ocean Bottom Seismometers and on land stations (Laigle et al., EPSL, 2008, Bécel et al., Tectonoph. 2009 and in press). Results illustrate a complex partitioned motion of the North Anatolian Fault localized on active faults with diverse natures and orientations. MCS sections crossing the Cinarcik and Imrali basins in the eastern half of the NMT, reveal several active faults that involve the basement and have changing strike and proportions of normal and strike-slip displacement. They might be viewed as petals of a large scale negative flower-structure that spreads over a width of 30 km at surface and is rooted in the deeper lithosphere. Under the Central Basin, a very deep sediment infill is revealed and its extensional bounding faults are active and imaged down to 6 km depth. We interpret them as two deep-rooted faults encompassing a foundering basement block. The segment between the deep eastern basins and the Central Basin contains also a tilted basement block, with the subdued Kumburgaz marine basin in its hanging wall and a sediment-filled one on top of its southward tilted footwall. The width of the NMT, and the sizes of the tilted blocks it contains and basins they control, vary along it. Nevertheless a similar process prevailed: a deformation partitioned over more than one or even two faults across the NMT that may have changed activity with time at places. For the deeper structure, with the strong seismic source recorded up to 200 km offset, the Moho boundary is positively identified from reversed observations at large offset by land stations, as well as at several OBS. A significant and sharp reduction in its depth

  20. Creeping and locked segments along the Main Marmara Fault

    NASA Astrophysics Data System (ADS)

    Schmittbuhl, Jean; Karabulut, Hayrullah; Lengliné, Olivier; Bouchon, Michel

    2014-05-01

    It is known since the last 1999 Izmit earthquake that the North Anatolian Fault is hosting a final important seismic gap along a 150 km region that corresponds to the Main Marmara Fault (MMF) below the Sea of Marmara. The gap is owing to a major locking zone where slip along the fault is blocked despite a significant remote plate boundary loading (23 mm/yr). After about 250 years of quiescence the fault is now very close to failure. Unfortunately any attempt of prediction which relies on a very fine monitoring of the fault behavior, is strongly limited by the sea coverage. Direct observations in particular from geodetic measurements are indeed very difficult. However, local seismicity along the MMF provides crucial indirect evidences. The present work is based on this approach and includes precise geographical and depth locations from a large compilation of seismic stations around the Sea of Marmara. We aim at interpreting micro-earthquake spatial distribution in terms of regional geodynamical information and compare it to other approaches like geodesy. From the geographical and depth distribution of micro-seismicity between 2007 and 2012, three domains can be defined along the Main Marmara Fault (MMF) : the West Marama (WM) zone which includes the Tekidag and Central Basins where seismicity is abundant and well distributed in depth (from surface to 17 km) including several vertically extended clusters, the Kumburgaz basin (KB) in the center zone of the Marmara Sea where seismicity is very spare, and the Cinarcik basin (CB) where seismicity is uniformly distributed along the MMF but mostly at depth along a narrow zone (except at both ends of this basin where vertically extended swarms also exist). We evidence three different behaviors. The western Marmara segment is mostly creeping on the contrary to the central Kumburgaz Basin fault zone which is entirely locked as well as possible upper sub-regions of the Princess Island fault and/or the Tekirdag basin

  1. Reassessment of probabilistic seismic hazard in the Marmara region

    USGS Publications Warehouse

    Kalkan, E.; Gulkan, Polat; Yilmaz, N.; Celebi, M.

    2009-01-01

    In 1999, the eastern coastline of the Marmara region (Turkey) witnessed increased seismic activity on the North Anatolian fault (NAF) system with two damaging earthquakes (M 7.4 Kocaeli and M 7.2 D??zce) that occurred almost three months apart. These events have reduced stress on the western segment of the NAF where it continues under the Marmara Sea. The undersea fault segments have been recently explored using bathymetric and reflection surveys. These recent findings helped scientists to understand the seismotectonic environment of the Marmara basin, which has remained a perplexing tectonic domain. On the basis of collected new data, seismic hazard of the Marmara region is reassessed using a probabilistic approach. Two different earthquake source models: (1) the smoothed-gridded seismicity model and (2) fault model and alternate magnitude-frequency relations, Gutenberg-Richter and characteristic, were used with local and imported ground-motion-prediction equations. Regional exposure is computed and quantified on a set of hazard maps that provide peak horizontal ground acceleration (PGA) and spectral acceleration at 0.2 and 1.0 sec on uniform firm-rock site condition (760 m=sec average shear wave velocity in the upper 30 m). These acceleration levels were computed for ground motions having 2% and 10% probabilities of exceedance in 50 yr, corresponding to return periods of about 2475 and 475 yr, respectively. The maximum PGA computed (at rock site) is 1.5g along the fault segments of the NAF zone extending into the Marmara Sea. The new maps generally show 10% to 15% increase for PGA, 0.2 and 1.0 sec spectral acceleration values across much of Marmara compared to previous regional hazard maps. Hazard curves and smooth design spectra for three site conditions: rock, soil, and soft-soil are provided for the Istanbul metropolitan area as possible tools in future risk estimates.

  2. Polycyclic aromatic hydrocarbon contamination in coastal sediments of the Izmit Bay (Marmara Sea): case studies before and after the Izmit Earthquake.

    PubMed

    Tolun, L; Martens, D; Okay, O S; Schramm, K W

    2006-08-01

    Izmit Bay and its coastal environment was strongly affected by the August 17th, 1999 Izmit Earthquake. The changes in the Bay ecosystem and its chemical oceanography have been studied in detail previously [Okay, O.S., Tolun, L, Telli-Karakoç, F., Tüfekçi, V., Tüfekçi, H. And Morkoç, E. 2001. Yzmit Bay ecosystem after Marmara earthquake and subsequent fire: The long-term data. Marine Pollution Bulletin 42, 361-369; Balkýs, N. 2003. The effect of Marmara (Izmit ) Earthquake on the chemical oceanography of Izmit Bay, Turkey. Marine Pollution Bulletin 46, 865-878.]. In this study surface sediments collected from the Izmit Bay before and after the earthquake have been analysed for total and individual (14 compounds) polycyclic aromatic hydrocarbons (PAH). Analyses have been performed by high performance liquid chromatography with fluorescence detection (HPLC/FD). Before the earthquake, total PAH concentrations in the Bay sediments ranged from 120 to 8900 ng/g while after the earthquake PAH concentrations varied between 240 and 11,400 ng/g. Molecular indices based on isomeric PAH ratios used to differentiate the pollution sources, clearly indicate the differences in molecular distribution of PAHs before and after the earthquake. Sediment data obtained before the earthquake shows that most of the contamination originated from high temperature pyrolytic inputs while after the earthquake it originated from petrogenic sources. This difference emphasises the environmental impact of uncontrolled discharges from petroleum industries after the earthquake. The LMW/HMW ratio (sum of the low molecular weight PAHs / the sum of higher molecular weight PAHs) predominance also changed after the earthquake as a result of the strong water movements. According to the characteristics of aromatic rings distributed in the bay sediments, the soluble parts of the total PAH were probably transferred to the water column after the earthquake as a result of resuspension process. The TEL

  3. The influence of atmospheric circulation types on regional patterns of precipitation in Marmara (NW Turkey)

    NASA Astrophysics Data System (ADS)

    Baltacı, H.; Kındap, T.; Ünal, A.; Karaca, M.

    2017-02-01

    In this study, regional patterns of precipitation in Marmara are described for the first time by means of Ward's hierarchical cluster analysis. Daily values of winter precipitation data based on 19 meteorological stations were used for the period from 1960 to 2012. Five clusters of coherent zones were determined, namely Black Sea-Marmara, Black Sea, Marmara, Thrace, and Aegean sub-regions. To investigate the prevailing atmospheric circulation types (CTs) that cause precipitation occurrence and intensity in these five different rainfall sub-basins, objective Lamb weather type (LWT) methodology was applied to National Centers of Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis of daily mean sea level pressure (MSLP) data. Precipitation occurrence suggested that wet CTs (i.e. N, NE, NW, and C) offer a high chance of precipitation in all sub-regions. For the eastern (western) part of the region, the high probability of rainfall occurrence is shown under the influence of E (SE, S, SW) atmospheric CTs. In terms of precipitation intensity, N and C CTs had the highest positive gradients in all the sub-basins of the Marmara. In addition, although Marmara and Black Sea sub-regions have the highest daily rainfall potential during NE types, high daily rainfall totals are recorded in all sub-regions except the Black Sea during NW types.

  4. Earthquake and Tsunami Disaster Mitigation in the Marmara Region and Disaster Education in Turkey Part2

    NASA Astrophysics Data System (ADS)

    Kaneda, Yoshiyuki; Ozener, Haluk; Meral Özel, Nurcan

    2016-04-01

    Turkey is one of seismogenic countries with destructive earthquakes. In Turkey, the 1999 Izumit Earthquake as the destructive earthquake occurred along the North Anatolian fault. This fault is crossing the Marmara sea. In this SATREPS project, Marmara Sea should be focused on because of a seismic gap in the North Anatolian fault. Istanbul is located around the Marmara Sea, so, if next earthquake in the Marmara will occur near Istanbul, fatal damages will be generated as compound damages including Tsunami and liquefaction etc. The Japan and Turkey can share our own experiences during past damaging earthquakes and we can prepare for future large earthquakes in cooperation with each other. In earthquakes in Tokyo area and Istanbul area as the destructive earthquakes near high population cities, there are common disaster researches and measures in each country. For disaster mitigation, we are progressing multidisciplinary researches in this SATREPS project. Our goals of this SATREPS project are as follows, This project is composed of four research groups. 1) The first group is Marmara Earthquake Source region observationally research group. This group has 4 sub-themes such as Seismicity, Geodesy, Electromagnetics and Trench analyses. 2) The second group focuses on scenario researches of earthquake occurrence along the North Anatolia fault and precise tsunami simulation in the Marmara region. 3) Aims of the third group are improvements and constructions of seismic characterizations and damage predictions based on observation researches and precise simulations. 4) The fourth group is promoting disaster educations using research result visuals. In this SATREPS project, we will integrate these research results for disaster mitigation in Marmara region and disaster education in Turkey. Finally, these results and knowledges will be applied to Japanese disaster mitigation researches and disaster educations. We will have a presentation of the updated results of this SATREPS

  5. Imaging Fluid-Rich Zones by Magnetotelluric Method at South Marmara Region, Turkey

    NASA Astrophysics Data System (ADS)

    Cengiz, Özlem; Bülent Tank, Sabri; Tolak Çiftçi, Elif; Kaya, Tülay; Ogawa, Yasuo; Honkura, Yoshimori; Kemal Tunçer, Mustafa; Matsushima, Masaki; Oshiman, Naoto; Çelik, Cengiz

    2013-04-01

    After the mainshock of 1999 İzmit (Turkey) earthquake, scientists have undertaken various kinds of observations in the Marmara region in order to increase understanding of crustal properties of North Anatolian Fault Zone (NAFZ). Most of these studies focused on the east Marmara region since the destructive earthquakes were occurring there. Considering the westward migration of significant earthquakes on the North Anatolian Fault (NAF), the next destructive earthquake is likely to occur beyond the westernmost part of 1999 İzmit earthquake epicenter, in or around Marmara Sea. For this reason, south of Marmara Sea was chosen as the survey area. Wide-band (320-0.0005 Hz) magnetotelluric (MT) data at sixteen sounding locations along two parallel profiles at south Marmara region were collected to improve the understanding of the crustal electrical conductivity structure. Both profiles are crossing several branches of North Anatolian Fault. The results were achieved by performing two-dimensional (2D) inversions of MT data with the transverse electric (TE) and transverse magnetic (TM) modes. These results show a relatively complex structure down to 4 km depth. The electrical resistivity pattern below this depth indicates a simpler structure with conductors (10 Ωm) beneath the northern ends of both profiles. While these deep conductive zones are attributed to partially melting in the crust, the highly resistive zones are associated with low fluid condition and high rigidity. In addition, the features characterized in geo-electric models correlate well with known faults in the survey area. The South Marmara Fault (SMF) possibly corresponds to a lateral resistive-conductive interface between Manyas-Karacabey basin and Bandirma-Karada uplift on the west (PW) and Uluabat uplift and Mudanya uplift on the east (PE) profiles.

  6. The history of Post-Miocene sea level change: Inferences from stratigraphic modeling of Enewetak Atoll

    NASA Astrophysics Data System (ADS)

    Quinn, Terrence M.

    1991-04-01

    The history of post-Miocene sea level change has been investigated using a quantitative, one-dimensional stratigraphic forward model. The stratigraphic model produces synthetic stratigraphies, including mineralogy and sediment age versus depth, in response to changes in sea level, subsidence, sedimentation, and diagenesis. Model outputs, using sea level curves inferred from passive margin sequence stratigraphy and deep-sea foraminiferal oxygen isotope stratigraphy, were compared to the post-Miocene stratigraphy of Enewetak Atoll. Modeling results support high-frequency (104 to 105 years) fluctuations of post-Miocene sea level. Post-Miocene sea level elevations significantly greater than modern sea level elevation are not easily reconciled with the stratigraphy of Enewetak Atoll. Model/data fit is maximized when a rapid subsidence rate for Enewetak Atoll is used. Alternatively, model/data fit may be maximized using a lower subsidence rate for Enewetak and having post-Miocene sea level elevations significantly lower than modem sea level elevation. Given the present state of knowledge, much work is still needed to accurately decipher the record of post-Miocene sea level change.

  7. Sea Level Rise and Decadal Variations in the Ligurian Sea Inferred from the Medimaremetre Measurements.

    NASA Astrophysics Data System (ADS)

    Karpytchev, M.; Coulomb, A.; Vallee, M.

    2015-12-01

    Estimations of sea level rise over the last centuries are mostly based on the rare historical sea level records from tide gauge stations usually designed for navigational purposes. In this study, we examine the quality of sea level measurements performed by a mean sea level gauge operated in Nice from 1887 to 1909 and transferred to the nearby town of Villefranche-sur-Mer in 1913 where it stayed in operation untill 1974. The mean sea level gauges, called medimaremetres, were invented for geodetic studies and installed in many French ports since the end of the XIX century. By construction, the medimaremetre was connected to the sea through a porous porcelain crucible in order to filter out the tides and higher frequency sea level oscillations. Ucontrolled properties of the crucible and some systematic errors made the medimaremetre data to be ignored in the current sea level researches. We demonstrate that the Nice-Villefranche medimaremetre measurements are coherent with two available historical tide gauge records from Marseille and Genova and a new century-scale sea level series can be build up by combining the medimaremetre data with the those recorded by a tide gauge operating in Nice since the 1980s. We analyse the low frequency variabilities in Marseille, Nice-Villefranche and Genova and get new insights on the decadal sea level variations in the Ligurian Sea since the end of the XIX century.

  8. Integrated multidisciplinary fault observation in Marmara Through MARSite - Project Achievements

    NASA Astrophysics Data System (ADS)

    Meral Ozel, N.; Necmioglu, O.; Favali, P.; Ergintav, S.; Ozel, O.; Bigarré, P.; Géli, L.; Aochi, H.; Bossu, R.; Cakir, Z.; Zulfikar, C.; Sesetyan, K.; Douglas, J.

    2015-12-01

    This presentation provides overview of the achievements of the 3-year long EC/FP-7 MARSite Project started in November 2012, which aimed to coordinate research groups ranging from seismology to gas geochemistry in a comprehensive monitoring activity developed both in the Marmara Region based on collection of multidisciplinary data to be shared, interpreted and merged in consistent theoretical and practical models suitable for the implementation of good practices to move the necessary information to the end users in charge of seismic risk management of the region. In addition, processes involved in earthquake generation and the physics of short-term seismic transients, 4D deformations to understand earthquake cycle processes, fluid activity monitoring and seismicity under the sea floor using existing autonomous instrumentation, early warning and development of real-time shake and loss information, real- and quasi-real-time earthquake and tsunami hazard monitoring and earthquake-induced landslide hazard topics are also covered within MARSite. In particular, achievements and progress in the design and building of a multi-parameter borehole system consisting of very wide dynamic range and stable borehole (VBB) broad band seismic sensor, with incorporated 3-D strain meter, tilt meter, and temperature and local hydrostatic pressure measuring devices would be reported. This work is funded by the project MARsite - New Directions in Seismic Hazard assessment through Focused Earth Observation in the Marmara Supersite FP7-ENV.2012 6.4-2, Grant 308417.

  9. SeaBase: a multispecies transcriptomic resource and platform for gene network inference.

    PubMed

    Fischer, Antje H L; Mozzherin, Dmitry; Eren, A Murat; Lans, Kristen D; Wilson, Nathan; Cosentino, Carlo; Smith, Joel

    2014-07-01

    Marine and aquatic animals are extraordinarily useful as models for identifying mechanisms of development and evolution, regeneration, resistance to cancer, longevity and symbiosis, among many other areas of research. This is due to the great diversity of these organisms and their wide-ranging capabilities. Genomics tools are essential for taking advantage of these "free lessons" of nature. However, genomics and transcriptomics are challenging in emerging model systems. Here, we present SeaBase, a tool for helping to meet these needs. Specifically, SeaBase provides a platform for sharing and searching transcriptome data. More importantly, SeaBase will support a growing number of tools for inferring gene network mechanisms. The first dataset available on SeaBase is a developmental transcriptomic profile of the sea anemone Nematostella vectensis (Anthozoa, Cnidaria). Additional datasets are currently being prepared and we are aiming to expand SeaBase to include user-supplied data for any number of marine and aquatic organisms, thereby supporting many potentially new models for gene network studies. SeaBase can be accessed online at: http://seabase.core.cli.mbl.edu.

  10. Sea ice thickness in the Weddell Sea, inferred from upward looking sonar measurements

    NASA Astrophysics Data System (ADS)

    Behrendt, Axel; Dierking, Wolfgang; Witte, Hannelore

    2014-05-01

    Sea ice has been routinely monitored by satellites since 1979. However, thickness measurements of sea ice are still very sparse, especially in the Southern Hemisphere. Satellite altimetry still provides relatively uncertain estimates of ice thickness. Today, the only tool for monitoring sea ice thickness over long time periods with highest accuracy (5-10 cm) are moored upward looking sonars (ULS). The instruments measure the subsurface portion (draft) of the ice, which can be converted into total ice thickness. We present a data set of ULS time series from 13 positions in the Atlantic sector of the Southern Ocean (Weddell Sea), which were made in different years between 1990 and 2010. Monthly mean sea ice draft shows high interannual variability and can reach more than 3 m in the dynamic coastal regions of the eastern and western Weddell Sea. The thinnest ice is found away from the coast in the eastern Weddell Sea and rarely exceeds 1 m in the monthly mean. In single years the ULS data allow for a clear discrimination between thermodynamic ice growth and dynamic ice growth due to rafting and ridging of the floes. We demonstrate that the thermodynamic ice thickness can reach its theoretical maximum value of 1 m in the central Weddell basin. Despite significant gaps, the presented data set provides an important validation tool for satellite algorithms and sea ice models.

  11. Integrated multidisciplinary fault observation in Marmara Through MARSite - Project Progress

    NASA Astrophysics Data System (ADS)

    Meral Ozel, Nurcan; Necmioglu, Ocal; Oguz Ozel, Asım; Ergintav, Semih; Geli, Louis Louis; Favali, Paolo; Guralp, Cansun; Douglas, John; Mathieu, Pierre-Philippe; Tan, Onur; Gürbüz, Cemil; Erdik, Mustafa

    2015-04-01

    This presentation provides a progress overview of the EC/FP-7 MARSite Project started in November 2012, which aims to coordinate research groups ranging from seismology to gas geochemistry in a comprehensive monitoring activity developed both in the Marmara Region based on collection of multidisciplinary data to be shared, interpreted and merged in consistent theoretical and practical models suitable for the implementation of good practices to move the necessary information to the end users in charge of seismic risk management of the region. In addition, processes involved in earthquake generation and the physics of short-term seismic transients, 4D deformations to understand earthquake cycle processes, fluid activity monitoring and seismicity under the sea floor using existing autonomous instrumentation, early warning and development of real-time shake and loss information, real- and quasi-real-time earthquake and tsunami hazard monitoring and earthquake-induced landslide hazard topics are also covered within MARSite. This presentation would provide a report on the progress achieved during the half-life of the project. In this respect, the main data server for the integration of real time network data has been finalized. Daily evaluation of online spring water and soil radon gas data in relation to seismic activity is in place, together with the continuous GPS data processing. A significant combination of postseismic (viscoelastic) deformation and afterslip was detected in the western segment of the 1999 Izmit rupture plane based on InSAR modeling. The optimum borehole depths have been identified based on seismic reflection studies and GURALP Systems is continuing its work on the manufacturing the borehole system. Seismic risk study for IGDAS Natural Gas Network including pipelines and its components has been carried out with several earthquake scenarios in Marmara Sea and an automatic shut-off algorithm has been developed for the automatic shut-off of the gas

  12. Integrated Multidisciplinary Fault Observation in Marmara Through MARSite

    NASA Astrophysics Data System (ADS)

    Meral Ozel, N.; Necmioglu, O.; Ozel, A. O.; Ergintav, S.; Tan, O.; Geli, L. B.; Favali, P.; Guralp, C. M.; Douglas, J.; Mathieu, P. P.; Gurbuz, C.; Erdik, M. O.

    2014-12-01

    MARSite Project, initiated in November 2012 under the EC/FP-7 framework, aims to coordinate research groups ranging from seismology to gas geochemistry in a comprehensive monitoring activity developed both in the Marmara Region based on collection of multidisciplinary data to be shared, interpreted and merged in consistent theoretical and practical models suitable for the implementation of good practices to move the necessary information to the end users in charge of seismic risk management of the region. In addition, processes involved in earthquake generation and the physics of short-term seismic transients, 4D deformations to understand earthquake cycle processes, fluid activity monitoring and seismicity under the sea floor using existing autonomous instrumentation, early warning and development of real-time shake and loss information, real- and quasi-real-time earthquake and tsunami hazard monitoring and earthquake-induced landslide hazard topics are also covered within MARSite. This presentation would provide a report on the progress achieved during the half-life of the project. In this respect, the main data server for the integration of real time network data has been finalized. Daily evaluation of online spring water and soil radon gas data in relation to seismic activity is in place, together with the continuous GPS data processing. A significant combination of postseismic (viscoelastic) deformation and afterslip was detected in the western segment of the 1999 Izmit rupture plane based on InSAR modeling. The optimum borehole depths have been identified based on seismic reflection studies and GURALP Systems is continuing its work on the manufacturing the borehole system. Seismic risk study for IGDAS Natural Gas Network including pipelines and its components has been carried out with several earthquake scenarios in Marmara Sea and an automatic shut-off algorithm has been developed for the automatic shut-off of the gas flow at the IGDAS district regulators

  13. The Crustal Structure Of The Marmara Region Using Receiver Function Analysis

    NASA Astrophysics Data System (ADS)

    Büyükakpınar, Pınar; Gürbüz, Cemil; Zor, Ekrem

    2016-04-01

    The Marmara region is a rapidly deforming area with high seismic activity in the northwestern Turkey. In order to further understand the crustal structure in the region, we present results from receiver function analysis using the permanent stations in the region by applying H-κ stacking algorithm which gives crustal thickness and Vp/Vs ratio beneath a station. 40 land stations between January of 2008 and April of 2012, and 5 cabled Sea Bottom Observatories which were deployed at the end of 2010 by KOERI located between 40.2°- 41.2° N and 26.5°- 30.5° E were included in the analysis. Approximately 250 teleseismic events from a wide range of epicentral distances with magnitudes greater than Mw 5.5 are used to obtain receiver functions. Furthermore, in order to calculate the receiver functions in time domain using iterative deconvolution technique suggested by Ligorria and Ammon (1999). Consequently, the crustal structure of the region has been reasonably defined and compared with the other studies. As a consequence of the receiver function analysis, the Moho depth variation map and Vp/Vs ratio map were plotted. The Moho depth on average is 31 km. There are no sharp changes in the crustal thickness of the Marmara Region except North Marmara Trough because basin structure of the Marmara Sea where crustal thickness reaches up to 26 km in the same region was not observed. Furthermore, we found overall average Vp/Vs ratio of 1.74, for the region but we obtained low Vp/Vs ratios in the stations located near Çınarcık Basin which varies between 1.64 - 1.74 indicating the effect of basin structure in the area and North Marmara where Vp/Vs ratios vary between 1.60 and 1.70 which is related to the sediment structure of the area. We also acquired higher Vp/Vs ratios which are between 1.86 and 1.96 in the Western Marmara Region. This can be due to increasing mafic content in this area. Additionally, an attempt has been made to invert the radial receiver function of the

  14. Long-lasting seismic repeaters in the Central Basin of the Main Marmara Fault

    NASA Astrophysics Data System (ADS)

    Schmittbuhl, J.; Karabulut, H.; Lengliné, O.; Bouchon, M.

    2016-09-01

    The Main Marmara Fault which crosses the whole Marmara Sea is a significant seismic gap along the North Anatolian Fault. Here we show that nine long-lasting strike-slip seismic repeaters exist below the Central Basin within the seismogenic zone, in a 10 km region where deep creep was previously suggested from the analysis of the local seismicity. The typical recurrence time was 8 months during the 2008-2015 period. The cumulative slip of the repeating sequence appears to be compatible with the regional geodetic slip rate if they are assumed to be part of a large single asperity (10 km). The repeaters also exhibit short-term crises and are possibly related to bursts of creep.

  15. Performance of Network Based EEW Systems in Marmara Region; VS, ElarmS-2 and PRESTo

    NASA Astrophysics Data System (ADS)

    Kuyuk, H. S.; Pinar, A.; Comoglu, M.; Erdik, M. O.

    2015-12-01

    Several earthquake early warning algorithms are in operation in various countries. Kandilli Observatory and Earthquake Engineering Institute (KOERI) implemented and recently running three different EEWS within KOERI network in Marmara Region. Due to high probability of an earthquake with Mw > 7 in the next 30 years in the Marmara Sea, there is an urgent need to evaluate existing EEWS performance and to find out how reliable an EEW is in terms of calculating time, location, magnitude of an earthquake in the region. Here we assessed performance of Virtual Seismologist (VS), Earthquake Alarm System-2 (ElarmS-2) and PRobabilistic and Evolutionary early warning SysTem (PRESTo) which are developed at Caltech, UC Berkeley and University of Naples respectively and are being monitored for over six months. We choose four representative earthquakes that are detected by three algorithm and evaluated their performances. We found each algorithm has its own strengths and weakness in calculating source parameters. Even though, algorithms are not optimized, cities around the Marmara Sea could get up to 50 seconds warning time with existing infrastructure. First alert could be given in 12 seconds after origin time and blind-zone could get minimum 40 km radius. The main reason of delays on detecting earthquake is packet size of data (7 seconds in average). We confirm that SeisComp3 platform requires additional time to locate earthquakes and it needs to be optimized for EEWS. This study could help algorithm developer of three EEWS to optimize their systems in other seismically active region and different earthquake environment. We believe results derived from this study will provide precious information for both habitants in Marmara region and geo-scientist.

  16. Global Aerosol Radiative Forcing Derived from Sea WiFS-Inferred Aerosol Optical Properties

    NASA Technical Reports Server (NTRS)

    Chou, Ming-Dah; Chan, Pui-King; Wang, Menghua

    1999-01-01

    Aerosol optical properties inferred from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) radiance measurements are used to compute the aerosol shortwave radiative forcing using a radiative transfer model. The aerosol optical thickness at the wavelength of 865-nm is taken from the SeaWIFS archive. It is found that the nominal optical thickness over oceans ranges from 0.1 to 0.2. Using a maritime aerosol model and the radiances measured at the various SeaWiFS channels, the Angstrom exponent is determined to be 0.2174, the single-scattering albedo to be 0.995, and the asymmetry factor to be 0.786. The radiative transfer model has eight bands in the visible and ultraviolet spectral regions and three bands in the near infrared. It includes the absorption due to aerosols, water vapor, carbon dioxide, and oxygen, and the scattering due to aerosols and gases (Rayleigh scattering). The radiative forcing is computed over global oceans for four months (January, April, July, and October, 1998) to represent four seasons. It is found that the aerosol radiative forcing is large and changes significantly with seasons near the continents with large-scale forest fires and desert dust. Averaged over oceans and the four months, the aerosol radiative forcing is approximately 7 W/sq m at the top of the atmosphere. This large radiative forcing is expected to have a significant cooling effect on the Earth's climate as implied from simulations of a number of general circulation models.

  17. Modelling the earthquake intensities: A case study on the faults of the Marmara Region, NW Turkey

    NASA Astrophysics Data System (ADS)

    Erturac, M. K.; Tuysuz, O.

    2003-04-01

    North Anatolian Fault Zone is the biggest neo-tectonic structure of the Asia Minor. 17 August 1999 M=7.4 Izmit earthquake was the seventh in a sequence of westward migrating earthquakes along this fault. The earthquake sequence which began with the 1939 Erzincan earthquake, caused rupture of 1000 km section of the fault with maximum displacement of 7.5 meters. The time interval between these earthquakes varied from 3 months to 32 years. Stress triggering has been invoked to explain the 60-year sequence of earthquakes rupturing toward the west, in which every event promoted the next. The Izmit earthquake increased the probability of future earthquake in the Sea of Marmara region. GPS, historical and instrumental earthquake data, and estimated stress triggering indicate a remarkable probability (62 % ±15) of a strong shaking in the Marmara Sea region during the next 30 years which threats the city of Istanbul. Active faults in the Sea of Marmara is mapped and published by different companies. By using these recent data, local geology, site conditions and attenuation relationships, it is possible to estimate the degree of shaking for a future earthquake. In this study we used geographical information systems as a tool for such a modeling. In the light of fault length, previous earthquake data and GPS measurements we attributed possible magnitudes for each segment. Then we used different attenuation relationships to obtain the distribution of possible peak ground accelerations. These data is correlated with the recorded attenuations. After choosing appropriate formula, the peak ground accelerations converted to intensity values. The model is also applied to data obtained during the 1999 Izmit (Mw 7.3) and Duzce (Mw 7.2) earthquakes to test the consistency of the results. In this presentation models for different fault segments will be presented.

  18. Abrupt Changes in the Marmara Pelagic Ecosystem during the recent jellyfish Liriope tetraphylla invasion and mucilage events

    NASA Astrophysics Data System (ADS)

    Erkan Kideys, Ahmet; Yüksek, Ahsen; Sur, Halil Ibrahim

    2013-04-01

    In this study, meteorological and hydrographical conditions as well as chemical and biological parameters have been examined for the period 2005-2009 to determine the impact and cause of the massive mucilage phenomenon observed in the Sea of Marmara in October 2007. Results showed that there is a decrease pattern in chl concentration as well as both phytoplankton and zooplankton abundances from August till October in 2007 whilst the jellyfish Liriope tetraphylla had bloom levels. This period coincided with the maximum intensity of pelagic fishing throughout the years. Nitrogen/phosphate ratio increased prior to the mucilage formation. Invasive Liriope tetraphylla abundance increased exponentially in August and died in masses as a result of starvation and meteorological / oceanographic conditions. In October, following the mucilage matter production another new species for the region Gonyaulax fragilis was observed in high abundance through the basin. It is worthy to note that during basin wide samplings conducted in the Sea of Marmara in both 2005 and 2006, high abundances of Liriope tetraphylla have been detected particularly at the northern parts where no mucilage event was observed. We suggest that overfishing in the Sea of Marmara provided a ground for the establishment of the invasive jellyfish and accompanying mucilage event was due to by synergic combinations of several factors.

  19. Groundwater temperature transients on the Armutlu peninsula, eastern Marmara region

    NASA Astrophysics Data System (ADS)

    Woith, Heiko; Caka, Deniz; Seyis, Cemil; Italiano, Francesco; Celik, Cengiz; Wang, Rongjiang; Baris, Serif

    2016-04-01

    Since many years MAM and GFZ in co-operation with Kocaeli University (KU) operate fluid monitoring stations around the Sea of Marmara. In the frame of MARsite (MARsite has received funding from the European Union's Seventh Programme for research, technological development and demonstration under grant agreement No 308417) these networks were jointly evaluated for the first time. The on-land fluid monitoring networks continuously monitor the following parameters: soil radon (21 sites), temperature and conductivity of thermal springs (9 sites) operated by MAM covering the whole Marmara region; fluid pressure and water level/temperature (8 sites) within ARNET operated by GFZ/KU. ARNET is a combined seismological/hydrogeological monitoring network covering the Armutlu peninsula located SE of Istanbul. Additional to the geothermal wells and springs - our main target to detect transients of potentially seismo-tectonic origin - three shallow groundwater wells (tenth of meters deep) are being operated to identify and quantify seasonal variations, and meteorological influences like rainfall and snowmelt. But it turned out that these shallow aquifer systems showed very stable conditions with very small annual temperature amplitudes (0.2 - 0.3°C). One of these shallow monitoring wells is located just south of Lake Iznik (in the village of Sölöz) very close to the southern branch of the North Anatolian Fault Zone. Water level showed a steady decreasing trend since June 2012. This trend resulted in a data gap starting in January 2014, when the water level dropped below the sensor position. After adjusting the sensor position, positive spikes in the borehole temperature were recorded in June and August 2014, and again in 2015. The spikes are characterised by a sharp temperature increase followed by a decay lasting several days until the pre-event temperature was reached again. Since the spikes occurred on two independent logger systems, and since they lasted several days, a

  20. Seismic anisotropy along the Cyprean arc and northeast Mediterranean Sea inferred from shear wave splitting analysis

    NASA Astrophysics Data System (ADS)

    Yolsal-Çevikbilen, Seda

    2014-08-01

    The Cyprean arc is considered to be a convergent boundary in the Eastern Mediterranean where the African plate is being subducted beneath the Anatolian plate. Mapping the lateral variations of seismic anisotropy parameters can provide essential hints to mantle dynamics and flow patterns in relation to the geometry and style of deformation developed under different pressure, temperature conditions around the subducting African lithosphere. In this study, seismic anisotropy parameters, fast polarization directions (ϕ) and delay times (δt) beneath the Cyprean arc and NE Mediterranean Sea are inferred from the shear wave splitting analysis performed on core-mantle refracted teleseismic shear waves (SKS phases). Earthquake data used in the present work are extracted from the continuous recordings of 8 broad-band seismic stations located in the study region for a time period during 1999 and 2012. The overall results exhibits clear evidences of mantle anisotropy with relatively uniform NE-SW aligned fast polarization directions. No abrupt changes in fast polarization directions (ϕ) are observed. However, near the Dead Sea Transform Fault, ϕ values tend to rotate from NE-SW to N-S and NW-SE in accordance with Pn anisotropy observations. Delay times (δt) vary between 0.61 s ± 0.10 s and 1.90 s ± 0.13 s. The range of delay times are generally consistent with those observed in the mantle rather than implying a crustal anisotropy. A predominant pattern of NNE-SSW fast polarization directions that is coherent with earlier SKS splitting measurements observed beneath north, central and East Anatolia suggests a SW directed asthenospheric flow caused by slab rollback process along the Hellenic and Cyprean arcs. Furthermore, apparent splitting parameters did not exhibit any significant directional dependence which may imply possibility of the presence of anisotropic models with two-layer anisotropy or dipping axis of symmetry beneath the northeast Mediterranean Sea and

  1. Measured Correlation Between Roll-Vortex Signatures and Radar-Inferred Sea Surface Roughness

    NASA Technical Reports Server (NTRS)

    Vandemark, Douglas; Mourad, Pierre; Crawford, Tim; Vogel, Chris

    2000-01-01

    This paper presents aircraft measurements of near-surface atmospheric boundary layer roll signatures and radar-derived sea surface roughness. These data are completely coincident in space and time and this unique feature supports attempts to definitively link SAR backscatter signatures to boundary layer roll impacts. The open-ocean data were collected at an altitude of 20 in from NOAA's Long-EZ aircraft using its turbulence probe and down-looking Ka-band radar scatterometer, Several flight legs of 20-30 km were flown with a heading across the wind direction, which is also roughly perpendicular to the roll vortices. We find remarkable correlation between measured modulations in the along-wind component of wind speed and radar backscatter for the spatial scale of I to 1.5 kin. Close agreement between normalized modulation amplitudes suggests the radar-inferred surface slope variance is changing linearly with wind speed. These data were collected within 30 minutes of a RADARSAT SAR overpass where apparent boundary layer impacts of the same orientation and spatial dimension are prevalent in the SAR backscatter image. Quantitative comparison between modulations in the aircraft and satellite radar data will be discussed.

  2. New Directions in Seismic Hazard Assessment through Focused Earth Observation in the MARmara SuperSITE

    NASA Astrophysics Data System (ADS)

    Meral Ozel, Nurcan; Necmioglu, Ocal; Favali, Paolo; Douglas, John; Mathieu, Pierre Philippe; Geli, Louis; Tan, Onur; Ergintav, Semih; Oguz Ozel, A.; Gurbuz, Cemil; Erdik, Mustafa

    2013-04-01

    Among the regions around the Mediterranean Sea for which earthquakes represent a major threat to their social and economic development, the area around the Marmara Sea, one of the most densely populated parts of Europe, is subjected to a high level of seismic hazard. For this region the MARSITE project is proposed with the aim of assessing the "state of the art" of seismic risk evaluation and management at European level. This will be the starting point to move a "step forward" towards new concepts of risk mitigation and management by long-term monitoring activities carried out both on land and at sea. MARsite will serve as the platform for an integrated, multidisciplinary, holistic and articulated framework for dealing with fault zone monitoring, capable of developing the next generation of observatories to study earthquake generation processes. The main progress will be the fusion of ground- and space-based monitoring systems dedicated to geo-hazard monitoring. All data (space/sea-bottom/seismology/borehole/geochemistry) will flow to KOERI and hosted in and served via a secure server. The MARSITE project aims to coordinate research groups with different scientific skills (from seismology to engineering to gas geochemistry) in a comprehensive monitoring activity developed both in the Marmara Sea and in the surrounding urban and country areas. The project collects multidisciplinary data, to be shared, interpreted and merged in consistent theoretical and practical models suitable for the implementation of good practices to move the necessary information to the end users in charge of seismic risk management of the Istanbul-Marmara Sea area. Marsite is divided into eleven work packages that consider the processes involved in earthquake generation and the physics of short-term seismic transients, 4D deformations to understand earthquake cycle processes, fluid activity monitoring and seismicity under the sea floor using existing autonomous instrumentation, early warning

  3. Ground motion simulations in Marmara (Turkey) region from 3D finite difference method

    NASA Astrophysics Data System (ADS)

    Aochi, Hideo; Ulrich, Thomas; Douglas, John

    2016-04-01

    In the framework of the European project MARSite (2012-2016), one of the main contributions from our research team was to provide ground-motion simulations for the Marmara region from various earthquake source scenarios. We adopted a 3D finite difference code, taking into account the 3D structure around the Sea of Marmara (including the bathymetry) and the sea layer. We simulated two moderate earthquakes (about Mw4.5) and found that the 3D structure improves significantly the waveforms compared to the 1D layer model. Simulations were carried out for different earthquakes (moderate point sources and large finite sources) in order to provide shake maps (Aochi and Ulrich, BSSA, 2015), to study the variability of ground-motion parameters (Douglas & Aochi, BSSA, 2016) as well as to provide synthetic seismograms for the blind inversion tests (Diao et al., GJI, 2016). The results are also planned to be integrated in broadband ground-motion simulations, tsunamis generation and simulations of triggered landslides (in progress by different partners). The simulations are freely shared among the partners via the internet and the visualization of the results is diffused on the project's homepage. All these simulations should be seen as a reference for this region, as they are based on the latest knowledge that obtained during the MARSite project, although their refinement and validation of the model parameters and the simulations are a continuing research task relying on continuing observations. The numerical code used, the models and the simulations are available on demand.

  4. An observational and numerical study of a flash flood event in Eastern Marmara Region.

    NASA Astrophysics Data System (ADS)

    Kahraman, A.

    2010-09-01

    Warm season cut-off cyclones over North-western Anatolia frequently triggers storms with heavy precipitation over Marmara and Western Black Sea Region. Since the area is highly urbanized with a deficiency in substructure, an important percentage of these storms result in flash floods, producing severe damage and fatalities. A heavy precipitation case from 5th to 9th of June, 2010 is studied. With the large scale circulation of the cut-off low, the storm system over Northern Anatolia moved Black Sea, and after getting richer in moisture, turned back to land over Eastern Marmara Region resulting more than 100 mm of precipitation in 24 hours. A peak of 77 mm in 6 hours is observed at Istanbul Sabiha Gokcen Airport on 7th of June, 2010. Damage in some buildings and one death occured related with the flash flood. In addition to synoptic charts, satellite data, surface and upper air observations, numerical simulation with WRF-ARW is used to make a mesoscale analysis of the meteorological conditions. Heavy rain ingredients such as conditionally unstability, low level jet and high moisture exist over the region according to the model output. Precipitable water and storm relative helicity values are mature and CAPE is moderate.

  5. Earthquake and Tsunami Disaster Mitigation in The Marmara Region and Disaster Education in Turkey (SATREPS Project: Science and Technology Research Partnership for Sustainable Development by JICA-JST)

    NASA Astrophysics Data System (ADS)

    Kaneda, Yoshiyuki

    2015-04-01

    Earthquake and Tsunami Disaster Mitigation in The Marmara Region and Disaster Education in Turkey (SATREPS Project: Science and Technology Research Partnership for Sustainable Development by JICA-JST) Yoshiyuki KANEDA Disaster mitigation center Nagoya University/ Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Mustafa ELDIK Boğaziçi University, Kandilli Observatory and       Earthquake Researches Institute (KOERI) and Members of SATREPS Japan-Turkey project The target of this project is the Marmara Sea earthquake after the Izmit (Kocaeli) Earthquake 1999 along to the North Anatolian fault. According to occurrences of historical Earthquakes, epicenters have moved from East to West along to the North Anatolian Fault. There is a seismic gap in the Marmara Sea. In Marmara region, there is Istanbul with high populations such as Tokyo. Therefore, Japan and Turkey can share our own experiences during past damaging earthquakes and we can prepare for future large Earthquakes and Tsunamis in cooperation with each other in SATREPS project. This project is composed of Multidisciplinary research project including observation researches, simulation researches, educational researches, and goals are as follows, ① To develop disaster mitigation policy and strategies based on Multidisciplinary research activities. ② To provide decision makers with newly found knowledge for its implementation to the current regulations. ③ To organize disaster education programs in order to increase disaster awareness in Turkey. ④ To contribute the evaluation of active fault studies in Japan. In this SATREPS project, we will integrate Multidisciplinary research results for disaster mitigation in Marmara region and .disaster education in Turkey.

  6. Biogenic sulphur emissions and inferred non-sea-salt-sulphate cloud condensation nuclei in and around Antarctica

    NASA Astrophysics Data System (ADS)

    O'Dowd, Colin D.; Lowe, Jason A.; Smith, Michael H.; Davison, Brian; Hewitt, C. Nicholas; Harrison, Roy M.

    1997-06-01

    Accumulation mode aerosol properties and biogenic sulphur emissions over the South Atlantic and Antarctic Oceans are examined. Two contrasting air masses, polar and maritime, each possessing distinct aerosol properties, were encountered during the summer months. By examining aerosol volatile properties, polar air masses arriving from the Antarctic continent were shown to consist primarily Of H2SO4 in the accumulation mode size range, with inferred NH+4 to SO=4 molar ratios close to zero. By comparison, air masses of temperate maritime origin were significantly neutralized with molar ratios of ≈1. These results suggest a deficit of ammonia in polar air masses compared with that in maritime air masses. Dimethyl sulphide (DMS) exhibited no correlation with its putative aerosol oxidation products, although spatial coherence in atmospheric concentrations of DMS, methane sulphonic acid (MSA), and non-sea-salt (nss)-sulphate mass was observed. Volatility analysis, used to infer nss-sulphate cloud condensation nuclei (nss-sCCN) active at a supersaturation of ≈0.2%, indicates that nss-sCCN mass and number concentration were best correlated with MSA mass (r≈0.63). Aerosol volatility identified the presence of MSA in submicron non-sea-salt aerosol; however, its contribution to the aerosol mass was small relative to the contribution of sulphuric acid and ammonium bisulphate/sulphate aerosol. The marine sulphur cycle appears strongly coupled to the sea-salt cycle with, typically, 80-90% of nss-sulphate thought to be internally mixed with sea-salt aerosol. During the austral Summer of 1992/1993, a period of strong biological productivity in the Weddell Sea and sub-Antarctic Ocean, particularly during ice-melt, the cruise-average DMS flux of 61 μg m-2 d-1 corresponded to a very modest average nss-sCCN concentration of 21 cm-3. Observed peak values of DMS flux and inferred nss-CCN concentrations during the cruise were 477 μg m-2 d-1 and 64 cm-3, respectively. Events of new

  7. Holocene seasonal sea-surface temperature variations in the southern Adriatic Sea inferred from a multiproxy approach

    NASA Astrophysics Data System (ADS)

    Sangiorgi, Francesca; Capotondi, Lucilla; Combourieu Nebout, Nathalie; Vigliotti, Luigi; Brinkhuis, Henk; Giunta, Simona; Lotter, Andrè F.; Morigi, Caterina; Negri, Alessandra; Reichart, Gert-Jan

    2003-12-01

    Holocene cooling events have been reconstructed for the southern Adriatic Sea (central Mediterranean) by means of analyses of organic walled dinoflagellate cysts, planktonic foraminifera, oxygen isotopes, calcareous nanoplankton, alkenones and pollen from a sediment core. Two cooling events have been detected, during which sea-surface temperatures (SSTs) were ca. 2°C lower. Unravelling the SST signal into dominant seasonal components suggests maximum winter cooling of 2°C at around 6.0 ka, whereas the cooling at ca. 3.0 ka might be the result of a spring temperature cooling of 2-3°C. The events, lasting several hundred years, are apparently synchronous with those in the Aegean Sea, where they have been related to known cooling events from the Greenland ice-core record. A distinct interruption in Adriatic Sea sapropel S1 is not clearly accompanied by a local drop in winter temperatures, but seems to be forced by ventilation, which probably occurred earlier in the Aegean Sea and was subsequently transmitted to the Adriatic Sea. Copyright

  8. Towards Integrated Marmara Strong Motion Network

    NASA Astrophysics Data System (ADS)

    Durukal, E.; Erdik, M.; Safak, E.; Ansal, A.; Ozel, O.; Alcik, H.; Mert, A.; Kafadar, N.; Korkmaz, A.; Kurtulus, A.

    2009-04-01

    Istanbul has a 65% chance of having a magnitude 7 or above earthquake within the next 30 years. As part of the preparations for the future earthquake, strong motion networks have been installed in and around Istanbul. The Marmara Strong Motion Network, operated by the Department of Earthquake Engineering of Kandilli Observatory and Earthquake Research Institute, encompasses permanent systems outlined below. It is envisaged that the networks will be run by a single entity responsible for technical management and maintanence, as well as for data management, archiving and dissemination through dedicated web-based interfaces. • Istanbul Earthquake Rapid Response and Early Warning System - IERREWS (one hundred 18-bit accelerometers for rapid response; ten 24-bit accelerometers for early warning) • IGDAŞ Gas Shutoff Network (100 accelerometers to be installed in 2010 and integrated with IERREWS) • Structural Monitoring Arrays - Fatih Sultan Mehmet Suspension Bridge (1200m-long suspension bridge across the Bosphorus, five 3-component accelerometers + GPS sensors) - Hagia Sophia Array (1500-year-old historical edifice, 9 accelerometers) - Süleymaniye Mosque Array (450-year-old historical edifice,9 accelerometers) - Fatih Mosque Array (237-year-old historical edifice, 9 accelerometers) - Kanyon Building Array (high-rise office building, 5 accelerometers) - Isbank Tower Array (high-rise office building, 5 accelerometers) - ENRON Array (power generation facility, 4 acelerometers) - Mihrimah Sultan Mosque Array (450-year-old historical edifice,9 accelerometers + tiltmeters, to be installed in 2009) - Sultanahmet Mosque Array, (390-year-old historical edifice, 9 accelerometers + tiltmeters, to be installed in 2009) • Special Arrays - Atakoy Vertical Array (four 3-component accelerometers at 25, 50, 75, and 150 m depths) - Marmara Tube Tunnel (1400 m long submerged tunnel, 128 ch. accelerometric data, 24 ch. strain data, to be installed in 2010) - Air-Force Academy

  9. Back-arc Mantle Evolution inferred from Peridotite Xenotlishs from the Japan Sea

    NASA Astrophysics Data System (ADS)

    Morishita, T.; Ichiyama, Y.; Tamura, A.; Arai, S.

    2014-12-01

    Peridotite xenoliths are recovered in basaltic to andesitic lavas from several localities in the Japan Sea, a Miocene back-arc basin of the Western Pacific region. These peridotites are classified into two groups: two-pyroxene peridotitess and dunite-wehrlite groups. Although slight chemical modifications are observed in these peridotite samples, two-pyroxene peridotite group has retained their original residual mantle geochemical signatures left after partial melting. The dunite-wehrlite group is, on the other hand, probably formed by extensive interaction of the two-pyroxene peridotite group. We examined trace element characteristics of clinopyroxene in these xenoliths. Light REE-depleted clinopyroxenes that are usually interpreted as a simple residual mantle after anhydrous partial melting are similar to those of abyssal peridotite recovered from mid-ocean ridges and back-arc basins. Other samples show LREE-enriched patterns that are residues after influx melting caused by hydrous melt/supercritical fluids released from the subducted slab at high pressure conditions. The geotectonic and geochemical variations of the peridotite xenoliths from the Japan Sea (Shirabeshi Seamount, Seifu Seamount and Oshima-Oshima Island) suggest that the mantle beneath the Japan Sea are suffered from hydrous to anhydrous melting as the Japan Sea forms. This is consistent with the geochemical and isotopic results from Miocene basaltic rocks formed during opening of the Japan Sea (Sato et al., Jour. Petrol., 2013). The Japan Sea peridotite xenoliths also shed lights on the origin of ophiolites.

  10. Thin Sea-Ice Thickness as Inferred from Passive Microwave and In Situ Observations

    NASA Technical Reports Server (NTRS)

    Naoki, Kazuhiro; Ukita, Jinro; Nishio, Fumihiko; Nakayama, Masashige; Comiso, Josefino C.; Gasiewski, Al

    2007-01-01

    Since microwave radiometric signals from sea-ice strongly reflect physical conditions of a layer near the ice surface, a relationship of brightness temperature with thickness is possible especially during the early stages of ice growth. Sea ice is most saline during formation stage and as the salinity decreases with time while at the same time the thickness of the sea ice increases, a corresponding change in the dielectric properties and hence the brightness temperature may occur. This study examines the extent to which the relationships of thickness with brightness temperature (and with emissivity) hold for thin sea-ice, approximately less than 0.2 -0.3 m, using near concurrent measurements of sea-ice thickness in the Sea of Okhotsk from a ship and passive microwave brightness temperature data from an over-flying aircraft. The results show that the brightness temperature and emissivity increase with ice thickness for the frequency range of 10-37 GHz. The relationship is more pronounced at lower frequencies and at the horizontal polarization. We also established an empirical relationship between ice thickness and salinity in the layer near the ice surface from a field experiment, which qualitatively support the idea that changes in the near-surface brine characteristics contribute to the observed thickness-brightness temperature/emissivity relationship. Our results suggest that for thin ice, passive microwave radiometric signals contain, ice thickness information which can be utilized in polar process studies.

  11. Constraining coastal change: A morpho-sedimentological concept to infer sea-level oscillation

    NASA Astrophysics Data System (ADS)

    Mauz, Barbara; Shen, Zhixiong

    2016-04-01

    One of the responders to Milankovitch-scale climate changes is sea level which, in turn, is a driver of coastal change. In literature, the sedimentary sequences representing the coastal change are often linked to high sea-level stands, to intermediate sea-level positions or to regressive shorelines. We note apparent contradictions that indicate a lack of concept and inconsistent usage of sea level-related terms. To overcome this, we combine an integrated morpho-sedimentological concept for microtidal, mid-latitudinal coasts with chronologies based on Bayesian statistics. The concept regards the coastal sedimentary system as a depositional complex consisting of shallow-marine, aeolian and alluvial facies. These facies are in juxtaposition and respond simultaneously to external forcing. Bayesian statistics constrains the timing of the sequence based on optical or radiocarbon ages. Here, we present the site Hergla located on the North African coast of the central Mediterranean Sea as a case study to illustrate how the approach helps eliminating contradictions. The site has been cited frequently for confirming the hypothesis of a global two peak sea-level highstand during the last interglacial (MIS 5e). The ~2 km cliff exposure at Hergla was surveyed, mapped, logged and sampled for further describing the sediments and their depositional environment through thin section and Bayesian modelling of optical ages. Using our concept based on sequence stratigraphy tools, the section is interpreted as representing a coastal barrier with two bounding surfaces in the succession. Both surfaces mark the falling sea level of, first, MIS 5e and, second, MIS 5a and hence bound the falling stage system tract of a forced regression. Part of the deposits between the two surfaces are pulled up onto the shoulder of a small rising horst and the associated tectonic event coincided with the MIS 5a sea-level rise enhancing locally the accommodation space for a second foreshore environment. Our

  12. Tectonic evolution of the Salton Sea inferred from seismic reflection data

    USGS Publications Warehouse

    Brothers, D.S.; Driscoll, N.W.; Kent, G.M.; Harding, A.J.; Babcock, J.M.; Baskin, R.L.

    2009-01-01

    Oblique extension across strike-slip faults causes subsidence and leads to the formation of pull-apart basins such as the Salton Sea in southern California. The formation of these basins has generally been studied using laboratory experiments or numerical models. Here we combine seismic reflection data and geological observations from the Salton Sea to understand the evolution of this nascent pull-apart basin. Our data reveal the presence of a northeast-trending hinge zone that separates the sea into northern and southern sub-basins. Differential subsidence (10 mm yr 1) in the southern sub-basin suggests the existence of northwest-dipping basin-bounding faults near the southern shoreline, which may control the spatial distribution of young volcanism. Rotated and truncated strata north of the hinge zone suggest that the onset of extension associated with this pull-apart basin began after 0.5 million years ago. We suggest that slip is partitioned spatially and temporally into vertical and horizontal domains in the Salton Sea. In contrast to previous models based on historical seismicity patterns, the rapid subsidence and fault architecture that we document in the southern part of the sea are consistent with experimental models for pull-apart basins. ?? 2009 Macmillan Publishers Limited.

  13. Holocene sea level and climate change in the Black Sea: Multiple marine incursions related to freshwater discharge events

    USGS Publications Warehouse

    Martin, R.E.; Leorri, E.; McLaughlin, P.P.

    2007-01-01

    Repeated marine invasions of the Black Sea during the Holocene have been inferred by many eastern scientists as resulting from episodes of marine inflow from the Mediterranean beneath a brackish outflow from the Black Sea. We support this scenario but a fundamental question remains: What caused the repeated marine invasions? We offer an hypothesis for the repeated marine invasions of the Black Sea based on: (1) the overall similarity of sea-level curves from both tectonically quiescent and active margins of the Black Sea and their similarity to a sequence stratigraphic record from the US mid-Atlantic coast. The similarity of the records from two widely-separated regions suggests their common response to documented Holocene climate ocean-atmosphere reorganizations (coolings); (2) the fact that in the modern Black Sea, freshwater runoff from surrounding rivers dominates over evaporation, so that excess runoff might have temporarily raised Black Sea level (although the Black Sea would have remained brackish). Following the initial invasion of the Black Sea by marine Mediterranean waters (through the Marmara Sea) in the early Holocene, repeated marine incursions were modulated, or perhaps even caused, by freshwater discharge to the Black Sea. Climatic amelioration (warming) following each documented ocean-atmosphere reorganization during the Holocene likely shifted precipitation patterns in the surrounding region and caused mountain glaciers to retreat, increasing freshwater runoff above modern values and temporarily contributing to an increase of Black Sea level. Freshwater-to-brackish water discharges into the Black Sea initially slowed marine inflow but upon mixing of runoff with more marine waters beneath them and their eventual exit through the Bosphorus, marine inflow increased again, accounting for the repeated marine invasions. The magnitude of the hydrologic and sea-level fluctuations became increasingly attenuated through the Holocene, as reflected by Black

  14. Subglacial hydraulic conditions of the former Barents Sea Ice Sheet inferred from meltwater landforms

    NASA Astrophysics Data System (ADS)

    Shackleton, Calvin; Bjarnadóttir, Lilja; Winsborrow, Monica; Esteves, Mariana; Andreassen, Karin

    2016-04-01

    A large multibeam dataset acquired by the MAREANO programme covering over 24,000 km2 at 5 m horizontal resolution has uncovered abundant subglacial meltwater landforms in the central Barents Sea. These landforms provide unprecedented insights into the nature of hydrological systems operating at the bed of the former Barents Sea Ice Sheet, helping us to understand the subglacial environments of marine based ice sheets as a whole. Large sinuous features up to 3.5 km wide and over 40 km long, with depths up to 40 m are interpreted as braided tunnel valleys, which would have drained vast amounts of water at the base of the ice sheet. Dendritic channels are also common, up to 42 km long and 24 m deep, along with several anastomosing channels and numerous complex esker systems. These features document that a wide range of subglacial hydraulic conditions and a well-established meltwater system existed beneath the former Barents Sea Ice Sheet. In conjunction with mapping of glacial landforms, these meltwater features provide the basis for a reconstruction of the subglacial drainage systems in the central Barents Sea and their interaction with the dynamic activity of the overlying ice sheet.

  15. Changes in the hydrochemistry of the Black Sea inferred from water density profiles

    NASA Astrophysics Data System (ADS)

    Tugrul, Suleyman; Basturk, Ozden; Saydam, Cemal; Yilmaz, Aysen

    1992-09-01

    DURING the past two decades, catastrophic changes have occurred in the Black Sea ecosystem: the influx of pollution from the major rivers has caused intense eutrophication at the northwest coastal margin1, and fish stocks have collapsed throughout the sea2. The hydrochemical details of these events are still poorly understood3-7, and a way needs to be found to distinguish long-term variations from short-term natural fluctuations3,4 if future management of the Black Sea ecosystem is to be successful. We show here that a coherent description may be achieved by analysing the hydro-chemical data as a function of water density rather than depth. Our findings suggest that, contrary to the suggestion of Murray et al.3, the upper boundary of the low-lying anoxic waters has remained stationary since 1969, whereas the intermediate suboxic zone has enlarged, reducing the overall depth of the oxygenated upper waters by ~20 m. Moreover, a long-term increase in the nitrate concentration and a concomitant decrease in the silicate and ammonia concentrations in this upper layer are indicative of the considerable changes taking place in the biochemical regime of the Black Sea.

  16. Variation in winter diet of southern Beaufort Sea polar bears inferred from stable isotope analysis

    USGS Publications Warehouse

    Bentzen, T.W.; Follmann, E.H.; Amstrup, Steven C.; York, G.S.; Wooller, M.J.; O'Hara, T. M.

    2007-01-01

    Ringed seals (Phoca hispida Schreber, 1775 = Pusa hispida (Schreber, 1775)) and bearded seals (Erignathus barbatus (Erxleben, 1777)) represent the majority of the polar bear (Ursus maritimus Phipps, 1774) annual diet. However, remains of lower trophic level bowhead whales (Balaena mysticetus L., 1758) are available in the southern Beaufort Sea and their dietary contribution to polar bears has been unknown. We used stable isotope (13C/12C, δ13C, 15N/14N, and δ15N) analysis to determine the diet composition of polar bears sampled along Alaska’s Beaufort Sea coast in March and April 2003 and 2004. The mean δ15N values of polar bear blood cells were 19.5‰ (SD = 0.7‰) in 2003 and 19.9‰ (SD = 0.7‰) in 2004. Mixing models indicated bowhead whales composed 11%–26% (95% CI) of the diets of sampled polar bears in 2003, and 0%–14% (95% CI) in 2004. This suggests significant variability in the proportion of lower trophic level prey in polar bear diets among individuals and between years. Polar bears depend on sea ice for hunting seals, and the temporal and spatial availabilities of sea ice are projected to decline. Consumption of low trophic level foods documented here suggests bears may increasingly scavenge such foods in the future.

  17. Central Asian sand seas climate change as inferred from OSL dating

    NASA Astrophysics Data System (ADS)

    Maman, Shimrit; Tsoar, Haim; Blumberg, Dan; Porat, Naomi

    2014-05-01

    Luminescence dating techniques have become more accessible, widespread, more accurate and support studies of climate change. Optically stimulated luminescence (OSL) is used to determine the time elapsed since quartz grains were last exposed to sunlight, before they were buried and the dune stabilized. Many sand seas have been dated extensively by luminescence, e.g., the Kalahari, Namib the Australian linear dunes and the northwestern Negev dune field, Israel. However, no ages were published so far from the central Asian sand seas. The lack of dune stratigraphy and numerical ages precluded any reliable assessment of the paleoclimatic significance of dunes in central Asia. Central Asian Sand seas (ergs) have accumulated in the Turan basin, north-west of the Hindu Kush range, and span from south Turkmenistan to the Syr-Darya River in Kazakhstan. These ergs are dissected by the Amu-Darya River; to its north lies the Kyzylkum (red sands) and to its south lies the Karakum (black sands). Combined, they form one of the largest sand seas in the world. This area is understudied, and little information has been published regarding the sands stabilization processes and deposition ages. In this study, OSL ages for the Karakum and Kyzylkum sands are presented and analysis of the implications of these results is provided. Optical dates obtained in this study are used to study the effects climatic changes had on the mobility and stability of the central Asian sand seas. Optically stimulated luminescence ages derived from the upper meter of the interdune of 14 exposed sections from both ergs, indicate extensive sand and dune stabilization during the mid-Holocene. This stabilization is understood to reflect a transition to a warmer, wetter, and less windy climate that generally persisted until today. The OSL ages, coupled with a compilation of regional paleoclimatic data, corroborate and reinforce the previously proposed Mid-Holocene Liavliakan phase, known to reflect a warmer

  18. Ice shelves in the Pleistocene Arctic Ocean inferred from glaciogenic deep-sea bedforms.

    PubMed

    Polyak, L; Edwards, M H; Coakley, B J; Jakobsson, M

    2001-03-22

    It has been proposed that during Pleistocene glaciations, an ice cap of 1 kilometre or greater thickness covered the Arctic Ocean. This notion contrasts with the prevailing view that the Arctic Ocean was covered only by perennial sea ice with scattered icebergs. Detailed mapping of the ocean floor is the best means to resolve this issue. Although sea-floor imagery has been used to reconstruct the glacial history of the Antarctic shelf, little data have been collected in the Arctic Ocean because of operational constraints. The use of a geophysical mapping system during the submarine SCICEX expedition in 1999 provided the opportunity to perform such an investigation over a large portion of the Arctic Ocean. Here we analyse backscatter images and sub-bottom profiler records obtained during this expedition from depths as great as 1 kilometre. These records show multiple bedforms indicative of glacial scouring and moulding of sea floor, combined with large-scale erosion of submarine ridge crests. These distinct glaciogenic features demonstrate that immense, Antarctic-type ice shelves up to 1 kilometre thick and hundreds of kilometres long existed in the Arctic Ocean during Pleistocene glaciations.

  19. Nitrous oxide cycling in the Black Sea inferred from stable isotope and isotopomer distributions

    NASA Astrophysics Data System (ADS)

    Westley, Marian B.; Yamagishi, Hiroaki; Popp, Brian N.; Yoshida, Naohiro

    2006-08-01

    The low-oxygen regions of the world's oceans have been shown to be major sources of nitrous oxide, a trace gas in the atmosphere that contributes to both greenhouse warming and the destruction of stratospheric ozone. Nitrous oxide can be produced as a by-product of nitrification or an intermediate of denitrification; low oxygen conditions enhance the yield of nitrous oxide from both pathways. We measured the concentration and isotopic composition of dissolved nitrous oxide at several stations in the Black Sea, an anoxic basin with a well-defined suboxic layer that separates the ventilated surface waters from the sulfidic deep waters. Our data show that in contrast to other low-oxygen marine regions, nitrous oxide does not accumulate in the Black Sea at significant levels. Moreover, whereas the reduction of nitrous oxide by denitrification usually yields residual gas that is enriched in both stable isotopes, in the Black Sea declining nitrous oxide concentrations are accompanied by enrichment in 18O-N 2O but depletion in 15N-N 2O. We measured a minimum δ15N-N 2O value of -10.8±0.8‰ vs. air N 2, by far the lowest measured to date for seawater. Measurements of the distribution of 15N within the linear nitrous oxide molecule reveal that this unusual isotopic signal is most pronounced in the end-position nitrogen, and that site preference, or the tendency for 15N to be found in the center-position nitrogen, co-varies positively with 18O-N 2O. We surmise that the highly unusual isotopic composition of Black Sea nitrous oxide is the result of two processes: production of 15N-depleted nitrous oxide by ammonium oxidation followed by its reduction by denitrification, which causes enrichment in 18O and enhancement of 15N-site preference. Bottle incubation experiments with 15N-ammonium and 15N-nitrite reveal that both oxidation and reduction pathways to nitrous oxide are active in the Black Sea suboxic zone.

  20. Ocean Winds and Turbulent Air-Sea Fluxes Inferred From Remote Sensing

    NASA Technical Reports Server (NTRS)

    Bourassa, Mark A.; Gille, Sarah T.; Jackson, Daren L.; Roberts, J. Brent; Wick, Gary A.

    2010-01-01

    Air-sea turbulent fluxes determine the exchange of momentum, heat, freshwater, and gas between the atmosphere and ocean. These exchange processes are critical to a broad range of research questions spanning length scales from meters to thousands of kilometers and time scales from hours to decades. Examples are discussed (section 2). The estimation of surface turbulent fluxes from satellite is challenging and fraught with considerable errors (section 3); however, recent developments in retrievals (section 3) will greatly reduce these errors. Goals for the future observing system are summarized in section 4. Surface fluxes are defined as the rate per unit area at which something (e.g., momentum, energy, moisture, or CO Z ) is transferred across the air/sea interface. Wind- and buoyancy-driven surface fluxes are called surface turbulent fluxes because the mixing and transport are due to turbulence. Examples of nonturbulent processes are radiative fluxes (e.g., solar radiation) and precipitation (Schmitt et al., 2010). Turbulent fluxes are strongly dependent on wind speed; therefore, observations of wind speed are critical for the calculation of all turbulent surface fluxes. Wind stress, the vertical transport of horizontal momentum, also depends on wind direction. Stress is very important for many ocean processes, including upper ocean currents (Dohan and Maximenko, 2010) and deep ocean currents (Lee et al., 2010). On short time scales, this horizontal transport is usually small compared to surface fluxes. For long-term processes, transport can be very important but again is usually small compared to surface fluxes.

  1. Descent toward the Icehouse: Eocene sea surface cooling inferred from GDGT distributions

    NASA Astrophysics Data System (ADS)

    Inglis, Gordon N.; Farnsworth, Alexander; Lunt, Daniel; Foster, Gavin L.; Hollis, Christopher J.; Pagani, Mark; Jardine, Phillip E.; Pearson, Paul N.; Markwick, Paul; Galsworthy, Amanda M. J.; Raynham, Lauren; Taylor, Kyle. W. R.; Pancost, Richard D.

    2015-07-01

    The TEX86 proxy, based on the distribution of marine isoprenoidal glycerol dialkyl glycerol tetraether lipids (GDGTs), is increasingly used to reconstruct sea surface temperature (SST) during the Eocene epoch (56.0-33.9 Ma). Here we compile published TEX86 records, critically reevaluate them in light of new understandings in TEX86 palaeothermometry, and supplement them with new data in order to evaluate long-term temperature trends in the Eocene. We investigate the effect of archaea other than marine Thaumarchaeota upon TEX86 values using the branched-to-isoprenoid tetraether index (BIT), the abundance of GDGT-0 relative to crenarchaeol (%GDGT-0), and the Methane Index (MI). We also introduce a new ratio, %GDGTRS, which may help identify Red Sea-type GDGT distributions in the geological record. Using the offset between TEX86H and TEX86L (ΔH-L) and the ratio between GDGT-2 and GDGT-3 ([2]/[3]), we evaluate different TEX86 calibrations and present the first integrated SST compilation for the Eocene (55 to 34 Ma). Although the available data are still sparse some geographic trends can now be resolved. In the high latitudes (>55°), there was substantial cooling during the Eocene (~6°C). Our compiled record also indicates tropical cooling of ~2.5°C during the same interval. Using an ensemble of climate model simulations that span the Eocene, our results indicate that only a small percentage (~10%) of the reconstructed temperature change can be ascribed to ocean gateway reorganization or paleogeographic change. Collectively, this indicates that atmospheric carbon dioxide (pCO2) was the likely driver of surface water cooling during the descent toward the icehouse.

  2. Eolian depositional phases during the past 50 ka and inferred climate variability for the Pampean Sand Sea, western Pampas, Argentina

    NASA Astrophysics Data System (ADS)

    Tripaldi, Alfonsina; Forman, Steven L.

    2016-05-01

    The Pampean Sand Sea, which occurs from the Argentinian Pampas to the eastern Andean piedmont, hosts presently stabilized dune fields spanning the late Quaternary. This study integrates previous results and presents new geomorphic, stratigraphic, sedimentological, and chronologic data for nineteen >2 m-thick eolian successions for the San Luis paleo-dune field, western Pampas, to better constrain the depositional history. Six eolian depositional phases are identified spanning the past 50 ka, interposed with paleosols and/or bounded by erosive surfaces. Age control was from 61 OSL ages of small aliquots of quartz grains from eolian stratigraphic units. The inferred timing of eolian phases are at ca. 70 ± 10 yr, 190 ± 20 yr, 12 to 1 ka, 22 to 17 ka, 29 to 24 ka, and 40 to 32 ka. A maximum span for periods of pedogenesis at ca. 12 to 17 ka, 22 to 24 ka, and 29 to 32 ka was provided by bounding OSL ages, which broadly overlap with high stands of pluvial lakes and glacier advances in the central Andes. We infer that the added precipitation may reflect expansion of the Southern Hemisphere monsoon, associated with Northern Hemisphere Heinrich events, leading to episodes of significantly wetter conditions (>350 mm MAP) to at least 35° S. Most of the Holocene (12 ka to 0.8 ka) was characterized by sand sheet deposit under drier than present conditions (100-450 mm MAP), associated with Monte-type vegetation (shrub steppe). The latest two eolian depositional phases, occurred at ca. 190 and 70 yr ago, during the historic period with European settlement and are related to anthropogenic landscape disturbance, though the youngest phase was concomitant with 1930s drought. Wet conditions dominated since ca. AD 1970 with new lakes and rivers forming across this eolian terrain; an incongruous environmental response in reference to drier conditions for most of the Holocene.

  3. Boundary-layer mantle flow under the Dead Sea transform fault inferred from seismic anisotropy.

    PubMed

    Rümpker, Georg; Ryberg, Trond; Bock, Günter

    2003-10-02

    Lithospheric-scale transform faults play an important role in the dynamics of global plate motion. Near-surface deformation fields for such faults are relatively well documented by satellite geodesy, strain measurements and earthquake source studies, and deeper crustal structure has been imaged by seismic profiling. Relatively little is known, however, about deformation taking place in the subcrustal lithosphere--that is, the width and depth of the region associated with the deformation, the transition between deformed and undeformed lithosphere and the interaction between lithospheric and asthenospheric mantle flow at the plate boundary. Here we present evidence for a narrow, approximately 20-km-wide, subcrustal anisotropic zone of fault-parallel mineral alignment beneath the Dead Sea transform, obtained from an inversion of shear-wave splitting observations along a dense receiver profile. The geometry of this zone and the contrast between distinct anisotropic domains suggest subhorizontal mantle flow within a vertical boundary layer that extends through the entire lithosphere and accommodates the transform motion between the African and Arabian plates within this relatively narrow zone.

  4. Acoustic and optical methods to infer water transparency at Time Series Station Spiekeroog, Wadden Sea

    NASA Astrophysics Data System (ADS)

    Schulz, Anne-Christin; Badewien, Thomas H.; Garaba, Shungudzemwoyo P.; Zielinski, Oliver

    2016-11-01

    Water transparency is a primary indicator of optical water quality that is driven by suspended particulate and dissolved material. A data set from the operational Time Series Station Spiekeroog located at a tidal inlet of the Wadden Sea was used to perform (i) an inter-comparison of observations related to water transparency, (ii) correlation tests among these measured parameters, and (iii) to explore the utility of both acoustic and optical tools in monitoring water transparency. An Acoustic Doppler Current Profiler was used to derive the backscatter signal in the water column. Optical observations were collected using above-water hyperspectral radiometers and a submerged turbidity metre. Bio-fouling on the turbidity sensors optical windows resulted in measurement drift and abnormal values during quality control steps. We observed significant correlations between turbidity collected by the submerged metre and that derived from above-water radiometer observations. Turbidity from these sensors was also associated with the backscatter signal derived from the acoustic measurements. These findings suggest that both optical and acoustic measurements can be reasonable proxies of water transparency with the potential to mitigate gaps and increase data quality in long-time observation of marine environments.

  5. Mitochondrial DNA in the sea urchin Arbacia lixula: evolutionary inferences from nucleotide sequence analysis.

    PubMed

    De Giorgi, C; Lanave, C; Musci, M D; Saccone, C

    1991-07-01

    From the stirodont Arbacia lixula we determined the sequence of 5,127 nucleotides of mitochondrial DNA (mtDNA) encompassing 18 tRNAs, two complete coding genes, parts of three other coding genes, and part of the 12S ribosomal RNA (rRNA). The sequence confirms that the organization of mtDNA is conserved within echinoids. Furthermore, it underlines the following peculiar features of sea urchin mtDNA: the clustering of tRNAs, the short noncoding regulatory sequence, and the separation by the ND1 and ND2 genes of the two rRNA genes. Comparison with the orthologous sequences from the camarodont species Paracentrotus lividus and Strongylocentrotus purpuratus revealed that (1) echinoids have an extra piece on the amino terminus of the ND5 gene that is probably the remnant of an old leucine tRNA gene; (2) third-position codon nucleotide usage has diverged between A. lixula and the camarodont species to a significant extent, implying different directional mutational pressures; and (3) the stirodont-camarodont divergence occurred twice as long ago as did the P. lividus-S. purpuratus divergence.

  6. Sea ice motions in the Central Arctic pack ice as inferred from AVHRR imagery

    NASA Technical Reports Server (NTRS)

    Emery, William; Maslanik, James; Fowler, Charles

    1995-01-01

    Synoptic observations of ice motion in the Arctic Basin are currently limited to those acquired by drifting buoys and, more recently, radar data from ERS-1. Buoys are not uniformly distributed throughout the Arctic, and SAR coverage is currently limited regionally and temporally due to the data volume, swath width, processing requirements, and power needs of the SAR. Additional ice-motion observations that can map ice responses simultaneously over large portions of the Arctic on daily to weekly time intervals are thus needed to augment the SAR and buoys data and to provide an intermediate-scale measure of ice drift suitable for climatological analyses and ice modeling. Principal objectives of this project were to: (1) demonstrate whether sufficient ice features and ice motion existed within the consolidated ice pack to permit motion tracking using AVHRR imagery; (2) determine the limits imposed on AVHRR mapping by cloud cover; and (3) test the applicability of AVHRR-derived motions in studies of ice-atmosphere interactions. Each of these main objectives was addressed. We conclude that AVHRR data, particularly when blended with other available observations, provide a valuable data set for studying sea ice processes. In a follow-on project, we are now extending this work to cover larger areas and to address science questions in more detail.

  7. Mesozooplankton Grazing on Picocyanobacteria in the Baltic Sea as Inferred from Molecular Diet Analysis

    PubMed Central

    Motwani, Nisha H.; Gorokhova, Elena

    2013-01-01

    Our current knowledge on the microbial component of zooplankton diet is limited, and it is generally assumed that bacteria-sized prey is not directly consumed by most mesozooplankton grazers in the marine food webs. We questioned this assumption and conducted field and laboratory studies to examine picocyanobacteria contribution to the diets of Baltic Sea zooplankton, including copepods. First, qPCR targeting ITS-1 rDNA sequence of the picocyanobacteria Synechococcus spp. was used to examine picocyanobacterial DNA occurrence in the guts of Baltic zooplankton (copepods, cladocerans and rotifers). All field-collected zooplankton were found to consume picocyanobacteria in substantial quantities. In terms of Synechococcus quantity, the individual gut content was highest in cladocerans, whereas biomass-specific gut content was highest in rotifers and copepod nauplii. Moreover, the gut content in copepods was positively related to the picocyanobacteria abundance and negatively to the total phytoplankton abundance in the water column at the time of sampling. This indicates that increased availability of picocyanobacteria resulted in the increased intake of this prey and that copepods may rely more on picoplankton when food in the preferred size range declines. Second, a feeding experiments with a laboratory reared copepod Acartia tonsa fed a mixture of the picocyanobacterium Synechococcus bacillaris and microalga Rhodomonas salina confirmed that copepods ingested Synechococcus, even when the alternative food was plentiful. Finally, palatability of the picocyanobacteria for A. tonsa was demonstrated using uptake of 13C by the copepods as a proxy for carbon uptake in feeding experiment with 13C-labeled S. bacillaris. These findings suggest that, if abundant, picoplankton may become an important component of mesozooplankton diet, which needs to be accounted for in food web models and productivity assessments. PMID:24260175

  8. Assessing Natural Hazard Vulnerability Through Marmara Region Using GIS

    NASA Astrophysics Data System (ADS)

    Sabuncu, A.; Garagon Dogru, A.; Ozener, H.

    2013-12-01

    Natural hazards are natural phenomenon occured in the Earth's system that include geological and meteorological events such as earthquakes, floods, landslides, droughts, fires and tsunamis. The metropolitan cities are vulnerable to natural hazards due to their population densities, industrial facilities and proporties. The urban layout of the megacities are complex since industrial facilities are interference with residential area. The Marmara region is placed in North-western Turkey suffered from natural hazards (earthquakes, floods etc.) for years. After 1999 Kocaeli and Duzce earthquakes and 2009 Istanbul flash floods, dramatic number of casualities and economic losses were reported by the authorities. Geographic information systems (GIS) have substantial capacity in order to develop natural disaster management. As these systems provide more efficient and reliable analysis and evaluation of the data in the management, and also convenient and better solutions for the decision making before during and after the natural hazards. The Earth science data and socio-economic data can be integrated into a GIS as different layers. Additionally, satellite data are used to understand the changes pre and post the natural hazards. GIS is a powerful software for the combination of different type of digital data. A natural hazard database for the Marmara region provides all different types of digital data to the users. All proper data collection processing and analysing are critical to evaluate and identify hazards. The natural hazard database allows users to monitor, analyze and query past and recent disasters in the Marmara Region. The long term aim of this study is to develop geodatabase and identify the natural hazard vulnerabilities of the metropolitan cities.

  9. Earthquake and Tsunami Disaster Mitigation in The Marmara Region and Disaster Education in Turkey Part2 Yoshiyuki KANEDA Nagoya University Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Haluk OZENER Boğaziçi University, Earthquake Researches Institute (KOERI) and Members of SATREPS Japan-Turkey project

    NASA Astrophysics Data System (ADS)

    Kaneda, Y.; Ozener, H.

    2015-12-01

    The 1999 Izumit Earthquake as the destructive earthquake occurred near the Marmara Sea. The Marmara Sea should be focused on because of a seismic gap in the North Anatolian fault. Istanbul is located around the Marmara Sea, so, if next earthquake will occur near Istanbul, fatal damages will be generated. The Japan and Turkey can share our own experiences during past damaging earthquakes and we can prepare for future large earthquakes in cooperation with each other. In earthquakes in Tokyo area and Istanbul area as the destructive earthquakes near high population cities, there are common disaster researches and measures. For disaster mitigation, we are progressing multidisciplinary researches. Our goals of this SATREPS project are as follows, To develop disaster mitigation policy and strategies based on multidisciplinary research activities. To provide decision makers with newly found knowledge for its implementation to the current regulations. To organize disaster education programs in order to increase disaster awareness in Turkey. To contribute the evaluation of active fault studies in Japan. This project is composed of four research groups. The first group is Marmara Earthquake Source region observationally research group. This group has 4 sub-themes such as Seismicity, Geodesy, Electromagnetics and Trench analyses. The second group focuses on scenario researches of earthquake occurrence along the North Anatolia fault and precise tsunami simulation in the Marmara region. Aims of the third group are improvements and constructions of seismic characterizations and damage predictions based on observation researches and precise simulations. The fourth group is promoting disaster educations using research result visuals. In this SATREPS project, we will integrate these research results for disaster mitigation in Marmara region and .disaster education in Turkey. We will have a presentation of the updated results of this SATREPS project.

  10. Three Kanto Earthquakes Inferred from the Tsunami Deposits and the Relative Sea Level Change in the Miura Peninsula, Central Japan

    NASA Astrophysics Data System (ADS)

    Kim, H.; Shimazaki, K.; Chiba, T.; Ishibe, T.; Okamura, M.; Matsuoka, H.; Tsuji, Y.; Satake, K.

    2010-12-01

    The Kanto earthquake is a great interplate earthquake caused by subduction of the Philippine Sea Plate beneath the Japan Island along the Sagami Trough. The 1923 Kanto earthquake (M=7.9) and the 1703 Kanto earthquake (M~8.0) are two of the most devastating earthquake those struck Tokyo Metropolitan area, respectively. These earthquakes brought large (~5 m) tsunami to the coast area and uplifted the Miura peninsula by ~1.4 m. The tide gauge station, moreover, records the subsidence during the interseismic period before and after the 1923 earthquake. Present study clarifies the past Kanto earthquake prior to the 1703 earthquake based on the sedimentary analysis in the Koajiro bay of the southern Miura Peninsula. The continuous samples of inner bay fine sediments were taken by the boring survey using 3-m-long geoslicer. Three layers of coarse sediments, T1, T2, and T3 units from top toward bottom, are observed in the bay sediments at almost all the sites. These units are composed of mixture of materials such as shell fragments, rock clasts and gravel, and some of units have eroded the lower fine sediments, indicating the event deposits by the strong traction flow. The grain sizes of the bay sediments are grading upward and abruptly become larger after the deposition of the T1, T2 and T3 units. Very little diatom is observed in these units, but the total number of diatoms increase in the bay sediments. The ratio of the marine planktonic species against the benthic species gradually rises from the lower part to the upper part in the bay sediment. In the tidal flat sediment, the freshwater planktonic species appear in place of the marine planktonic diatom. The changes of grain size and diatom species make a presumption that the sea depth suddenly becomes shallow by the event and deeper during the interseismic period. The T1, T2 and T3 units, thus, are correlated with the tsunami deposits conveyed by the Kanto earthquake. The T1 and T2 units are inferred to be the tsunami

  11. Genome-Wide SNP Discovery, Genotyping and Their Preliminary Applications for Population Genetic Inference in Spotted Sea Bass (Lateolabrax maculatus)

    PubMed Central

    Wang, Juan; Xue, Dong-Xiu; Zhang, Bai-Dong; Li, Yu-Long; Liu, Bing-Jian; Liu, Jin-Xian

    2016-01-01

    Next-generation sequencing and the collection of genome-wide single-nucleotide polymorphisms (SNPs) allow identifying fine-scale population genetic structure and genomic regions under selection. The spotted sea bass (Lateolabrax maculatus) is a non-model species of ecological and commercial importance and widely distributed in northwestern Pacific. A total of 22 648 SNPs was discovered across the genome of L. maculatus by paired-end sequencing of restriction-site associated DNA (RAD-PE) for 30 individuals from two populations. The nucleotide diversity (π) for each population was 0.0028±0.0001 in Dandong and 0.0018±0.0001 in Beihai, respectively. Shallow but significant genetic differentiation was detected between the two populations analyzed by using both the whole data set (FST = 0.0550, P < 0.001) and the putatively neutral SNPs (FST = 0.0347, P < 0.001). However, the two populations were highly differentiated based on the putatively adaptive SNPs (FST = 0.6929, P < 0.001). Moreover, a total of 356 SNPs representing 298 unique loci were detected as outliers putatively under divergent selection by FST-based outlier tests as implemented in BAYESCAN and LOSITAN. Functional annotation of the contigs containing putatively adaptive SNPs yielded hits for 22 of 55 (40%) significant BLASTX matches. Candidate genes for local selection constituted a wide array of functions, including binding, catalytic and metabolic activities, etc. The analyses with the SNPs developed in the present study highlighted the importance of genome-wide genetic variation for inference of population structure and local adaptation in L. maculatus. PMID:27336696

  12. A Compilation of the Historical Earthquakes Database for Marmara Region from 2000 B.C. and 1900 A.D. in frame of Marsite and Mardim Projects

    NASA Astrophysics Data System (ADS)

    Basarir Basturk, Nilay; Meral Ozel, Nurcan

    2016-04-01

    This study aimed at contributing to creation of a scenario database for tsunamigenic earthquakes occurred in Marmara Region through the investigation of the historical earthquakes under the frame of Marsite and also Mardim Projects for the work package 5 (WP5). Furthermore, this work provides an evaluation of earthquake history in Marmara Region which is important for seismic risk assesment in İstanbul and preparing an active fault map of the Sea of Marmara,which is one of the goals of the work package 7 (WP7) of Marmara Supersite Project. For this purpose, we have created a digital database containing 576 earthquakes with some parameters such as location and intensity, also including macroseismic explanations for Turkey between the dates of 2000 B.C. and 1900 A.D. by compiling over 20 available sources such as Ambraseys(2009), Ambraseys and Finkel(1995), Ergin et al. (1967 and 1971), Soysal et al. (1981), Guidoboni et al. (1994), Papazachos et al. (1997), Shebalin & Tatevossian (1997), Ambraseys & Jackson (1998), Kondorskaya & Ulomov (1999), Ambraseys & Jackson (2000), Guidoboni & Comastri(2005), Stucchi et al(2012), Papazachos&P.,(2003). Among these sources, the basic reference that we used for many earthquakes is the Soysal et al. (1981), including earthquake parameters such as macroseismic epicenter and intensity. Another important catalogue for the assessment of historical events is the Ambraseys (2009) which is a comprehensive review and contains macroseismic explanations of the earthquakes in Turkey from 2000 B.C. to 1900 A.D. Evaulation of every possible sources for the old earthquakes have enabled us to cross check differences among them , find dublicate events and debate the earthquakes in terms of their reliability. In the scope of this study, the historical earthquakes were classified to date, location, intensity, macroseismic explanations using available information. In addition, the coordinate and intensity were assigned to 343 and 114 events

  13. Earthquake and Tsunami Disaster Mitigation in The Marmara Region and Disaster Education in Turkey. (SATREPS Project: Science and Technology Research Partnership for Sustainable Development by JICA-JST)

    NASA Astrophysics Data System (ADS)

    Kaneda, Y.; Erdik, M. O.; Takahashi, N.; Meral Ozel, N.; Hori, T.; Hori, M.; Kumamoto, K.; Kalafat, D.; Pinar, A.; Ozel, A. O.; Yalciner, A. C.; Nurlu, M.; Tanircan, G.; Citak, S.; Ariyoshi, K.; Necmioglu, O.

    2014-12-01

    Since 1900, around 90,000 people have lost their lives in 76 earthquakes occurred in Turkey, with a total affected population of ~7 million and direct estimated losses of ~25 billion USD. About half the lives lost were due to two earthquakes associated with the North Anatolian Fault in 1939 and 1999. During this time, seven large westward-migrating earthquakes created a 900-km-long continuous surface rupture along the fault zone from Erzincan to the Marmara Sea, stopping just short of Istanbul. Based on a time-dependent model that includes coseismic and postseismic effects of the 1999 Kocaeli earthquake with moment magnitude (Mw) = 7.4, Parsons concluded that the probability of an earthquake with Mw >7 in the Sea of Marmara near Istanbul is 35% to 70% in the next 30 years. This high probability is shared by Tokyo and San Francisco; however, the earthquake fragility of the pre-2000 building stock in Turkey is much higher than that of California or Japan. (Erdik, 2013). All of the arguments described above provide a sound basis for a Japanese-Turkish partnership enabling each partner to share experiences gained from past destructive earthquakes and prepare for expected large earthquakes. The SATREPS project aims to address this need, also focusing on the tsunami hazard. The project's main objectives are i) to develop disaster mitigation policies and strategies based on multidisciplinary research activities; ii) to provide decision makers with newly found knowledge for its implementation to the current regulations; iii) to organize disaster education programs in order to increase disaster awareness in Turkey; iv) to contribute the evaluation of active fault studies in Japan. To achieve successfully these objectives, 4 research groups have been set specializing on observations, simulations, civil engineering and disaster education and the results will be integrated for disaster mitigation in the Marmara region and disaster education in Turkey.

  14. The multi-parameter borehole system and high resolution seismic studies in the western part of the main Marmara Fault in the frame of MARSITE Project.

    NASA Astrophysics Data System (ADS)

    Ozel, Oguz; Guralp, Cansun; Tunc, Suleyman; Yalcinkaya, Esref

    2016-04-01

    The main objective of this study is to install a multi-parameter borehole system and surface array as close to the main Marmara Fault (MMF) in the western Marmara Sea as possible, and measure continuously the evolution of the state of the fault zone surrounding the MMF and to detect any anomaly or change, which may occur before earthquakes by making use of the data from the arrays already running in the eastern part of the Marmara Sea. The multi-parameter borehole system is composed of very wide dynamic range and stable borehole (VBB) broad band seismic sensor, and incorporate strain meter, tilt meter, and temperature and local hydrostatic pressure measuring devices. The borehole seismic station uses the latest update technologies and design ideas to record "Earth tides" signals to the smallest magnitude -3 events. Additionally, a surface microearthquake observation array, consisting of 8-10 seismometers around the borehole is established to obtain continuous high resolution locations of micro-seismicity and to better understand the existing seismically active structures and their roles in local tectonic settings.Bringing face to face the seismograms of microearthquakes recorded by borehole and surface instruments portrays quite different contents. The shorter recording duration and nearly flat frequency spectrum up to the Nyquist frequencies of borehole records are faced with longer recording duration and rapid decay of spectral amplitudes at higher frequencies of a surface seismogram. The main causative of the observed differences are near surface geology effects that mask most of the source related information the seismograms include, and that give rise to scattering, generating longer duration seismograms. In view of these circumstances, studies on microearthquakes employing surface seismograms may bring on misleading results. Particularly, the works on earthquake physics and nucleation process of earthquakes requires elaborate analysis of tiny events. It is

  15. Modelling of glacial isostatic adjustment in the Barents Sea region: Earth rheology inferred from various ice load scenarios for the last glacial cycle

    NASA Astrophysics Data System (ADS)

    Auriac, Amandine; Whitehouse, Pippa L.; Bentley, Michael J.; Patton, Henry; Hubbard, Alun; Lloyd, Jerry M.

    2015-04-01

    The Barents Sea, bordered by Norway to the south, Svalbard to the north and Novaya Zemlya to the east, was covered by ice during the last glacial cycle. The extent and thickness of the marine-based ice sheet as well as timing of glaciation / deglaciation are, however, difficult to constrain, partly due to the few terrestrial areas available. There are various models for the ice load history in this region, but large discrepancies remain between them depending on the dataset used as constraint (e.g. sea-level data, temperature record or geomorphology data). Our aim here is to compare and find the best ice load scenario for this region over the last glacial cycle and solve for the Earth structure in the area. To achieve this, we model the present-day crustal deformation and sea-level variations during the last deglaciation by solving the sea-level equation. We use a wide range of Earth models, where we vary the lithosphere thickness and the upper and lower mantle viscosities, as well as four ice load scenarios. The first three ice load scenarios come from published studies, and include the ICE-5G model as well as models from M. Siegert and J.-O. Näslund, while the last one is currently being developed at the University of Tromsø, Norway. We compare the modelled sea-level predictions to relative sea-level curves at key locations around the Barents Sea using chi square, which enables us to infer the best Earth structure and ice history. We also compare the predicted surface deformation from our best model with GPS observations from stations located around the Barents Sea. The GPS provides a constraint on the present-day evolution of deformation in the area and is complementary to the relative sea-level data, which constrain the long-term deformation. First results show that the published ice load scenarios are not accurate enough to reproduce the sea level curves around the Barents Sea, regardless of the Earth model tried. However, the last model, currently being

  16. New Directions in Seismic Hazard Assessment Through Focused Earth Observation in the MARmara SuperSITE - Project Achievements

    NASA Astrophysics Data System (ADS)

    Meral OZel, Nurcan; Necmioǧlu, Öcal; Ergintav, Semih; Ozel, Oǧuz; Favali, Paolo; Bigarre, Pascal; Çakır, Ziyadin; Ozeren, Sinan; Geli, Louis; Douglas, John; Aochi, Hideo; Bossu, Remy; Zülfikar, Can; Şeşetyan, Karin; Erdik, Mustafa

    2016-04-01

    The MARsite Project, which started in November 2012,funded by the EC/ FP7-ENV.2012 6.4-2 (Grant 308417) identifies the Marmara region as a 'Supersite' within European initiatives to aggregate on-shore, off-shore and space-based observations, comprehensive geophysical monitoring, improved hazard and risk assessments encompassed in an integrated set of activities. MARsite aimed to harmonize geological, geophysical, geodetic and geochemical observations to provide a better view of the post-seismic deformation of the 1999 Izmit earthquake (in addition to the post-seismic signature of previous earthquakes), loading of submarine and inland active fault segments and transient pre-earthquake signals, related to stress loading with different tectonic properties in and around Marmara Sea. This presentation provides an overview of the achievements of MARSite which aimed to coordinate research groups ranging from seismology to gas geochemistry in a comprehensive monitoring activity developed in the Marmara Region based on collection of multidisciplinary data to be shared, interpreted and merged in consistent theoretical and practical models suitable for the implementation of good practices to move the necessary information to the end users in charge of seismic risk management of the region. In addition, processes involved in earthquake generation and the physics of short-term seismic transients, 4D deformations to understand earthquake cycle processes, fluid activity monitoring and seismicity under the sea floor using existing autonomous instrumentation, early warning and development of real-time shake and loss information, real- and quasi-real-time earthquake and tsunami hazard monitoring and earthquake-induced landslide hazard topics are also covered within MARSite. In particular, achievements and progress in the design and building of a multi-parameter borehole system consisting of very wide dynamic range and stable borehole (VBB) broad band seismic sensor, with

  17. Ecology of the Atlantic black skipjack Euthynnus alletteratus (Osteichthyes: Scombridae) in the western Mediterranean Sea inferred by parasitological analysis.

    PubMed

    Mele, Salvatore; Pennino, M Grazia; Piras, M Cristina; Macías, David; Gómez-Vives, M José; Alemany, Francisco; Montero, Francisco E; Garippa, Giovanni; Merella, Paolo

    2016-09-01

    Between 2008 and 2011, the head of 150 Euthynnus alletteratus (Osteichthyes: Scombridae) caught inshore off the southeastern Iberian coast (western Mediterranean Sea) were examined for parasites. Two monogeneans, four didymozoid trematodes and four copepods were found. Parasite abundance showed a positive relationship with the annual sea surface temperature, except for Pseudocycnus appendiculatus, but negative with the sea depth (Capsala manteri, Neonematobothrium cf. kawakawa and Caligus bonito). Prevalences and mean abundances differed significantly among sampling areas, except for C. manteri, Oesophagocystis sp. 2 and Ceratocolax euthynni, and sampling years (Melanocystis cf. kawakawa, N.cf. kawakawa, P. appendiculatus and Unicolax collateralis). Results indicate that the parasite abundances of E. alletteratus in the western Mediterranean Sea depend mainly on regional environmental variables, which can show interannual variations. The presence of pelagic parasites, i.e. didymozoids and P. appendiculatus, could indicate that E. alletteratus migrates between inshore and offshore pelagic domains. The different parasite faunas reported in E. alletteratus populations from the western Atlantic Ocean and the Mediterranean Sea appear to point out the geographical host isolation. These results suggest that E. alletteratus inhabiting the western Mediterranean Sea performs inshore-offshore small-scale migrations, and not transoceanic migrations between the western Atlantic Ocean and Mediterranean Sea.

  18. Spectral Determination of Source Parameters in The Marmara Region

    NASA Astrophysics Data System (ADS)

    Koseoglu, A.; Meral Ozel, N.; Barıs, S.

    2014-12-01

    Ever since the 1999 Kocaeli Earthquake, in which the Kandilli Observatory and Earthquake Research Institute (KOERI) was not able to correctly reflect the magnitude size in its preliminary report because of the saturation effect, a rapid and accurate determination of the earthquake becomes a very important issue. Therefore, in the framework of this study an automatic determination of the moment magnitude was performed by using the displacement spectra of selected earthquakes in Marmara Region. For this purpose 39 three component broadband stations from KOERI seismic network which recorded 174 earthquakes with magnitudes 2.5≤M≤5.0 in between 2006-2009 were used. Due to the importance of quality factor in determination of the moment magnitude with spectral analysis method, the quality factor was calculated for the whole region in the beginning. Source spectrum which was obtained by converting the velocity records to displacement spectra and moment magnitudes of earthquakes were determined by fitting this spectrum to classical Brune model. For this aim, an automatic procedure was utilized which based on minimizing the differences between observed and synthetic source spectra identified by the S-waves. Besides of moment magnitude and location parameters, some source parameters such as seismic moment, spectral level, corner frequency and stress drop were also calculated. Application of the method proves that determine the seismic moment from the source spectra is applicable not only for earthquakes with small magnitude but also moderate earthquakes as well.

  19. Infectious complications after mass disasters: the Marmara earthquake experience.

    PubMed

    Keven, Kenan; Ates, Kenan; Sever, Mehmet Sukru; Yenicesu, Mujdat; Canbakan, Basol; Arinsoy, Turgay; Ozdemir, Nurhan; Duranay, Murat; Altun, Bulent; Erek, Ekrem

    2003-01-01

    The Marmara earthquake occurred on 17 August 1999. There were 639 renal victims, of whom 477 needed some form of renal replacement therapy. Although several medical complications have been reported in the literature, there has been no detailed description of infectious complications in patients with crush syndrome after earthquakes. Data from 35 hospitals considering clinical and laboratory findings, as well as infectious complications and the results of microbiological examinations, were analysed. 223 out of 639 (34.9%) patients had infectious complications, which comprised the most frequent medical problem in the renal victims. The patients who suffered from infections had a higher mortality rate than those who did not (p = 0.03). Sepsis and wound infection were the main presentation of the infectious complications. 121 (18.9%) patients suffered from sepsis; the mortality rate was higher in these patients (27.3%) than in victims who did not suffer from sepsis (12.4%, p < 0.0001). In a multivariate model, sepsis was associated with increased mortality (p = 0.0002, odds ratio 2.45, 95% confidence interval 1.52-3.96). 53 (8.2%) and 41 (6.4%) patients had wound and pulmonary infections, respectively. Most of the infections were nosocomial in origin and caused by Gram-negative aerobic bacteria and Staphylococcus spp. Infectious complications are common in renal victims of catastrophic earthquakes and are associated with increased mortality when complicated by sepsis.

  20. Free and Forced Rossby Waves in the Western South China Sea Inferred from Jason-1 Satellite Altimetry Data.

    PubMed

    Wu, Xiangyu; Xie, Qiang; He, Zhigang; Wang, Dongxiao

    2008-06-01

    Data from a subsurface mooring deployed in the western South China Sea shows clear intra-seasonal oscillations (ISO) at the period of 40~70 days. Analysis of remotelysensed sea surface height (SSH) anomalies in the same area indicates that these ISO signals propagate both eastward and westward. Time-longitude diagrams of ISO signals in SSH anomalies and wind-stress curl indicate that the eastward propagating SSH anomalies is forced by wind-stress curl. This is also confirmed by lag correlation between SSH anomalies and the wind-stress-curl index (wind stress curl averaged over 109.5ºE -115ºE and 12ºN -13.5ºN). Lag correlation of SSH anomaly suggests that the westward propagating signals are free Rossby waves.

  1. Late Holocene sea level changes and tectonic movements inferred from fossil diatom assemblages in Tainohama, Tokushima prefecture, Japan

    NASA Astrophysics Data System (ADS)

    Chiba, T.; Fujino, S.; Kobori, E.

    2014-12-01

    The average recurrence interval of the interplate earthquakes along the Nankai Trough is estimated from historical literature and archaeological data. However, the details of tectonic movements by past Nankai earthquakes are mostly left unclear from historical literature, therefore, we need to obtain the geological evidence of the tectonic movements. Yuki city, Tokushima prefecture, located in north part of the Nankai Trough, has been subsided and many tsunamis attacked along the coast of the Shikoku islands accompanied by the previous Nankai earthquakes. Therefore, some historical documents and memorial monuments written about the past Nankai earthquakes and tsunamis remain in the city. The study purposed to reveal tectonic movements of the earthquakes from Nankai Trough during the late Holocene at Tainohama in Minami city which is adjacent to the southwest of Yuki city by fossil diatom analysis. We obtained a 700cm long core at a marsh behind a barrier spit probably be not affected directly from sea waves in Tainohama. The core includes more than 13 sand layers in organic-rich muddy or peaty sedimentary succession up to 500cm depth in the core. And the diatom assemblages included in the peat and peaty mud deposits were dominated by fresh and brackish water species, especially Pseudostaurosira brevistriata, P. subsalina and Tabellaria fenestrate. In contrast to the above mentioned sand layers, brackish and marine species, such as Diploneis smithii increased. The diatom assemblages from the organic rich muddy sediments and radiocarbon ages indicate that freshwater marsh or saltmarsh formed in this region during the late Holocene. On the other hand, the sandy layers include the diatoms living in environments where salinities are higher than freshwater or salt marsh, so the assemblages suggest that the sand layers were transported from seaside by past tsunamis. In addition, changes of diatom assemblages in the peaty or peaty mud sediments show increase or decrease of

  2. Israel’s Blockade of Gaza, the Mavi Marmara Incident, and Its Aftermath

    DTIC Science & Technology

    2010-06-23

    Israeli navy zodiac boats intercepted them and naval commandos took over five ships, reportedly without incident. However, the Marmara resisted and...countries signed a free trade agreement in 1996. Observers do not believe that any new deals should be expected. Aside from criticizing Israel’s

  3. Israel’s Blockade of Gaza, the Mavi Marmara Incident, and Its Aftermath

    DTIC Science & Technology

    2010-06-16

    navy zodiac boats intercepted them and naval commandos took over five ships, reportedly without incident. However, the Marmara resisted and...increase before the incident. The two countries signed a free trade agreement in 1996. Observers do not believe that any new deals can be expected

  4. Using an independent geochronology based on palaeomagnetic secular variation (PSV) and atmospheric Pb deposition to date Baltic Sea sediments and infer 14C reservoir age

    NASA Astrophysics Data System (ADS)

    Lougheed, Bryan C.; Snowball, Ian; Moros, Matthias; Kabel, Karoline; Muscheler, Raimund; Virtasalo, Joonas J.; Wacker, Lukas

    2012-05-01

    these sediments. An inferred marine reservoir age offset (ΔR) is calculated by comparing the foraminifera 14C determinations to a PSV & Pb age model. This ΔR is found to trend towards younger values upwards in the core, possibly due to a gradual change in hydrographic conditions brought about by a reduction in marine water exchange from the open sea due to continued isostatic rebound.

  5. Inference of potential genetic risks associated with large-scale releases of red sea bream in Kanagawa prefecture, Japan based on nuclear and mitochondrial DNA analysis.

    PubMed

    Blanco Gonzalez, Enrique; Aritaki, Masato; Sakurai, Shigeru; Taniguchi, Nobuhiko

    2013-04-01

    Since 1978, millions of hatchery-reared red sea bream (Pagrus major) juveniles have been released in Sagami Bay and Tokyo Bay in Kanagawa Prefecture, Japan. The stock enhancement program has contributed to total catch; however, no information regarding the genetic interactions with wild counterparts is available. Here, we combined 15 microsatellite loci and mitochondrial D-loop sequencing to characterize the genetic resources of red sea bream in Sagami Bay and Tokyo Bay and to elucidate the potential harmful genetic effects associated with fish releases. Both types of markers evidenced higher levels of genetic diversity in wild samples (SB and TB) compared with offspring before stocking (H07 and H08) as well as a hatchery-released sample recaptured in Sagami Bay (HR). Microsatellite F (ST) estimates and Bayesian clustering analysis found significant genetic differences among samples (F (ST) = 0.013-0.054), except for the two wild samples (F (ST) = 0.002) and HR vs. H07 (F (ST) = 0.007). On the other hand, mitochondrial-based Ф (ST) suggested haplotypic similarity between SB, H07, and HR. The low effective number of females contributing to the offspring over multiple generations may be responsible for the lack of haplotypic differentiation. Moreover, the putative hatchery origin to three fish (8 %) without deformity in the inter-nostril epidermis was inferred for the first time. Our results showed the usefulness of combining nuclear and mitochondrial markers to elucidate genetic interactions between hatchery-released and wild red sea bream and warned about potential harmful genetic effects should interbreeding takes place.

  6. Genetic diversity in two Japanese flounder populations from China seas inferred using microsatellite markers and COI sequences

    NASA Astrophysics Data System (ADS)

    Xu, Dongdong; Li, Sanlei; Lou, Bao; Zhang, Yurong; Zhan, Wei; Shi, Huilai

    2012-07-01

    Japanese flounder is one of the most important commercial species in China; however, information on the genetic background of natural populations in China seas is scarce. The lack of genetic data has hampered fishery management and aquaculture development programs for this species. In the present study, we have analyzed the genetic diversity in natural populations of Japanese flounder sampled from the Yellow Sea (Qingdao population, QD) and East China Sea (Zhoushan population, ZS) using 10 polymorphic microsatellite loci and cytochrome c oxidase subunit I (COI) sequencing data. A total of 68 different alleles were observed over 10 microsatellite loci. The total number of alleles per locus ranged from 2 to 9, and the number of genotypes per locus ranged from 3 to 45. The observed heterozygosity and expected heterozygosity in QD were 0.733 and 0.779, respectively, and in ZS the heterozygosity values were 0.708 and 0.783, respectively. Significant departures from Hardy-Weinberg equilibrium were observed in 7 of the 10 microsatellite loci in each of the two populations. The COI sequencing analysis revealed 25 polymorphic sites and 15 haplotypes in the two populations. The haplotype diversity and nucleotide diversity in the QD population were 0.746±0.072 8 and 0.003 34±0.001 03 respectively, and in ZS population the genetic diversity values were 0.712±0.047 0 and 0.003 18±0.000 49, respectively. The microsatellite data ( F st =0.048 7, P <0.001) and mitochondrial DNA data ( F st =0.128, P <0.001) both revealed significant genetic differentiation between the two populations. The information on the genetic variation and differentiation in Japanese flounder obtained in this study could be used to set up suitable guidelines for the management and conservation of this species, as well as for managing artificial selection programs. In future studies, more geographically diverse stocks should be used to obtain a deeper understanding of the population structure of Japanese

  7. Water-level oscillations in the Adriatic Sea as coherent self-oscillations inferred by independent component analysis

    NASA Astrophysics Data System (ADS)

    Capuano, P.; De Lauro, E.; De Martino, S.; Falanga, M.

    2011-12-01

    We analyze tide gauge records at four stations of the ISPRA network located in the Adriatic Sea basin (Eastern Italy), namely, going from North to South: Trieste, Ancona, Ortona and Otranto. We use linear and nonlinear methods in the frequency and time domains, including spectral and Independent Component Analysis (ICA), inter-times occurrence, and phase space embedding dimension evaluation. We show that four tidal constituents can be extracted by ICA and interpreted as coherent self-sustained oscillations. Finally, we show that these constituents can be reproduced by adopting a simple nonlinear oscillatory model that generalizes classical Andronov oscillator with the inclusion of a time dependent pumping.

  8. Inferred calcification rate of a Mediterranean azooxanthellate coral is uncoupled with sea surface temperature along an 8° latitudinal gradient

    PubMed Central

    2012-01-01

    Introduction Correlations between sea surface temperature (SST) and growth parameters of the solitary azooxanthellate Dendrophylliid Leptopsammia pruvoti were assessed along an 8° latitudinal gradient on western Italian coasts (Mediterranean Sea), to check for possible negative effects of increasing temperature as the ones reported for a closely related, sympatric but zooxanthellate species. Results Calcification rate was correlated with skeletal density but not with linear extension rate, indicating that calcium carbonate deposition was preferentially allocated to keep a constant skeletal density. Unlike most studies on both temperate and tropical zooxanthellate corals, where calcification rate is strongly related to environmental parameters such as SST, in the present study calcification rate was not correlated with SST. Conclusions The lower sensitivity of L. pruvoti to SST with respect to other sympatric zooxanthellate corals, such as Balanophyllia europaea, may rely on the absence of a temperature induced inhibition of photosynthesis, and thus the absence of an inhibition of the calcification process. This study is the first field investigation of the relationship between SST and the three growth parameters of an azooxanthellate coral. Increasing research effort on determining the effects of temperature on biological traits of the poorly studied azooxanthellate scleractinians may help to predict the possible species assemblage shifts that are likely to occur in the immediate future as a consequence of global climatic change. PMID:23163981

  9. Evolution of the oceanic lithosphere inferred from Po/So waves traveling in the Philippine Sea Plate

    NASA Astrophysics Data System (ADS)

    Shito, Azusa; Suetsugu, Daisuke; Furumura, Takashi

    2015-07-01

    Po/So waves are characterized by their high-frequency content and long-duration travel over great distances (up to 3000km) through the oceanic lithosphere. Po/So waves are developed by the multiple forward scattering of P and S waves due to small-scale stochastic random heterogeneities. To study the nature of these heterogeneities, Po/So waves are analyzed in the Philippine Sea Plate, which consists of three regions with different lithospheric ages. In the Philippine Sea Plate, Po/So waves propagate in the youngest region (15 Ma) and propagate more effectively in older regions. We investigate the mechanism of this propagation efficiency using numerical finite difference method simulations of 2-D seismic wave propagation. The results of this study demonstrate that the increase in propagation efficiency of Po/So waves depends on the age of the oceanic lithosphere, and this relationship can be qualitatively explained by thickening of the oceanic lithosphere including small-scale heterogeneities and a reduction in the intrinsic attenuation. These small-scale heterogeneities may form continuously in oceanic lithosphere from the time of its formation at a spreading ridge, via the solidification of melts distributed in the asthenosphere.

  10. Integrated Multidisciplinary Fault Observation System in the western part of the main Marmara Fault in the frame of an EU-FP7 project, titled as MARSITE

    NASA Astrophysics Data System (ADS)

    Ozel, Oguz; Guralp, Cansun; Tunc, Suleyman; Yalcinkaya, Esref; Meral Ozel, Nurcan

    2015-04-01

    The main objective of this study is to install a multi-parameter borehole system and surface array consisting of eight broadband sensors as close to the main Marmara Fault (MMF) in the western Marmara Sea as possible, and measure continuously the evolution of the state of the fault zone surrounding the MMF and to detect any anomaly or change which may occur before earthquakes by making use of the data from these arrays. The multi-parameter borehole system is composed of very wide dynamic range and stable borehole (VBB) broad band seismic sensor, and incorporate 3-D strain meter, tilt meter, and temperature and local hydrostatic pressure measuring devices. All these sensors are installed in 146m-deep borehole. All the sensor outputs are digitized; total of 11*24 bit-channels and 6*20 bit-channels. Real-time data transmission to the main server of the Marsite Project at Kandilli Observatory in Istanbul is accomplished. The multi-parameter borehole seismic station uses the latest update technologies and design ideas to record "Earth tides" signals to the smallest magnitude -3 events, as the innovative part of the Marsite Project. Bringing face to face the seismograms of microearthquakes recorded by borehole and surface instruments portrays quite different contents. The shorter recording duration and nearly flat frequency spectrum up to the Nyquist frequencies of borehole records are faced with longer recording duration and rapid decay of spectral amplitudes at higher frequencies of a surface seismogram. The main causative of the observed differences are near surface geology effects that mask most of the source related information the seismograms include, and that give rise to scattering, generating longer duration seismograms. In view of these circumstances, studies on microearthquakes employing surface seismograms may bring on misleading results. Particularly, the works on earthquake physics and nucleation process of earthquakes requires elaborate analysis of tiny

  11. Investigation of Wind Speed Persistence Over Marmara Region

    NASA Astrophysics Data System (ADS)

    Özgür, Evren; Koçak, Kasım

    2016-04-01

    Persistence is a measure of continuity of a variable over a period of time at any location. This definition implies that wind speed persistence means a positive serial correlation in a time series. In literature, there are numerous methods for measuring wind speed persistence. In this study, wind speed persistence were obtained for 19 stations located in Marmara Region by using two different methods. Daily wind speed data, taken from Turkish State Meteorological Service, were used in the study. The observation period was taken to be 1965-2014 for all stations. The methods used in the study are directional statistical method and wind speed duration curves approach. In directional statistical method, individual dates of winds are defined as directional variables; then, directional mean and variance are calculated. Wind dates are being converted to angular values and these days are being considered as a unit vector which has direction θ. In polar coordinate, the measures of directional mean and variance have been expressed as a vector with direction θmean and magnitude r. The r value can be considered as a measure of persistence. The wind speed duration curve is simply the cumulative distribution function of the wind speed in a certain period of time. In other words, it is the graphical representation of wind speed and percentage of exceedence time for a predefined threshold wind speed value in the same graphic. As a threshold wind speed, lower quartile (q0.25) value of ranked wind speed data were selected. In application, total time period was divided into five subperiods and changes of persistence in wind speeds as far as subperiods were presented. Persistence can be used in different kinds of study areas such as control of forest fires, dispersion of air pollutants, calculation of wind energy potential, ventilation of a city, etc. The results of this analysis showed that the proposed methods can be used as an alternative approach to determine whether a given time

  12. Assessment of ionospheric threat modeling techniques over Marmara Region

    NASA Astrophysics Data System (ADS)

    Onur Karslioglu, Mahmut; Yeganehsahab, Amir; Durmaz, Murat

    2016-04-01

    It is generally known that extreme ionospheric density associated with severe magnetic storm degrades the Global Navigation satellite Systems (GNSS) measurements also at mid - to high latitudes. Strong solar activity can cause large local spatial and temporal gradients in the delays induced on the GNSS signals by the ionosphere. The local nature of gradients can result in significant decorrelation between Ground Based Augmentation System (GBAS) Ground Stations and the GNSS receiver on board the aircraft. For the mitigation of this effect either a special functional architecture is established to monitor the ionosphere on the basis of so called Extended GBAS or ionospheric threat models can be constructed for a certain region. In this work two different techniques have been evaluated for the estimation of ionospheric threat model parameters consisting of width, slope and velocity of the ionospheric wave front by using real ground-based observations from both GPS and GLONASS in the Marmara Region. The data collected between 2012 and 2015 also containing high ionospheric activities are pre-processed to extract ionospheric gradients. Ionospheric delays at each ionospheric piercing point are determined by applying a local ionospheric Total Electron Content (TEC) modeling and filtering techniques on the basis of raw carrier-phase observations. The ionospheric fronts are searched by looking at high ionospheric gradients which result from ionospheric delay differences between ionospheric piercing points. The first technique of the threat model evaluation is based on the propagation of an ideal plane wave as a wave front, velocity of which is estimated on the basis of a Gauss Markov Model using an ordinary least square estimation procedure. The remaining parameters namely slope and width are calculated afterwards using rate of change gradients and the duration of the wave front in context with the estimated front velocity. In the second technique both the magnitude of the

  13. Genetic structure of Octopus vulgaris (Cephalopoda, Octopodidae) in the central Mediterranean Sea inferred from the mitochondrial COIII gene.

    PubMed

    Fadhlaoui-Zid, Karima; Knittweis, Leyla; Aurelle, Didier; Nafkha, Chaala; Ezzeddine, Soufia; Fiorentino, Fabio; Ghmati, Hisham; Ceriola, Luca; Jarboui, Othman; Maltagliati, Ferruccio

    2012-01-01

    The polymorphism of the mitochondrial gene cytochrome oxidase III was studied in the Mediterranean octopus, Octopus vulgaris Cuvier, 1797. A total of 202 specimens from seven sampling sites were analysed with the aim of elucidating patterns of genetic structure in the central Mediterranean Sea and to give an insight into the phylogeny of the Octopus genus. Phylogenetic analyses showed that individuals from the central Mediterranean belong to the O. vulgaris species whose limits should nevertheless be clarified. Concerning genetic structure, two high-frequency haplotypes were present in all locations. The overall genetic divergence (Φ(ST)=0.05, P<0.05) indicated a significant genetic structuring in the study area and an AMOVA highlighted a significant break between western and eastern Mediterranean basins (Φ(CT)=0.094, P<0.05). Possible explanations for the observed patterns of genetic structuring are discussed with reference to their relevance for fisheries management.

  14. The role of mesoscale processes controlling biological variability in the Black Sea coastal waters: inferences from SeaWIFS-derived surface chlorophyll field

    NASA Astrophysics Data System (ADS)

    Oguz, T.; Deshpande, A. G.; Malanotte-Rizzoli, P.

    2002-06-01

    Several different time series of chlorophyll images from the 1997-2000 Seaviewing Wide Field-of-view Sensor data set have been analysed to gain a perspective on the dynamical and biological variability in the Black Sea, particularly on its northwestern shelf region and along the Anatolian coastal zone. The images are interpreted in terms of documenting the close link between biological production and physical dynamics of the boundary system, and of emphasizing the role of eddy processes on controlling mesoscale chlorophyll distributions. It is shown that western coastal waters of the Black Sea are characterized by permanently high chlorophyll concentrations of more than 4.0 mg m -3, often subject to considerable dynamical transformations, and modulated by mesoscale structures including southward elongated filament-like features extending up to 100 km offshore with a lifetime of up to a month. Filaments, meanders, offshore jets and other forms of mesoscale and sub-mesoscale structures appear as a common signature of the system along the Anatolian coast. They play an important role in the cross-stream transport of biota and chemical constituents, and thus supporting productivity within the interior parts of the basin. The images reveal phytoplankton blooms lasting several months in all three autumn seasons. During autumn 1999 to winter 2000, the phytoplankton biomass declines in December, and then increases to form another bloom in February-March 2000, albeit somewhat weaker. For the previous 2 years (1997, 1998), the autumn bloom is extended towards the first half of the winter but the late winter-early spring bloom is absent.

  15. Patterns and inferred processes associated with sea turtle strandings in Paraíba State, Northeast Brazil.

    PubMed

    Poli, C; Lopez, L C S; Mesquita, D O; Saska, C; Mascarenhas, R

    2014-05-01

    This study analysed sea turtle strandings on the coast of Paraíba State, Northeastern Brazil, from August 2009 to July 2010. A total of 124 strandings were recorded in this period: green turtle Chelonia mydas (n = 106), hawksbill Eretmochelys imbricata (n = 15), olive ridley Lepidochelys olivacea (n = 2) and loggerhead Caretta caretta (n = 1). Of all turtles for which the Curved Carapace Length (CCL) was measured (n = 122), only 12 individuals (9.7%) were adults. Twenty individuals had synthetic anthropogenic debris in the gastrointestinal tract. Other traces of human interactions were observed in 43 individuals, such as injuries caused by entanglement in fishing lines or nets, collisions with vessels, direct contact with oil spills and lesions caused by sharp or spiked objects. Moreover, in 28.5% of the stranded turtles, the presence of external tumors was noticed, suggestive of fibropapillomatosis and in 9.7%, shark bite marks were observed. Of the 107 individuals that were sexed, 76 were females and 31 were males. Most turtles (72.6%) became stranded during the spring/summer (between October and March). We found evidence of human interactions (injuries) in half of the strandings, but in most cases it was not possible to determine if such interactions were the cause of death. A logistic regression found a significant relationship between CCL, ingestion of debris and lesions caused by sharks or spiked objects. Systematic data collection from stranded sea turtles can provide useful biological information, such as seasonal and spatial patterns in their occurrence and mortality, age structure, sex ratio and diet, as well as possible mortality causes.

  16. Development of the Sea Star Echinaster (Othilia) brasiliensis, with Inference on the Evolution of Development and Skeletal Plates in Asteroidea.

    PubMed

    Lopes, Elinia Medeiros; Ventura, Carlos Renato Rezende

    2016-02-01

    We describe the development and juvenile morphology of the sea star Echinaster (Othilia) brasiliensis in order to explore evolutionary developmental modes and skeletal homologies. This species produces large, buoyant eggs (0.6 ± 0.03 mm diameter), and has a typical lecithotrophic brachiolaria larva. The planktonic brachiolaria larva is formed 2-4 days after fertilization, when cilia cover the surface. Early juveniles are completely formed by 18 days of age. Initial growth is supported by maternal nutrients while the stomach continues to develop until 60 days after fertilization, when juveniles reach about 0.5 mm of radius length. The madreporite was observed 88 days after fertilization. In the youngest juvenile skeleton of E. (O.) brasiliensis, the madreporite and odontophore are homologous to those of other recent, non-paxillosid asteroids, and follow the Late Madreporic Mode. The emergence of plates related to the ambulacral system follows the Ocular Plate Rule. The development and juvenile skeletal morphology of this species are similar to those of the few other studied species in the genus Echinaster. This study corroborates the notion that the mode of development--including a short-lived lecithotrophic brachiolaria larva--in all Echinaster species shares a similar pattern that may be conserved throughout the evolutionary history of the group.

  17. Geophysical evidence and inferred triggering factors of submarine landslides on the western continental margin of the Ulleung Basin, East Sea

    NASA Astrophysics Data System (ADS)

    Cukur, Deniz; Kim, Seong-Pil; Kong, Gee-Soo; Bahk, Jang-Jun; Horozal, Senay; Um, In-Kwon; Lee, Gwang-Soo; Chang, Tae-Soo; Ha, Hun-Jun; Völker, David; Kim, Jung-Ki

    2016-12-01

    Submarine landslides form very complex depositional and erosional features on the seafloor, and their dynamics and triggering processes are yet to be understood completely. Numerous studies are being undertaken both because of the scientific significance but also for their potential harm to seafloor infrastructure and coastal areas. This study investigates the styles and causes of landsliding along the western margin of the Ulleung Basin in the East Sea, based on multiple sparker, subbottom profiler, multibeam echosounder and sediment core datasets collected in 2015. The bathymetric analyses indicate that the southern slope of the Ulleung Basin has experienced at least seven submarine failures. These failures left clear arcuate-shaped scarps that initiated at water depths of 600 m. The observed headwall scarps have heights that exceed 60 m and appear to be the result of retrogressive-type failures. Seismic reflection data clearly image the basal sliding surface that is characterized by a prominent high-amplitude reflector. Chaotic-to-transparent seismic facies occur immediately downslope of the headwall scarps; these represent 20 m thick landslide deposits. Gravity cores taken from areas adjacent to the scars suggest that these slides are older than ca. 97 ka. Interpretation of the present data shows that faults appear to cut recent sediments upslope of scarps, and that the slope may still be in an active phase of failure. Seismic data also image various overpressurized gases and/or gas fluids, as evidenced by the occurrence of pockmarks and seismic chimneys in upslope or adjacent areas of the scarps. Hence, earthquakes associated with tectonic activity and development of fluid overpressure may have acted as the main conditioning factor for destabilizing the slope sediments. Geotechnical stability analyses indicate that the sampled slope sediments are exceptionally stable under present-day conditions, even under seismic loading. This finding points to additional

  18. Atlantic sea surface height and velocity spectra inferred from satellite altimetry and a hierarchy of numerical simulations

    NASA Astrophysics Data System (ADS)

    Biri, Stavroula; Serra, Nuno; Scharffenberg, Martin G.; Stammer, Detlef

    2016-06-01

    Frequency and wavenumber spectra of sea surface height (SSH) and surface geostrophic velocity are presented, as they result for the Atlantic Ocean from a 23 year long altimeter data set and from a hierarchy of ocean model simulations with spatial resolutions of 16, 8, and 4 km. SSH frequency spectra follow a spectral decay of roughly f-1 on long periods; toward higher frequencies a spectral decay close to f-2 is found. For geostrophic velocity spectra, a somewhat similar picture emerges, albeit with flatter spectral relations. In terms of geostrophic velocity wavenumber spectra, we find a general relation close to k-3 in the high-resolution model results. Outside low-energy regions all model spectra come close to observed spectra at low frequencies and wavenumbers in terms of shape and amplitude. However, the highest model resolution appears essential for reproducing the observed spectra at high frequencies and wavenumbers. This holds especially for velocity spectra in mid and high latitudes, suggesting that eddy resolving ocean models need to be run at a resolution of 1/24° or better if one were to fully resolve the observed mesoscale eddy field. Causes for remaining discrepancies between observed and simulated results can be manifold. At least partially, they can be rationalized by taking into account an aliasing effect of unresolved temporal variability in the altimetric observations occurring on periods smaller than the 20 days Nyquist period of the altimetric data, thereby leading to an overestimate of variability in the altimetric estimates, roughly on periods below 100 days.

  19. Geographic genetic structure in two laticaudine sea kraits, Laticauda laticaudata and Laticauda semifasciata (Serpentes: Elapidae), in the Ryukyu-Taiwan region as inferred from mitochondrial cytochrome b sequences.

    PubMed

    Tandavanitj, Nontivich; Ota, Hidetoshi; Cheng, Yuan-Cheng; Toda, Mamoru

    2013-08-01

    The Ryukyu-Taiwan region is an island arch with intervening waters of varying distances and depths. This study examines the geographic genetic structure of two sympatric sea kraits, Laticauda laticaudata and L. semifasciata, in the region, to infer factors affecting the extent of dispersal and other biogeographical traits of these amphibious reptiles. Sequence analyses of the mitochondrial cytochrome b gene revealed four and 16 haplotypes for L. laticaudata (136 individuals) and L. semifasciata (177 individuals), respectively. For both species, population pairwise F ST analyses revealed significant genetic differentiations among islands and island groups, which are separated by deep straits, suggesting that deep waters serve as obstacles for dispersal in both species. Significant genetic differentiation was detected even among islands of the same basin in L. laticaudata, but not in L. semifasciata, and the isolation by distance analyses revealed no significant correlation between geographic and genetic distances in the former species. These results further suggest that L. laticaudata has stronger site fidelity or degree of philopatry than L. semifasciata. Based on the geographic genetic patterns, the historical biogeography of the two species in the Ryukyu-Taiwan region is also discussed.

  20. Performed Surgical Interventions After the 1999 Marmara Earthquake in Turkey, and Their Importance Regarding Nursing Practices.

    PubMed

    Gul, Asiye; Andsoy, Isil Isik

    2015-01-01

    Effectively dealing with earthquakes is especially important for the people who live in areas prone to earthquakes such as the country of Turkey. Trauma related to earthquakes has specific relevance to nursing practice. The purpose of this review was to describe the types of surgical interventions after the Marmara earthquake and to evaluate the implications for nursing care. English and Turkish articles about the Marmara earthquake were reviewed between May and July 2013. A total of 7 studies were evaluated. The number of patients admitted to the units, types of injuries, and surgical treatments were recorded, with a total of 2378 patients with earthquake-related injuries. The most commonly traumatized parts of the body were the extremities. Fasciotomy operations were performed on 286 patients and 75 patients underwent extremity amputations. Predetermining surgical problems and interventions may be useful in planning for possible future problems in the case of a disaster.

  1. Prevalence of staphylococcal enterotoxins, toxin genes and genetic-relatedness of foodborne Staphylococcus aureus strains isolated in the Marmara Region of Turkey.

    PubMed

    Aydin, Ali; Sudagidan, Mert; Muratoglu, Karlo

    2011-08-02

    Staphylococcus aureus is a major foodborne pathogen and it has the ability to produce a number of extracellular toxins. We analyzed 1070 food samples obtained from retail markets and dairy farms in the Marmara Region of Turkey for the presence of S. aureus. Out of 147 isolates, 92 (62.6%) were enterotoxigenic. PCR was used to investigate the presence of staphylococcal enterotoxin genes (sea, seb, sec, sed, see, seg, seh, sei, sej, sek, sel, sem, sen, seo, sep, seq and seu), exfoliative toxin genes (eta and etb) and the toxic-shock syndrome toxin gene (tst). The PCR results showed that 53.3% of the isolates contained staphylococcal enterotoxin-like (SEl) toxin genes (seg, seh, sei, sej, sek, sel, sem, sen, seo, sep, seq and seu) which were more frequent than classical enterotoxin genes (sea to see). Furthermore, seo, sei, sem, seg, seu and sec were found in 37.0, 32.7, 30.4, 29.3, 29.3 and 27.2% of the isolates, respectively. The tst gene was detected and confirmed by DNA sequencing in 9 isolates. The presence of eta and etb were not found in the isolates. Enterotoxigenic capabilities of isolates with SEA-SEE were investigated by ELISA. Enterotoxigenic S. aureus isolates produced one to three enterotoxins, with the most frequently produced types being enterotoxin A and C. There was a correlation of 72.1% between production of a specific toxin and the presence of the respective genes. PFGE analysis was used to identify genetic-relatedness of enterotoxigenic S. aureus isolates and the results revealed that 13 groups of isolates from different or the same origin that contained the same genes showed 100% homology with indistinguishable band patterns. The other enterotoxigenic isolates showed related band patterns with 72-86% homology in sea-, 61-90% homology in sec-, 80-96% homology in seh-, and 69-96% homology in sep-positive isolates. To our knowledge, this is the first study to examine enterotoxins and related gene contents of S. aureus food isolates in the Marmara

  2. Ecological Inference

    NASA Astrophysics Data System (ADS)

    King, Gary; Rosen, Ori; Tanner, Martin A.

    2004-09-01

    This collection of essays brings together a diverse group of scholars to survey the latest strategies for solving ecological inference problems in various fields. The last half-decade has witnessed an explosion of research in ecological inference--the process of trying to infer individual behavior from aggregate data. Although uncertainties and information lost in aggregation make ecological inference one of the most problematic types of research to rely on, these inferences are required in many academic fields, as well as by legislatures and the Courts in redistricting, by business in marketing research, and by governments in policy analysis.

  3. Total meltwater volume since the Last Glacial Maximum and viscosity structure of Earth's mantle inferred from relative sea level changes at Barbados and Bonaparte Gulf and GIA-induced J˙2

    NASA Astrophysics Data System (ADS)

    Nakada, Masao; Okuno, Jun'ichi; Yokoyama, Yusuke

    2016-02-01

    Inference of globally averaged eustatic sea level (ESL) rise since the Last Glacial Maximum (LGM) highly depends on the interpretation of relative sea level (RSL) observations at Barbados and Bonaparte Gulf, Australia, which are sensitive to the viscosity structure of Earth's mantle. Here we examine the RSL changes at the LGM for Barbados and Bonaparte Gulf ({{RSL}}_{{L}}^{{{Bar}}} and {{RSL}}_{{L}}^{{{Bon}}}), differential RSL for both sites (Δ {{RSL}}_{{L}}^{{{Bar}},{{Bon}}}) and rate of change of degree-two harmonics of Earth's geopotential due to glacial isostatic adjustment (GIA) process (GIA-induced J˙2) to infer the ESL component and viscosity structure of Earth's mantle. Differential RSL, Δ {{RSL}}_{{L}}^{{{Bar}},{{Bon}}} and GIA-induced J˙2 are dominantly sensitive to the lower-mantle viscosity, and nearly insensitive to the upper-mantle rheological structure and GIA ice models with an ESL component of about (120-130) m. The comparison between the predicted and observationally derived Δ {{RSL}}_{{L}}^{{{Bar}},{{Bon}}} indicates the lower-mantle viscosity higher than ˜2 × 1022 Pa s, and the observationally derived GIA-induced J˙2 of -(6.0-6.5) × 10-11 yr-1 indicates two permissible solutions for the lower mantle, ˜1022 and (5-10) × 1022 Pa s. That is, the effective lower-mantle viscosity inferred from these two observational constraints is (5-10) × 1022 Pa s. The LGM RSL changes at both sites, {{RSL}}_{{L}}^{{{Bar}}} and {{RSL}}_{{L}}^{{{Bon}}}, are also sensitive to the ESL component and upper-mantle viscosity as well as the lower-mantle viscosity. The permissible upper-mantle viscosity increases with decreasing ESL component due to the sensitivity of the LGM sea level at Bonaparte Gulf ({{RSL}}_{{L}}^{{{Bon}}}) to the upper-mantle viscosity, and inferred upper-mantle viscosity for adopted lithospheric thicknesses of 65 and 100 km is (1-3) × 1020 Pa s for ESL˜130 m and (4-10) × 1020 Pa s for ESL˜125 m. The former solution of (1-3) × 1020

  4. Earthquake induced landslide hazard: a multidisciplinary field observatory in the Marmara SUPERSITE

    NASA Astrophysics Data System (ADS)

    Bigarré, Pascal

    2014-05-01

    Earthquake-triggered landslides have an increasing disastrous impact in seismic regions due to the fast growing urbanization and infrastructures. Just considering disasters from the last fifteen years, among which the 1999 Chi-Chi earthquake, the 2008 Wenchuan earthquake, and the 2011 Tohoku earthquake, these events generated tens of thousands of coseismic landslides. Those resulted in amazing death toll and considerable damages, affecting the regional landscape including its hydrological main features. Despite a strong impetus in research during past decades, knowledge on those geohazards is still fragmentary, while databases of high quality observational data are lacking. These phenomena call for further collaborative researches aiming eventually to enhance preparedness and crisis management. As one of the three SUPERSITE concept FP7 projects dealing with long term high level monitoring of major natural hazards at the European level, the MARSITE project gathers research groups in a comprehensive monitoring activity developed in the Sea of Marmara Region, one of the most densely populated parts of Europe and rated at high seismic risk level since the 1999 Izmit and Duzce devastating earthquakes. Besides the seismic threat, landslides in Turkey and in this region constitute an important source of loss. The 1999 Earthquake caused extensive landslides while tsunami effects were observed during the post-event surveys in several places along the coasts of the Izmit bay. The 6th Work Package of MARSITE project gathers 9 research groups to study earthquake-induced landslides focusing on two sub-regional areas of high interest. First, the Cekmece-Avcilar peninsula, located westwards of Istanbul, is a highly urbanized concentrated landslide prone area, showing high susceptibility to both rainfalls while affected by very significant seismic site effects. Second, the off-shore entrance of the Izmit Gulf, close to the termination of the surface rupture of the 1999 earthquake

  5. Atmospheric polychlorinated biphenyl (pcb) inputs to a coastal city near the Marmara Sea.

    PubMed

    Günindi, Manolya; Tasdemir, Yücel

    2010-12-01

    Recent studies have shown that polychlorinated biphenyl (PCB) levels are high in coastal sites. Various types of deposition events, including dry deposition, air-water exchange and wet deposition, were analyzed as part of the study to illustrate the pollution level. The atmospheric levels and deposition mechanisms of 82 PCBs were investigated in Mudanya, a coastal city in Turkey. A total of 175 samples and 112 blanks were collected. Air-water exchange and particle phase dry deposition fluxes were 120 ± 90 ng/m(2)-d and 125 ± 160 ng/m(2)-d, respectively. The wet-dry deposition sampler (WDDS) consisted of two reservoirs, wet and dry. Collected with the WDDS, the dry deposition flux was 21 ± 20 ng/m(2)-d, and the wet deposition fluxes (during the rainy period) were 145 ± 130 ng/m(2)-d and 195 ± 270 ng/m(2)-d for the dissolved and particulate phases, respectively. Mass transfer coefficients (MTCs), dry deposition velocities and washout ratios were calculated and compared with the literature values.

  6. Radioactivity levels in mussels and sediments of the Golden Horn by the Bosphorus Strait, Marmara Sea.

    PubMed

    Kılıç, Önder; Belivermiş, Murat; Gözel, Furkan; Carvalho, Fernando P

    2014-09-15

    The Golden Horn is an estuary located in the center of İstanbul receiving freshwater discharges from two creeks and connecting to the Bosphorus Strait. Activity concentrations of natural and artificial radionuclides were determined in mussels (Mytilus galloprovincialis) and sediments from the Golden Horn sampled in February 2012. Mean activity concentrations of (137)Cs, (40)K, (226)Ra, (228)Ra, (210)Po and (210)Pb in the mussels were determined at 1.03±0.23, 389±41.6, 2.61±1.23, not detected (ND), 91.96±37.88 and 11.48±4.85 Bq kg(-1), respectively. In sediments, it was observed that (137)Cs, (40)K, (226)Ra, (228)Ra, (210)Po and (210)Pb activity concentrations in<63 μm particle fraction of sediment were generally higher than those determined in mussels. Po-210 and (210)Po/(210)Pb ratios in mussels from the Golden Horn were much lower than in mussels from other coastal regions and this was related to low plankton productivity and eutrophication of the Golden Horn.

  7. Perceptual inference.

    PubMed

    Aggelopoulos, Nikolaos C

    2015-08-01

    Perceptual inference refers to the ability to infer sensory stimuli from predictions that result from internal neural representations built through prior experience. Methods of Bayesian statistical inference and decision theory model cognition adequately by using error sensing either in guiding action or in "generative" models that predict the sensory information. In this framework, perception can be seen as a process qualitatively distinct from sensation, a process of information evaluation using previously acquired and stored representations (memories) that is guided by sensory feedback. The stored representations can be utilised as internal models of sensory stimuli enabling long term associations, for example in operant conditioning. Evidence for perceptual inference is contributed by such phenomena as the cortical co-localisation of object perception with object memory, the response invariance in the responses of some neurons to variations in the stimulus, as well as from situations in which perception can be dissociated from sensation. In the context of perceptual inference, sensory areas of the cerebral cortex that have been facilitated by a priming signal may be regarded as comparators in a closed feedback loop, similar to the better known motor reflexes in the sensorimotor system. The adult cerebral cortex can be regarded as similar to a servomechanism, in using sensory feedback to correct internal models, producing predictions of the outside world on the basis of past experience.

  8. Seafloor slow vertical displacement inferred by sea bottom pressure measurements in shallow water: an application to the Campi Flegrei volcanic area

    NASA Astrophysics Data System (ADS)

    Chierici, Francesco; Pignagnoli, Luca; Iannaccone, Giovanni; Guardato, Sergio; Locritani, Marina; Embriaco, Davide; Donnarumma, Gian Paolo; La Rocca, Adriano; Pinto, Salvatore; Beranzoli, Laura

    2016-04-01

    The vertical component of sea floor displacement in tectonic or volcanically active areas can be observed using sea bottom pressure recorders. These measurements are usually acquired in areas affected by strong dynamics with large vertical displacement and in deep water, where the noise induced by the sea state is low. Under these conditions the contribution of the variation of sea water density and the contribution of the instrumental drift - a typical feature of the bottom pressure recorders - can be negligible. We have developed a new methodology to monitor vertical sea floor displacement both in areas with small and slow deformation, and in shallow water. We take advantage of bottom pressure recorder data, augmented with ancillary sea level, barometric and water physical parameters measurements. We have applied this method to the data collected by a bottom pressure recorder deployed at 100 m w.d. in the Campi Flegrei Caldera as part of CUMAS multiparameter monitoring system. During several months of 2011 we have observed a small uplift episode related to the bradiseismic activity of the area. These observations are compatible with other geodetic data recorded in the region and provide unprecedented measurements of the vertical deformation in the marine area.

  9. Global ice volume during MIS 3 inferred from a sea-level analysis of sedimentary core records in the Yellow River Delta

    NASA Astrophysics Data System (ADS)

    Pico, Tamara; Mitrovica, Jerry X.; Ferrier, Ken L.; Braun, Jean

    2016-11-01

    Estimates of global ice volume during the glacial phase of the most recent ice age cycle are characterized by significant uncertainty, reflecting the relative paucity of geological constraints on sea level relevant to this time interval. For example, during the middle stages of Marine Isotope Stage 3, published estimates of peak global mean sea level (GMSL) relative to the present range from -25 m to -87 m. The large uncertainty in GMSL at MIS 3 has significant implications for estimates of the rate of ice growth in the period leading to the Last Glacial Maximum (∼26 ka). We refine estimates of global ice volume during MIS 3 by employing sediment cores in the Bohai and Yellow Sea that record a migration of the paleoshoreline at ∼50-37 ka through a transition from marine to brackish conditions. In particular, we correct relative sea level at these sites for contamination due to glacial isostatic adjustment using a sea-level calculation that includes a gravitationally self-consistent treatment of sediment redistribution and compaction, and estimate a peak global mean sea level of -38 ± 7 m during the interval 50-37 ka. With suitable sedimentary core records, the approach described herein can be extended to refine existing constraints on global ice volume across the entire glacial period.

  10. The stability of gas hydrate field in the northeastern continental slope of Sakhalin Island, Sea of Okhotsk, as inferred from analysis of heat flow data and its implications for slope failures

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Lee, S.; Jin, Y.; Baranov, B.; Obzhirov, A.; Salomatin, A.; Shoji, H.

    2012-12-01

    The sudden release of methane in shallow water due to ocean warming and/or sea level drop, leading to extensive mass wasting at continental margins, has been suggested as a possible cause of global climate change. In the northeastern continental slope of the Sakhalin Island (Sea of Okhotsk), numerous gas hydrate-related manifestations occur, including hydroacoustic anomaly (gas flare) in the water column, pockmarks and mounds on the seafloor, seepage structures and bottom-simulating reflectors (BSRs). The gas hydrate found at 385 mbsl represents the shallowest occurrence ever recorded in the Okhotsk Sea. In this study, we modeled the gas hydrate stability zone (GHSZ) using methane gas composition, water temperature and geothermal gradient to see if it is consistent with the observed depth of BSR. An important distinction can be made between the seafloor containing seepage features and normal seafloor in terms of their thermal structure. The depth of BSR matches well with the base of GHSZ estimated from the background heat flow (geothermal gradient). A large slope failure feature is found in the northern Sakhalin continental slope. We explore the possibility that this failure was caused by gas hydrate dissociation, based on the past climate change history and inference from the GHSZ modeling. Prediction of the natural landslide is difficult; however, new stratigraphic evidence from subbottom profiles suggests that the landslide occurred at 20 ka which is roughly consistent with the period of sea level drop during the Last Glacial Maximum. Furthermore, this region has witnessed a rapid sea water temperature increase (~0.6°C) in the last 50 years. If such a trend continues, additional slope failure can be expected in the near future in this region.

  11. Rupture Directivity Effect on the Probabilistic Seismic Hazard Maps in the Marmara Region, Turkey

    NASA Astrophysics Data System (ADS)

    Spagnuolo, E.; Akinci, A.; Herrero, A.; Pucci, S.

    2014-12-01

    In this study, we attempt to incorporate the rupture directivity effects into seismic hazard analysis in the Marmara region, Turkey. We introduce information about the fault segments by focusing on the fault rupture characteristics, near source directivity effects and its influence on the probabilistic seismic hazard analyses (PSHA) accounting for the azimuthal variations of the ground motion spatial distribution. An analytical model developed by Spudich and Chiou (2008) is used as a corrective factor that modifies four ground motion predictive equations (GMPEs) (Abrahamson & Silva 2008; Boore & Atkinson 2008; Campbell & Bozorgnia 2008; Chiou &Youngs 2008) and accounts for rupture related parameters that generally lump together into the term directivity effect. In this paper, we only use the relation calibrated for the Abrahamson & Silva (2008) and Boore & Atkinson (2008). In order to evaluate the impact of the rupture directivity effects to ground motion hazard in the near source we attempt to calculate the fault-based probabilistic seismic hazard maps (PSHA) of mean Peak Ground Acceleration (PGA) having 10% probability of exceedance in 50 years on rock site condition. Therefore the PSHMs for the Marmara region is produced incorporating detailed knowledge of active faulting and tectonic rates in earthquake recurrence models using the available database and the most innovative approaches. In order to test the impact of the corrective factor on seismic hazard we first considered its effect on a normal fault and on a strike slip fault as a function of magnitude. Seismic hazard is given in terms of Spectral Acceleration (SA) at seven different periods. We also report the percentage ratio between the seismic hazards computed with the directivity model and without it, over the seismic hazard resulting from the standard practice. Finally, we improve the seismic hazard maps in the near fault source incorporating the directivity effects in the ground motion prediction in

  12. Statistical Inference

    NASA Astrophysics Data System (ADS)

    Khan, Shahjahan

    Often scientific information on various data generating processes are presented in the from of numerical and categorical data. Except for some very rare occasions, generally such data represent a small part of the population, or selected outcomes of any data generating process. Although, valuable and useful information is lurking in the array of scientific data, generally, they are unavailable to the users. Appropriate statistical methods are essential to reveal the hidden "jewels" in the mess of the row data. Exploratory data analysis methods are used to uncover such valuable characteristics of the observed data. Statistical inference provides techniques to make valid conclusions about the unknown characteristics or parameters of the population from which scientifically drawn sample data are selected. Usually, statistical inference includes estimation of population parameters as well as performing test of hypotheses on the parameters. However, prediction of future responses and determining the prediction distributions are also part of statistical inference. Both Classical or Frequentists and Bayesian approaches are used in statistical inference. The commonly used Classical approach is based on the sample data alone. In contrast, increasingly popular Beyesian approach uses prior distribution on the parameters along with the sample data to make inferences. The non-parametric and robust methods are also being used in situations where commonly used model assumptions are unsupported. In this chapter,we cover the philosophical andmethodological aspects of both the Classical and Bayesian approaches.Moreover, some aspects of predictive inference are also included. In the absence of any evidence to support assumptions regarding the distribution of the underlying population, or if the variable is measured only in ordinal scale, non-parametric methods are used. Robust methods are employed to avoid any significant changes in the results due to deviations from the model

  13. Statistical Inference

    NASA Astrophysics Data System (ADS)

    Khan, Shahjahan

    Often scientific information on various data generating processes are presented in the from of numerical and categorical data. Except for some very rare occasions, generally such data represent a small part of the population, or selected outcomes of any data generating process. Although, valuable and useful information is lurking in the array of scientific data, generally, they are unavailable to the users. Appropriate statistical methods are essential to reveal the hidden “jewels” in the mess of the row data. Exploratory data analysis methods are used to uncover such valuable characteristics of the observed data. Statistical inference provides techniques to make valid conclusions about the unknown characteristics or parameters of the population from which scientifically drawn sample data are selected. Usually, statistical inference includes estimation of population parameters as well as performing test of hypotheses on the parameters. However, prediction of future responses and determining the prediction distributions are also part of statistical inference. Both Classical or Frequentists and Bayesian approaches are used in statistical inference. The commonly used Classical approach is based on the sample data alone. In contrast, increasingly popular Beyesian approach uses prior distribution on the parameters along with the sample data to make inferences. The non-parametric and robust methods are also being used in situations where commonly used model assumptions are unsupported. In this chapter,we cover the philosophical andmethodological aspects of both the Classical and Bayesian approaches.Moreover, some aspects of predictive inference are also included. In the absence of any evidence to support assumptions regarding the distribution of the underlying population, or if the variable is measured only in ordinal scale, non-parametric methods are used. Robust methods are employed to avoid any significant changes in the results due to deviations from the model

  14. Phylogeography of Tetrancistrum nebulosi (Monogenea, Dactylogyridae) on the host of mottled spinefoot (Siganus fuscescens) in the South China Sea, inferred from mitochondrial COI and ND2 genes.

    PubMed

    Wang, Ming; Yan, Shuai; Brown, Christopher L; Shaharom-Harrison, Faizah; Shi, Su-Fen; Yang, Ting-Bao

    2016-11-01

    To examine the phylogeographical pattern of Tetrancistrum nebulosi (Monogenea, Dactylogyridae) in the South China Sea, fragments of mitochondrial cytochrome c oxidase subunit I and NADH dehydrogenase subunit 2 genes were obtained for 220 individuals collected from 8 localities along the southeast coast of China and 1 locality in Terengganu, Malaysia. Based on these two genes, two and three distinct clades with geographic signals were revealed on the phylogenetic trees respectively. The divergence between these clades was estimated to occur in the late Pleistocene. Analysis of molecular variance and pairwise FST suggested a high rate of gene flow among individuals sampled from the Chinese coast, but with obvious genetic differentiation from the Malaysian population. Mismatch distribution and neutrality tests indicated that the T. nebulosi population experienced expansion in Pleistocene low sea level periods. Vicariance was considered to account for the genetic divergence between Chinese and Malaysian populations, while sea level fluctuations and mainland-island connections during glacial cycles were associated with the slight genetic divergence between the populations along the mainland coast of China and those off Sanya. On the contrary, oceanographic circulations and host migration could lead to genetic homogeneity of populations distributed along the mainland coast of China.

  15. Exploiting UV lambertian equivalent reflectivity data to infer changes in cloudiness and sea-ice in southern middle and high latitudes

    NASA Astrophysics Data System (ADS)

    Damiani, Alessandro

    2015-04-01

    Lambertian equivalent reflectivity (LER) ultraviolet (UV) data are routinely retrieved from many satellite-based instruments. Besides their original primarily function related to the retrieval of the ozone data, they also demonstrated to be useful as a cloudiness proxy comparable with data recorded from ground-based instruments, as well as for tracking ice/snow changes at high latitudes. LER time series spanning more than three decades can be retrieved from TOMS/OMI instruments although concerns related to the EP TOMS scan mirror degradation exist. Therefore, recently additional multi-satellite-based LER datasets have been created from SBUV instruments in the frame of the NASA MEaSUREs Program (Herman et al. 2013). In this presentation we report some recent applications of both datasets over southern middle and high latitudes focusing on cloudiness, surface UV and sea-ice. LER data have been analyzed over eight locations spanning from about 18° (north of Chile) to 62° S (Antarctic peninsula) covering years 1978-2011. Generally the distribution of the reflectivity of both TOMS datasets is similar. On the other hand, OMI LER data differ from TOMS ones in almost all locations. Daily CMF values from ground-based global solar irradiance measurements have been compared with OMI LER-based CMF data. The northernmost and southernmost locations characterized by prevalent clear sky and winter snow conditions, respectively, showed the worse agreement while the other stations showed a better correlation. For one location clear sky ground UV index values for have been estimated for years 1979-2011 by means of an empirical reconstruction model based on data recorded by a multichannel radiometer. Then, we exploit satellite LER data for computing actual surface UV by correcting clear sky UV with LER-based CMF data. Besides we also evaluated the cloud cover and the sea ice influence on the reflectivity in the Southern Ocean by comparing the MEaSUREs LER dataset with satellite

  16. Contribution of Asian dust and volcanic material to the western Philippine Sea over the last 220 kyr as inferred from grain size and Sr-Nd isotopes

    NASA Astrophysics Data System (ADS)

    Jiang, Fuqing; Zhou, Ye; Nan, Qingyun; Zhou, Yu; Zheng, Xufeng; Li, Tiegang; Li, Anchun; Wang, Hongli

    2016-09-01

    Asian dust and volcanogenic materials are two major components in the northwestern Pacific. Quantitatively distinguishing them and estimating their mass accumulation rates (MARs) are very important for understanding regional and global climate change. Here we present the grain-size composition of detrital sediments and the radiogenic strontium (Sr) and neodymium (Nd) isotopic compositions of different grain-size fractions of detrital sediments that were recovered from the western Philippine Sea. These new records show that the different grain-size distributions can be associated with 1) Asian dust from the western and central Chinese deserts and Chinese loess and 2) volcanogenic materials that were derived from the Luzon Islands. The MARs of this Asian dust and volcanic materials are obtained by using Weibull-function fitting. The MARs of Asian dust and volcanic materials are coupled with the glacial-interglacial cycle; these values are found to have been higher and more variable during the glacial period than during the interglacial period. We argue that the strengthening aridity of the Asian continent, which is connected to solar insolation and ice volume variations from orbital eccentricity, constitutes an important mechanism that drives the high MARs of glacial dust in the western Philippine Sea. The internal positive feedback of dust may be another important mechanism. The significant increase in volcanic material during the glacial period was caused by sea level changes, which were driven by the ice volume and solar insolation at high latitudes, and by strengthened precipitation from the El Niño/Southern Oscillation (ENSO), which is driven by orbital eccentricity and precession cycles on the Luzon Islands.

  17. A 200-Year Record of Interannual SST and pH Variability from the Lesser Antilles (Caribbean Sea, North Atlantic) Inferred from a Siderastrea Siderea Reef Coral

    NASA Astrophysics Data System (ADS)

    Douville, E.; Paterne, M.; Feuillet, N.; Noury, C.; Bordier, L.; Thil, F.

    2014-12-01

    Global warming and ocean acidification caused by the rising levels of anthropogenic CO2 in the atmosphere need to be better constrained by long-term studies of high resolution natural archives, especially at inter-annual and decadal scales. In the framework of the French INSU program LEFE/CYBER ACID-Antilles, here we developed a 200-year long interannual time series of sea surface temperature and pH based on the geochemical composition of tropical reef forming coral. The selected tropical coral called CHANCEL-1 is a colony of genus Siderastrea Siderea which was collected in 2008 from a living micro-atoll off Martinique in the Lesser Antilles, facing the eastern side of the Caribbean Sea. The colony of 1-meter extension presents a mean growth rate of 4 - 5 mm/yr. Along the growth axis, we measured the boron isotopic composition (delta11B) and trace element ratios (Li/Mg, Sr/Ca), which reveal a progressive decrease of the surface water pH and increase of temperature during the past 200 years. These observations cooperate the anthropogenic forcing, i.e. rising atmospheric CO2 and rising sea surface temperatures due to global warming. However, other processes apparently affect the geochemical records, as indicated by sub-decadal variations of pH and temperature reconstruction overprinting the long term global trend. Possible drivers of such most likely regional variability might be decadal changes of oceanographic conditions (upwelling, freshwater runoff, seawater masse changes, etc.) as well as species dependent biological controls.

  18. A strong ‘filter’ effect of the East China Sea land bridge for East Asia’s temperate plant species: inferences from molecular phylogeography and ecological niche modelling of Platycrater arguta (Hydrangeaceae)

    PubMed Central

    2014-01-01

    Background In East Asia, an increasing number of studies on temperate forest tree species find evidence for migration and gene exchange across the East China Sea (ECS) land bridge up until the last glacial maximum (LGM). However, it is less clear when and how lineages diverged in this region, whether in full isolation or in the face of post-divergence gene flow. Here, we investigate the effects of Quaternary changes in climate and sea level on the evolutionary and demographic history of Platycrater arguta, a rare temperate understorey shrub with disjunct distributions in East China (var. sinensis) and South Japan (var. arguta). Molecular data were obtained from 14 P. arguta populations to infer current patterns of molecular structure and diversity in relation to past (Last Interglacial and Last Glacial Maximum) and present distributions based on ecological niche modelling (ENM). A coalescent-based isolation-with-migration (IM) model was used to estimate lineage divergence times and population demographic parameters. Results Combining information from nuclear/chloroplast sequence data with nuclear microsatellites, our IM analyses identify the two varieties as genetically distinct units that evolved in strict allopatry since the mid-Pleistocene, c. 0.89 (0.51–1.2) Ma. Together with Bayesian Skyeline Plots, our data further suggest that both lineages experienced post-divergence demographic growth, followed by refugial isolation, divergence, and in the case of var. arguta post-glacial admixture. However, past species distribution modelling indicates that the species’ overall distribution has not greatly changed over the last glacial cycles. Conclusions Our findings highlight the important influence of ancient sea-level changes on the diversification of East Asia’s temperate flora. Implicitly, they challenge the notion of general temperate forest expansion across the ECS land bridge, demonstrating instead its ‘filter’ effect owing to an unsuitable environment

  19. Implementing the effect of the rupture directivity on PSHA maps: Application to the Marmara Region (Turkey)

    NASA Astrophysics Data System (ADS)

    Herrero, Andre; Spagnuolo, Elena; Akinci, Aybige; Pucci, Stefano

    2016-04-01

    In the present study we attempted to improve the seismic hazard assessment taking into account possible sources of epistemic uncertainty and the azimuthal variability of the ground motions which, at a particular site, is significantly influenced by the rupture mechanism and the rupture direction relative to the site. As a study area we selected Marmara Region (Turkey), especially the city of Istanbul which is characterized by one of the highest levels of seismic risk in Europe and the Mediterranean region. The seismic hazard in the city is mainly associated with two active fault segments which are located at about 20-30 km south of Istanbul. In this perspective first we proposed a methodology to incorporate this new information such as nucleation point in a probabilistic seismic hazard analysis (PSHA) framework. Secondly we introduced information about those fault segments by focusing on the fault rupture characteristics which affect the azimuthal variations of the ground motion spatial distribution i.e. source directivity effect and its influence on the probabilistic seismic hazard analyses (PSHA). An analytical model developed by Spudich and Chiou (2008) is used as a corrective factor that modifies the Next Generation Attenuation (NGA, Power et al. 2008) ground motion predictive equations (GMPEs) introducing rupture related parameters that generally lump together into the term directivity effect. We used the GMPEs as derived by the Abrahamson and Silva (2008) and the Boore and Atkinson (2008); our results are given in terms of 10% probability of exceedance of PSHA (at several periods from 0.5 s to 10 s) in 50 years on rock site condition; the correction for directivity introduces a significant contribution to the percentage ratio between the seismic hazards computed using the directivity model respect to the seismic hazard standard practice. In particular, we benefited the dynamic simulation from a previous study (Aochi & Utrich, 2015) aimed at evaluating the

  20. Moment Magnitude Determination for Marmara Region-Turkey Using Displacement Spectra

    NASA Astrophysics Data System (ADS)

    Köseoǧlu Küsmezer, Ayşegül; Meral Özel, Nurcan; Barış, Å.žErif; Üçer, S. Balamir; Ottemöller, Lars

    2010-05-01

    The main purpose of the study is to determine moment magnitude Mω using displacement source spectra of earthquakes occurred in Marmara Region. The region is the most densely populated and fast-developing part of Turkey, bounded by 39.0°N to 42.0°N and 26.0°E to 32.0°E, and have experienced major earthquake disasters during the last four centuries with destructive earthquakes and probabilistic seismic hazard studies shows that the region have significant probability of producing M>7 earthquake within the next years. Seismic moment is a direct measurement of earthquake size (rupture area and static displacement) and does not saturate, spectral analysis at local distances is a very useful method which allows the reliable determination of seismic moment and moment magnitude. We have used converging grid search method developed by L. Ottemöller, and J. Havskov, 2008 for the automatic determination of moment magnitude for local distances. For data preperation; the time domain signal of S waves were extracted from the vertical component seismograms.Data was transformed from time to frequency domain by applying the standart fast fourier transform (fft). Source parameters and moment magnitudes of earthquakes are determined by applying spectral fitting procedure to classical Brune's model. The method is first manually and then automatically performed on the source spectrum of S waves within 20 sec. Mo and fc (Aki;1967, and Brune;1970) were determined by using the method which the model space is divided into a grid and the error function detected for all grid points. A smaller grid with denser spacing around the best solution is generated with an iterative procedure. The moment magnitudes of the earthquakes have been calculated according to the scale of Kanamori (1977) and Hanks and Kanamori (1979). A data set of 279 events recorded on broadband velocity seismograms extracted from KOERI (Kandilli Observatory and Earthquake Research Institute) seismic network were

  1. Electrical resistivity structure under the western Cosmonauts Sea at the continental margin of East Antarctica inferred via a marine magnetotelluric experiment

    NASA Astrophysics Data System (ADS)

    Matsuno, Tetsuo; Nogi, Yoshifumi; Seama, Nobukazu

    2015-06-01

    The western Cosmonauts Sea, off the coast of East Antarctica, was a site of rifting of the Gondwana supercontinent and subsequent early seafloor spreading. To improve our understanding of the breakup of Gondwana, we conducted a marine magnetotelluric experiment to determine the electrical resistivity structure within the uppermost several hundred kilometers beneath the western Cosmonauts Sea. Magnetotelluric response functions at two sites, obtained after considering possible influences of non-plane magnetic field sources, suggest that these responses include distortions by topographic variations and conductive anomalies around the observation sites. Three-dimensional forward modeling confirmed that these distortions due to topographic variations and a thin (∼2-km thick) conductive layer immediately under the sites (mostly sediments) are severe. Furthermore, three-dimensional forward modeling to investigate the resistivity structure at deeper depths revealed an upper resistive layer (≥300 Ω-m), with a thickness of <100 km, and an underlying conductive half-space (∼10 Ω-m). The upper resistive layer and the underlying conductive structure most likely represent dry and water/melt-rich oceanic upper mantle, respectively. The upper resistive layer may be thinner than anticipated under the old seafloor of the study area (likely >90 Ma), and may suggest a conductive anomaly in the upper mantle produced by mantle convection and/or upwelling.

  2. Metabolic strategies of free-living and aggregate-associated bacterial communities inferred from biologic and chemical profiles in the Black Sea suboxic zone.

    PubMed

    Fuchsman, Clara A; Kirkpatrick, John B; Brazelton, William J; Murray, James W; Staley, James T

    2011-12-01

    The Black Sea is a permanently anoxic basin with a well-defined redox gradient. We combine environmental 16S rRNA gene data from clone libraries, terminal restriction fragment length polymorphisms, and V6 hypervariable region pyrosequences to provide the most detailed bacterial survey to date. Furthermore, this data set is informed by comprehensive geochemical data; using this combination of information, we put forward testable hypotheses regarding possible metabolisms of uncultured bacteria from the Black Sea's suboxic zone (microaerophily, nitrate reduction, manganese cycling, and oxidation of methane, ammonium, and sulfide). Dominant bacteria in the upper suboxic zone included members of the SAR11, SAR324, and Microthrix groups and in the deep suboxic zone included members of BS-GSO-2, Marine Group A, and SUP05. A particulate fraction (30 μm filter) was used to distinguish between free-living and aggregate-attached communities in the suboxic zone. The particulate fraction contained greater diversity of V6 tag sequences than the bulk water samples. Lentisphaera, Epsilonproteobacteria, WS3, Planctomycetes, and Deltaproteobacteria were enriched in the particulate fraction, whereas SAR11 relatives dominated the free-living fraction. On the basis of the bacterial assemblages and simple modeling, we find that in suboxic waters, the interior of sinking aggregates potentially support manganese reduction, sulfate reduction, and sulfur oxidation.

  3. Heavy metal deposition in moss samples from east and south Marmara region, Turkey.

    PubMed

    Coskun, Mahmut; Cayir, Akin; Coskun, Munevver; Kilic, Onder

    2011-03-01

    A survey of atmospheric heavy metal deposition in the east and south Marmara region, Turkey was carried out in September 2004. For this purpose, moss samples (Hypnum cupressiforme) were collected in a systematic network of 125 sites. Concentrations of the elements (Al, B, Ba, Ca, Cd, Fe, Co, Cr, Cu, K, Li, Mn, Na, Ni, Pb, Sr, Mg, Ti, and Zn) in the moss were used as an indication of the level of air pollution in the region. Significant differences in heavy metal concentrations, especially for Pb, Cd, Cu, and Zn, were recorded in the moss samples collected around industrialized and heavily populated cities (Istanbul, Bursa, Bandırma, Kocaeli, Biga-Çan) and in an abandoned lead-mining area (Balıkesir-Balya). A map of the spatial distribution of each element in the region was plotted, and enrichment factors were calculated. VARIMAX principal component analysis was applied to the data obtained, and five different components were obtained. The results showed that Pb, Cu, Cd, and Zn derived from anthropogenic and industrial sources while other elements came mostly from natural sources.

  4. Flow path of the 1993 Hokkaido-Nansei-oki earthquake seismoturbidite, suthern margin of the Japan sea north basin, inferred from anisotropy of magnetic susceptibility

    USGS Publications Warehouse

    Abdeldayem, A.L.; Ikehara, K.; Yamazaki, T.

    2004-01-01

    A magnetic fabric analysis has been carried out on standard cube samples from one gravity and three multiple cores extracted from the Shiribeshi trough and Okushiri basin in the southern margin of the Japan sea north basin. It is aimed at tracing the flow path of turbidites that are assumed to have deposited in response to the 1993 Hokkaido-Nansei-oki earthquake. Magnetic remanence was used for reorientation to the geographic coordinates. Magnetomineralogical investigations including low-temperature magnetometry, magnetic hysteresis loops and isothermal remanent magnetization (IRM) acquisition experiments indicate that pseudosingle domain to multidomain magnetite is the principal magnetic carrier and is, therefore, capable of providing reliable anisotropy of magnetic susceptibility (AMS) palaeocurrent direction estimates. A well-developed near-horizontal magnetic foliation and minimum susceptibility axes lying close to vertical are recorded at all sites reflecting an original depositional fabric. Clearly defined magnetic lineation was observed at all sites and is considered to reflect the palaeocurrent direction. Down-core changes of susceptibility and key AMS parameters show good correspondence to occurrences of turbidite layers marking the increase of input of influx materials. In agreement with results from recent marine surveys and IZANAGI side-scan sonar images, an NNE transportation trend has been estimated for sediments at sites from the Shiribeshi trough with a possible depositing path initiating from the slope bounding the south and southeastern margin down to the trough floor. Similarly, a SSE palaeocurrent direction has been estimated for sediments from the Okushiri basin with evidence for a relatively strong transporting current flowing through the canyons along the steep slope bounding the north and northeastern margins of the basin. The present results agree with the view that slope failure is the most probable mechanism for the down-slope transport

  5. Flow path of the 1993 Hokkaido-Nansei-oki earthquake seismoturbidite, southern margin of the Japan sea north basin, inferred from anisotropy of magnetic susceptibility

    NASA Astrophysics Data System (ADS)

    Abdeldayem, A. L.; Ikehara, K.; Yamazaki, T.

    2004-04-01

    A magnetic fabric analysis has been carried out on standard cube samples from one gravity and three multiple cores extracted from the Shiribeshi trough and Okushiri basin in the southern margin of the Japan sea north basin. It is aimed at tracing the flow path of turbidites that are assumed to have deposited in response to the 1993 Hokkaido-Nansei-oki earthquake. Magnetic remanence was used for reorientation to the geographic coordinates. Magnetomineralogical investigations including low-temperature magnetometry, magnetic hysteresis loops and isothermal remanent magnetization (IRM) acquisition experiments indicate that pseudo-single domain to multidomain magnetite is the principal magnetic carrier and is, therefore, capable of providing reliable anisotropy of magnetic susceptibility (AMS) palaeocurrent direction estimates. A well-developed near-horizontal magnetic foliation and minimum susceptibility axes lying close to vertical are recorded at all sites reflecting an original depositional fabric. Clearly defined magnetic lineation was observed at all sites and is considered to reflect the palaeocurrent direction. Down-core changes of susceptibility and key AMS parameters show good correspondence to occurrences of turbidite layers marking the increase of input of influx materials. In agreement with results from recent marine surveys and IZANAGI side-scan sonar images, an NNE transportation trend has been estimated for sediments at sites from the Shiribeshi trough with a possible depositing path initiating from the slope bounding the south and southeastern margin down to the trough floor. Similarly, a SSE palaeocurrent direction has been estimated for sediments from the Okushiri basin with evidence for a relatively strong transporting current flowing through the canyons along the steep slope bounding the north and northeastern margins of the basin. The present results agree with the view that slope failure is the most probable mechanism for the down-slope transport

  6. Plio-Pleistocene Bering Sea - North Pacific Ocean Circulation Dynamics Inferred from Sediment Source Changes at the Meiji Drift, Northwest Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Vanlaningham, S.; Haley, B.; Hillier, S.; Alizai, A. H.

    2010-12-01

    The Pliocene is an interesting time in Earth’s history because it was warmer than today and could serve as an analog for how Earth might behave in response to future warming. It also precedes the onset of Northern Hemisphere glaciation that started ~3 million years ago. Yet it remains an open question whether closing of the Isthmus of Panama and opening of the Bering Strait impacted ocean circulation and climate 4-5 Ma. A large drift deposit in the northwest Pacific known as the Meiji Drift may hold clues about the possible impact of the Bering gateway on Pliocene climate dynamics in the Northern Hemisphere. It was previously demonstrated that the Meiji Drift is sensitive to changes at the Bering Strait, at least over the last 150 ka. This work investigates Plio-Pleistocene changes at the Meiji Drift using mineralogical and bulk sediment Nd isotopic techniques applied to the terrigenous fraction. Quantitative mineralogy of Meiji Drift sediment shows significant changes in quartz, plagioclase, K-feldspar, and amphibole at 5 Ma as well as around 1.5-2 Ma. Nd isotopic data show a transition from epsilon Nd values of +8 at 5 Ma to +1 by 3 Ma. These data suggest that circum-Pacific arc rocks were the dominant source of terrigenous sediment to the Meiji Drift around 5 Ma. From 5 to 3 Ma the sediment became progressively mixed with more continental-like source rocks. It is likely that increased flow from the Bering Sea (dominated by detritus from the Yukon River) to the North Pacific occurred ~5 Ma. This coincides with when the Bering Strait likely first opened with southward flow. But after the onset of Northern Hemisphere glaciation the sediment sources to the Meiji Drift likely began to oscillate at higher frequency with the opening and closing of the Bering gateway on glacial-interglacial timescales. Higher resolution work on the detrital fraction of the Meiji Drift will better constrain the timing, magnitude, and direction of ocean circulation changes in the Bering

  7. Inferences from the horizontal distribution of dab Limanda limanda (L.) and flounder Platichthys flesus (L.) larvae in the southeastern North Sea

    NASA Astrophysics Data System (ADS)

    Campos, Wilfredo L.; Kloppmann, Matthias; von Westernhagen, Hein

    The horizontal distribution of dab, Limanda limanda L., and flounder, Platichthys flesus L., larvae in the southeastern North Sea was studied during the winter-spring period of 1992. Dab larvae comprised 51% of all fish larvae recorded and increased in abundance from February to late April, with a mean overall larval density of 38.8 ind·m -2 during the study period. Flounder larvae comprised 10% of all fish larvae and were most abundant in late March with an average density of 12.5 ind·m -2. Highest larval concentrations for both species were observed in waters off the west Frisian coast and in the inner German Bight, consistent with previously reported egg concentrations. Correlation analyses indicated similar distributions of early (I & II) stage larvae, but dissimilar distribution patterns in later (III & IV) larval stages. This is consistent with known spawning locations and postlarval habitats for the two species. Vertical migration is proposed as a potential mechanism that may explain the observed stage-specific horizontal distributions. Apparent differences in relative growth between two high-density centres suggested that larval dynamics may be different in these areas.

  8. Carbon cycling in primary production bottle incubations: inferences from grazing experiments and photosynthetic studies using 14C and 18O in the Arabian Sea

    NASA Astrophysics Data System (ADS)

    Laws, Edward A.; Landry, Michael R.; Barber, Richard T.; Campbell, Lisa; Dickson, Mary-Lynn; Marra, John

    Estimates of photosynthesis based on the incorporation of 14C-labeled inorganic carbon into particulate carbon were compared to estimates of gross photosynthesis based on net O 2 production and the production of 18O2 from H218O during the US Joint Global Ocean Flux Study (US JGOFS) Arabian Sea process cruises. For samples incubated below the surface and at optical depths<3, the 14C uptake : gross photosynthesis ratio averaged 0.45±0.1. This result is in accord with theoretical considerations of the combined effects of the Mehler reaction, photorespiration, dark respiration, excretion, and grazing effects on the two estimates of photosynthesis. The 14C uptake : gross photosynthesis ratio was distinctly higher (0.62) for samples incubated at the surface. This result is likely due to UV light effects, since the O 2 and 14C incubations were done in quartz and polysulfone bottles, respectively. The 14C uptake : gross photosynthesis ratio was lower (0.31) for bottles incubated at optical depths>3. This result probably reflects an increase in the ratio of dark respiration to net photosynthesis in the vicinity of the compensation light level.

  9. Intercomparison of Satellite Derived Gravity Time Series with Inferred Gravity Time Series from TOPEX/POSEIDON Sea Surface Heights and Climatological Model Output

    NASA Technical Reports Server (NTRS)

    Cox, C.; Au, A.; Klosko, S.; Chao, B.; Smith, David E. (Technical Monitor)

    2001-01-01

    The upcoming GRACE mission promises to open a window on details of the global mass budget that will have remarkable clarity, but it will not directly answer the question of what the state of the Earth's mass budget is over the critical last quarter of the 20th century. To address that problem we must draw upon existing technologies such as SLR, DORIS, and GPS, and climate modeling runs in order to improve our understanding. Analysis of long-period geopotential changes based on SLR and DORIS tracking has shown that addition of post 1996 satellite tracking data has a significant impact on the recovered zonal rates and long-period tides. Interannual effects such as those causing the post 1996 anomalies must be better characterized before refined estimates of the decadal period changes in the geopotential can be derived from the historical database of satellite tracking. A possible cause of this anomaly is variations in ocean mass distribution, perhaps associated with the recent large El Nino/La Nina. In this study, a low-degree spherical harmonic gravity time series derived from satellite tracking is compared with a TOPEX/POSEIDON-derived sea surface height time series. Corrections for atmospheric mass effects, continental hydrology, snowfall accumulation, and ocean steric model predictions will be considered.

  10. Pre to Post-Bomb Seawater 14C History in the Gulf of Alaska Inferred From a Deep Sea Coral: Isididae sp.

    NASA Astrophysics Data System (ADS)

    Roark, B.; Guilderson, T. P.; Fallon, S.; Dunbar, R. B.; McCulloch, M.

    2006-12-01

    Deep-sea corals are an important archive of intermediate and deep-water variability, and provide the means to explore decadal to century-scale ocean dynamics in regions and time periods heretofore unexplored. We present a reconstruction of pre to post-bomb surface and interior water Δ14C based on analysis of deep-sea Isididae (bamboo) corals collected live at ~700 meters in June 2002 at Warwick Seamount, Gulf of Alaska. Concurrent isotope analyses of polyp/tissue and outermost portion of the hard horny proteinaceous gorgonin nodes compared with in situ dissolved inorganic carbon indicates that the gorgonin portion is derived exclusively from recently fixed/exported particulate organic carbon and thus a record of the surface water 14C/12C history. This is in contrast to the carbonate internode portion which is primarily derived from in situ dissolved inorganic carbon, and thus a record of the in situ 14C/12C. Radiocarbon analysis of gorgonin nodal sections captures the surface water D14C evolution. Pre-bomb values are -105‰ reaching a maximum of 100‰ before decreasing to collection values of 20‰. We anticipate that the post-bomb maximum will be in the early 1970s consistent with other mid to high latitude records and that the pre/post bomb transition initiates near 1956. If we utilize the gorgonin pre/post bomb transition as a tie-point and assume a linear growth rate the Isididae used in this study are 75- 125 years old. Carbonate Δ14C shows a 25‰ increase from -215 to -190‰ reflecting the penetration of bomb-14C in the sub-polar North Pacific. To place the carbonate time-series on a fixed timescale we determined the minor element chemistry and tested the inter-species reproducibility. The distribution of Sr is quite homogenous whereas Mg is not with higher Mg concentrations associated with centers of calcification. Age estimates using what appear to be annual Sr/Ca cycles, which we hypothesize are related to biomineralization cycles associated with a

  11. Anisakis simplex complex: ecological significance of recombinant genotypes in an allopatric area of the Adriatic Sea inferred by genome-derived simple sequence repeats.

    PubMed

    Mladineo, Ivona; Trumbić, Željka; Radonić, Ivana; Vrbatović, Anamarija; Hrabar, Jerko; Bušelić, Ivana

    2017-03-01

    The genus Anisakis includes nine species which, due to close morphological resemblance even in the adult stage, have previously caused many issues in their correct identification. Recently observed interspecific hybridisation in sympatric areas of two closely related species, Anisakis simplex sensu stricto (s.s.) and Anisakis pegreffii, has raised concerns whether a F1 hybrid generation is capable of overriding the breeding barrier, potentially giving rise to more resistant/pathogenic strains infecting humans. To assess the ecological significance of anisakid genotypes in the Adriatic Sea, an allopatric area for the two above-mentioned species, we analysed data from PCR-RFLP genotyping of the ITS region and the sequence of the cytochrome oxidase 2 (cox2) mtDNA locus to discern the parental genotype and maternal haplotype of the individuals. Furthermore, using in silico genome-wide screening of the A. simplex database for polymorphic simple sequence repeats or microsatellites in non-coding regions, we randomly selected potentially informative loci that were tested and optimised for multiplex PCR. The first panel of microsatellites developed for Anisakis was shown to be highly polymorphic, sensitive and amplified in both A. simplex s.s. and A. pegreffii. It was used to inspect genetic differentiation of individuals showing mito-nuclear mosaicism which is characteristic for both species. The observed low level of intergroup heterozygosity suggests that existing mosaicism is likely a retention of an ancestral polymorphism rather than a recent recombination event. This is also supported by allopatry of pure A. simplex s.s. and A. pegreffii in the geographical area under study.

  12. Twentieth century sea surface temperature and salinity variations at Timor inferred from paired coral δ18O and Sr/Ca measurements

    NASA Astrophysics Data System (ADS)

    Cahyarini, Sri Yudawati; Pfeiffer, Miriam; Nurhati, Intan Suci; Aldrian, Edvin; Dullo, Wolf-Christian; Hetzinger, Steffen

    2014-07-01

    The Indonesian Throughflow (ITF), which represents the global ocean circulation connecting the Pacific Warm Pool to the Indian Ocean, strongly influences the Indo-Pacific climate. ITF monitoring since the late 1990s using mooring buoys have provided insights on seasonal and interannual time scales. However, the absence of longer records limits our perspective on its evolution over the past century. Here, we present sea surface temperature (SST) and salinity (SSS) proxy records from Timor Island located at the ITF exit passage via paired coral δ18O and Sr/Ca measurements spanning the period 1914-2004. These high-resolution proxy based climate data of the last century highlights improvements and cautions when interpreting paleoclimate records of the Indonesian region. If the seasonality of SST and SSS is not perfectly in phase, the application of coral Sr/Ca thermometry improves SST reconstructions compared to estimates based on coral δ18O only. Our records also underline the importance of ocean advection besides rainfall on local SSS in the region. Although the El Niño/Southern Oscillation (ENSO) causes larger anomalies relative to the Indian Ocean Dipole (IOD), Timor coral-based SST and SSS records robustly correlate with IOD on interannual time scales, whereas ENSO only modifies Timor SST. Similarly, Timor SST and SSS are strongly linked to Indian Ocean decadal-scale variations that appear to lead Timor oceanographic conditions by about 1.6-2 years. Our study sheds new light on the complex signatures of Indo-Pacific climate modes on SST and SSS dynamics of the ITF. This article was corrected on 8 AUG 2014. See the end of the full text for details.

  13. Results of a multidisciplinary study in the Marmara Supersite, on-shore area: Büyükçekmece landslide

    NASA Astrophysics Data System (ADS)

    Coccia, Stella; Bigarré, Pascal; Ergintav, Semih; Ozel, Oguz; Yalcinkaya, Esref; Ozalabey, Serdar; Bourdeau, Céline; Martino, Salvatore; Lenti, Luca; Zucca, Francesco; Moro, Marco

    2016-04-01

    The MARsite project (Nov 2012-Avril 2016), one of the three SUPERSITE concept FP7 projects, deals with the definition of new directions in seismic hazard assessment through focused earth observation in the Marmara Supersite. This project gathers different research groups in a comprehensive monitoring activity developed in the Sea of Marmara Region. This region is one of the most densely populated parts of Europe and rated at high seismic risk level since the 1999 Izmit and Duzce devastating earthquakes. The 6th Work Package of MARsite project offered a very valuable frame to undertake simultaneous and complementary scientific investigations and studies to get deeper insight in the seismic and rainfall landslide topic, ranging from methodology to hazard assessment tool. This package focused on two sub-regional areas of high interest. First, the Avcilar-Beylikdüzü peninsula, located westwards of Istanbul, is a highly urbanized concentrated landslide prone area, showing high susceptibility to both rainfalls while affected by very significant seismic site effects. Second, the off-shore entrance of the Izmit Gulf, close to the termination of the surface rupture of the 1999 earthquake, that shows an important slump mass facing the Istanbul coastline. For the on-shore area, after refining the landslide inventory of the peninsula, one of the nine inventoried rototranslational landslides was chosen as pilot site, the Büyükçekmece landslide. This landslide has a continuous activity and a composite mechanism (including several secondary sliding surfaces); it moves at low velocity and involves sandy and clayey deposits of a local Cenozoic Succession damaging several infrastructures, such as buildings and roads. Various geophysical campaigns were carried out and then a field temporary multi-parameter monitoring was set up, composed of GPS-RTK, two seismic probes, thermometer, rain-gauge, moisture, etc.. Hyperspectral and Dinsar imagery technologies were also deployed to

  14. Gas hydrate identified in sand-rich inferred sedimentary section using downhole logging and seismic data in Shenhu area, South China Sea

    USGS Publications Warehouse

    Wang, Xiujuan; Lee, Myung W.; Collett, Timothy S.; Yang, Shengxiong; Guo, Yiqun; Wu, Shiguo

    2014-01-01

    Downhole wireline log (DWL) data was acquired from eight drill sites during China's first gas hydrate drilling expedition (GMGS-1) in 2007. Initial analyses of the acquired well log data suggested that there were no significant gas hydrate occurrences at Site SH4. However, the re-examination of the DWL data from Site SH4 indicated that there are two intervals of high resistivity, which could be indicative of gas hydrate. One interval of high resistivity at depth of 171–175 m below seafloor (mbsf) is associated with a high compressional- wave (P-wave) velocities and low gamma ray log values, which suggests the presence of gas hydrate in a potentially sand-rich (low clay content) sedimentary section. The second high resistivity interval at depth of 175–180 mbsf is associated with low P-wave velocities and low gamma values, which suggests the presence of free gas in a potentially sand-rich (low clay content) sedimentary section. Because the occurrence of free gas is much shallower than the expected from the regional depth of the bottom simulating reflector (BSR), the free gas could be from the dissociation of gas hydrate during drilling or there may be a local anomaly in the depth to the base of the gas hydrate stability zone. In order to determine whether the low P-wave velocity with high resistivity is caused by in-situ free gas or dissociated free gas from the gas hydrate, the surface seismic data were also used in this analysis. The log analysis incorporating the surface seismic data through the construction of synthetic seismograms using various models indicated the presence of free gas directly in contact with an overlying gas hydrate-bearing section. The occurrence of the anomalous base of gas hydrate stability at Site SH4 could be caused by a local heat flow conditions. This paper documents the first observation of gas hydrate in what is believed to be a sand-rich sediment in Shenhu area of the South China Sea.

  15. Influences of Local Sea-Surface Temperatures and Large-scale Dynamics on Monthly Precipitation Inferred from Two 10-year GCM-Simulations

    NASA Technical Reports Server (NTRS)

    Sud, Y. C.; Walker, G. K.; Zhou, Y.; Lau, W. K.-M.

    2007-01-01

    Two parallel sets of 10-year long: January 1, 1982 to December 31, 1991, simulations were made with the finite volume General Circulation Model (fvGCM) in which the model integrations were forced with prescribed sea-surface temperature fields (SSTs) available as two separate SST-datasets. One dataset contained naturally varying monthly SSTs for the chosen period, and the oth& had the 12-monthly mean SSTs for the same period. Plots of evaporation, precipitation, and atmosphere-column moisture convergence, binned by l C SST intervals show that except for the tropics, the precipitation is more strongly constrained by large-scale dynamics as opposed to local SST. Binning data by SST naturally provided an ensemble average of data contributed from disparate locations with same SST; such averages could be expected to mitigate all location related influences. However, the plots revealed: i) evaporation, vertical velocity, and precipitation are very robust and remarkably similar for each of the two simulations and even for the data from 1987-ENSO-year simulation; ii) while the evaporation increased monotonically with SST up to about 27 C, the precipitation did not; iii) precipitation correlated much better with the column vertical velocity as opposed to SST suggesting that the influence of dynamical circulation including non-local SSTs is stronger than local-SSTs. The precipitation fields were doubly binned with respect to SST and boundary-layer mass and/or moisture convergence. The analysis discerned the rate of change of precipitation with local SST as a sum of partial derivative of precipitation with local SST plus partial derivative of precipitation with boundary layer moisture convergence multiplied by the rate of change of boundary-layer moisture convergence with SST (see Eqn. 3 of Section 4.5). This analysis is mathematically rigorous as well as provides a quantitative measure of the influence of local SST on the local precipitation. The results were recast to

  16. Detailed structure of the Philippine Sea plate subducting along the Nankai Trough, western Japan, inferred from high-frequency seismic wave analysis

    NASA Astrophysics Data System (ADS)

    Furumura, T.; Padhy, S.; Maeda, T.

    2012-12-01

    A detailed structure of the subducting Philippine Sea plate (PHP) along the Nankai trough in western Japan was studied by analyzing waveforms recorded at dense Hi-net stations in Japan. It is well recognized that the waveforms from intraplate earthquakes dominate in high-frequency (f >1 Hz) signals due to the waveguide effect of the subducting slab (Furumura and Kennett, 2005; 2008). This results in distorted pattern of intensity and peak ground acceleration (PGA) above the hypocenter with a substantial elongation of isoseismic contours correlated with the configuration of the isodepth contours of the subducting PHP beneath western Japan. A detailed analysis of the dense Hi-net waveform data from the intermediate-depth PHP event shows that the high-frequency S-wave signals suddenly disappear as the waves propagate the zone away from the Kii Channel to the boundary of Hyogo and Okayama prefectures and large S-to-P conversion occurs before the arrival of S-wave. Such anomalies do not occur for shallow and deep earthquakes occurring outside the PHP. These observations support the recent debate on the complexities of the configuration of the PHP subducting beneath western Japan such as that shown by Shiomi et al. (2008) based on receiver function images and the PHP-split model beneath the Kii channel shown by Ide et al.(2010) based on the analysis of comprehensive geophysical data. In order to explain the observations associated with sudden lateral change in the PHP structure, we conducted finite difference method (FDM) simulations of seismic wave propagation taking the detailed PHP model into account. It is confirmed that high-frequency guided wave energy decouple from waveguide where the shape of the PHP is suddenly deformed, which results in dramatic attenuation of high-frequency signals associating with large S-to-P conversions developed at sharp plate boundary. The present results also support the recently proposed complicated PHP-split model, however, further

  17. Temperature thresholds and degree-day model for Marmara gulosa (Lepidoptera: Gracillariidae).

    PubMed

    O'Neal, M J; Headrick, D H; Montez, Gregory H; Grafton-Cardwell, E E

    2011-08-01

    The developmental thresholds for Marmara gulosa Guillén & Davis (Lepidoptera: Gracillariidae) were investigated in the laboratory by using 17, 21, 25, 29, and 33 degrees C. The lowest mortality occurred in cohorts exposed to 25 and 29 degrees C. Other temperatures caused >10% mortality primarily in egg and first and second instar sap-feeding larvae. Linear regression analysis approximated the lower developmental threshold at 12.2 degrees C. High mortality and slow developmental rate at 33 degrees C indicate the upper developmental threshold is near this temperature. The degree-day (DD) model indicated that a generation requires an accumulation of 322 DD for development from egg to adult emergence. Average daily temperatures in the San Joaquin Valley could produce up to seven generations of M. gulosa per year. Field studies documented two, five, and three overlapping generations of M. gulosa in walnuts (Juglans regia L.; Juglandaceae), pummelos (Citrus maxima (Burm.) Merr.; Rutaceae), and oranges (Citrus sinensis (L.) Osbeck; Rutaceae), for a total of seven observed peelminer generations. Degree-day units between generations averaged 375 DD for larvae infesting walnut twigs; however, availability of green wood probably affected timing of infestations. Degree-day units between larval generations averaged 322 for pummelos and 309 for oranges, confirming the laboratory estimation. First infestation of citrus occurred in June in pummelo fruit and August in orange fruit when fruit neared 60 mm in diameter. Fruit size and degree-day units could be used as management tools to more precisely time insecticide treatments to target the egg stage and prevent rind damage to citrus. Degree-day units also could be used to more precisely time natural enemy releases to target larval instars that are preferred for oviposition.

  18. Seismically induced pressure transients at geothermal reservoirs in the eastern Marmara region

    NASA Astrophysics Data System (ADS)

    Woith, Heiko; Wang, Rongjiang; Caka, Deniz; Irmak, T. Serkan; Tunc, Berna; Luehr, Birger-G.; Baris, Serif

    2014-05-01

    The potential role of fluids in processes related to the triggering of earthquakes and volcanic eruptions is frequently emphasized. Here, we focus on the response of hydrogeological systems to earthquakes, specifically on seismically induced pore-pressure variations in geothermal areas located in the eastern Marmara region. At a 500 m deep artesian geothermal well the pressure is continuously being monitored at a sampling rate of 100 Hz. A seismometer is co-located close to the well-head and the data are recorded by the same digitizer. Hydro-seismograms were recorded in relation to local and distant earthquakes. The ML=5.2 Manyas earthquake which occurred on 20 October 2006 at a distance of 77 km led to a dynamic response of the pore pressure of the order of 4 mbar triggered upon the arrival of the S-wave. Four days later, the ML=5.2 Gemlik earthquake at a distance of 20 km led to a dynamic pore pressure response of the order of 15 mbar triggered upon the arrival of the P-wave. In both cases the peak amplitude of the ground velocity was about 2 mm/s. Weak oscillations of the pore pressure were observed during the passage of surface waves generated by remote earthquakes at distances of up to 9,000 km. Additionally to the dynamic response, a small persistent pressure increase of 1 and 2 mbar had been recorded after both local earthquakes. According to preliminary results, the observed pressure increase is opposite to the static pressure decrease predicted by Okada's model. At the present stage we conclude that the response of the Armutlu geothermal system to earthquakes is likely caused by a dynamic interaction of passing seismic waves (P-, S-, and surface waves) with the fluid reservoir in case a threshold of the ground shaking is exceeded.

  19. Marmara University Medical Students’ Perception on Sexual Violence against Women and Induced Abortion in Turkey

    PubMed Central

    Lüleci, Nimet Emel; Kaya, Eda; Aslan, Ece; Şenkal, Ece Söylem; Çiçek, Zehra Nadide

    2016-01-01

    Background: Historically, sexual assault is a common issue in Turkey. As doctors are one of the steps to help sexually assaulted women, medical students should have basic knowledge of and sensitivity regarding this subject. Another common women’s public health issue is induced abortion. In countries where access to abortion is restricted, there is a tendency towards unhealthy abortion. Aims: The aims of this study are: (1) to determine the attitudes and opinions of Marmara University Medical Faculty students about sexual assault against women and induced abortion and (2) to propose an educational program for medical students about sexual assault and abortion. Study Design: Cross-sectional study. Methods: The questionnaires were self-administered and the data were analyzed using SPSS v.15.0. First, the descriptive statistics were analyzed, followed by Chi-square for contingency tests assessing differences in attitudes toward sexual assault and induced abortion by factors such as gender and educational term. Differences were considered statistically significant at p<0.05. Results: About 89.6% of the participants (n=266) reported that they had never been sexually assaulted and about 11.5% of the women (n=19) had been sexually assaulted. There was no significant relationship between previous sexual assault and gender (p>0.05). Although there was no significant difference regarding the extent of punishment by victim’s status as a virgin, 21.3% (n=63) agreed that punishment should be more severe when the victim was a virgin. About 40.7% (n=120) agreed that the legal period of abortion in Turkey (10 weeks) should be longer. The majority (86.1%, n=255) agreed that legally prohibiting abortions causes an increase in unhealthy abortions. Conclusion: An educational program on these issues should be developed for medical students. PMID:27403386

  20. The Role of Philippine Sea Plate to the Genesis of Quaternary Magmas of Northern Kyushu Island, Japan, Inferred from Along-Arc Geochemical Variations

    NASA Astrophysics Data System (ADS)

    Shibata, T.; Yoshikawa, M.; Itoh, J.; Ujike, O.; Miyoshi, M.; Takemura, K.

    2013-12-01

    geochemical data, including Sr, Nd, and Pb isotope ratios, were restricted to Kuju and Yufu-Tsurumi volcanoes (Kita et al., 2001; Sugimoto et al., 2007), and hence we present new geochemical and Sr-Nd-Pb isotope ratios of lavas from Himeshima and Futagoyama volcanoes and Nd-Pb isotope ratios of Aso volcano. The Sr/Y ratios of the arc lavas decrease from north to south along the volcanic front. Mixing relations in Sr-Nd-Pb isotope space suggest recycling of the subducted slab materials from the Philippine Sea Plate to the arc. The 87Sr/86Sr ratios decrease with increasing Sr/Y and SiO2, which argues against a genetic link of fractional crystallization between adakites and basaltic magmas. The observations further suggest that partial melting of the hot and young Shikoku Basin slab produces the high Sr/Y component visible in the arc magmas in the north, whereas dehydration of the older West Philippine Basin slab produces the low Sr/Y arc magmas in the south. References Hunter, 1998, Chemical Geology, 201: 19-36. Kita et al., 2001, Journal of Volcanology and Geothermal Research, 111, 99-109. Mahony et al., 2011, Geological Society of America Bulletin, 123, 2201-2223. Sugimoto et al., 2007, Journal of Mineralogical and Petrological Sciences, 101: 270-275. Zellmer et al., 2012, Geology, 40: 487-490.

  1. Crustal structure and configuration of the subducting Philippine Sea plate beneath the Pacific coast industrial zone in Japan inferred from receiver function analysis

    NASA Astrophysics Data System (ADS)

    Igarashi, T.; Iidaka, T.; Sakai, S.; Hirata, N.

    2012-12-01

    We apply receiver function (RF) analyses to estimate the crustal structure and configuration of the subducting Philippine Sea (PHS) plate beneath the Pacific coast industrial zone stretching from Tokyo to Fukuoka in Japan. Destructive earthquakes often occurred at the plate interface of the PHS plate, and seismic activities increase after the 2011 Tohoku earthquake (Mw9.0) around the Tokyo metropolitan area. Investigation on the crustal structure is the key to understanding the stress concentration and strain accumulation process, and information on configuration of the subducting plate is important to mitigate future earthquake disasters. In this study, we searched for the best-correlated velocity structure model between an observed receiver function at each station and synthetic ones by using a grid search method. Synthetic RFs were calculated from many assumed one-dimensional velocity structures that consist of four layers with positive velocity steps. Observed receiver functions were stacked without considering back azimuth or epicentral distance. We further constructed the vertical cross-sections of depth-converted RF images transformed the lapse time of time series to depth by using the estimated structure models. Telemetric seismographic network data covered on the Japanese Islands including the Metropolitan Seismic Observation network, which constructed under the Special Project for Earthquake Disaster Mitigation in the Tokyo Metropolitan area and maintained by Special Project for Reducing Vulnerability for Urban Mega Earthquake Disasters, are used. We selected events with magnitudes greater or equal to 5.0 and epicentral distance between 30 and 90 degrees based on USGS catalogues. As a result, we clarify spatial distributions of the crustal S-wave velocities. Estimated average one-dimensional S-wave velocity structure is approximately equal to the JMA2011 structural model although the velocity from the ground surface to 5 km in depth is slow. In particular

  2. Particulate and dissolved primary production along a pronounced hydrographic and trophic gradient (Turkish Straits System-NE Aegean Sea)

    NASA Astrophysics Data System (ADS)

    Lagaria, A.; Psarra, S.; Gogou, A.; Tuğrul, S.; Christaki, U.

    2013-06-01

    The rates of particulate (PPp) and dissolved primary production (PPd) were estimated along a trajectory of variable environmental regimes formed in a narrow shelf area, following the course of Black Sea water masses (BSW) passing through the Turkish Straits System (TSS) into the NE Aegean Sea (BS-AS outflow). Seven stations in total were sampled, covering a transect from the eastern edge of the Marmara Sea basin to the NE Aegean Sea, during two consecutive cruises performed in October 2008 within the framework of the EU SESAME project. Along the BS-AS outflow, depth-integrated over the surface BSW layer PPp decreased considerably from 91 to < 16 mg C m- 2 h- 1 whereas PPd increased from 3 to 10 mg C m- 2 h- 1. As a consequence, the relative importance of PPd over total production (percentage extracellular release, PER) increased from 6% (± 3% sd) in the Marmara Sea to 37% (± 4% sd) in the NE Aegean Sea. Total chlorophyll a concentration gradually decreased and phytoplankton community size-structure was modified, with pico-phytoplankton, that originally represented 35% (± 9% sd) in the Marmara Sea, gradually becoming dominant in the NE Aegean (77% ± 2% sd), substituting large nano- and micro-phytoplankton cells (> 5 μm). This study showed that PER increased along a gradient from mesotrophy to oligotrophy, probably due to nutrient deficiency constraining phytoplankton growth and was closely related to phytoplankton size-structure. In the oligotrophic NE Aegean Sea, phytoplankton exudation was a significant source of dissolved organic carbon for heterotrophic prokaryotes.

  3. Monitoring small land subsidence phenomena in the Marmara see region by new SAR generation satellite ESA Sentinel 1

    NASA Astrophysics Data System (ADS)

    Cantone, Alessio; Riccardi, Paolo; Pasquali, Paolo; Defilippi, Marco; Peternier, Achille

    2015-04-01

    The Marmara see region is a large and dense urbanized area affected by tectonics deformations due to the presence of the underlying North Anatolia Fault. This area is affected by strong seismic phenomena (Izmith and Duzce earthquake), and by landslide and small surface deformation. The new generation ESA SAR satellites Copernicus Sentinel-1 system TOPS (Terrain Observation with Progressive Scans in azimuth) permit a short acquisition repetition cycle, an extreme large coverage, a high spatial resolution to respect the covered area and a small baseline separation. All of those characteristics suggest an intensive exploitation of these data through the usage of the interferometry technology and in particular the stacking interferometry for the small terrain displacement monitoring. The Sentinel-1 mission is made up of a constellation of two satellites (A and B units) each carrying a C-band SAR sensor. The objective of the S-1 mission is to acquire systematically with a 12-day repeat orbit cycle for each satellite with a small orbital baselines, characteristics particularly suited for interferometry application. In the near future, when both satellites will be active, there will be an acquisition every 6 days, covering the whole area. The first TOPSAR interferogram has been successfully produced, and the SARScape® stacking processing chains (SBAS and PSI) have been update to support this new sensor. The SBAS (Small Baseline) technique seems to be the best candidate for this application relatively to the morphology and large extension of Marmara region. Moreover the new incremental SBAS will permit a velocity map (at about 25 meters spatial resolution) estimation at near real time at each Sentinel-1 acquisition. We are collecting imaging over the Marmara since October 2014 within the framework of European FP7 Marsite project. In February-March 2015 we will have enough acquisition to perform the first SBAS TOPSAR monitoring of this area. The SBAS processing chain has

  4. Evaluation of seismic hazard in Marmara region based on the new datasets developed in the EU-MARSITE Project

    NASA Astrophysics Data System (ADS)

    Sesetyan, Karin; Akinci, Aybige; Betül Demircioglu, Mine

    2016-04-01

    Several studies with various degrees of sophistication have been conducted for the probabilistic assessment of seismic hazard in the Marmara Region (e.g. Atakan et al., 2002; Erdik et al., 2004; Kalkan et al., 2008; Gülerce and Ocak, 2013),. The common point of these studies was that they have all addressed the hazard in the region in terms of both time-independent probabilistic (simple Poissonian) and time-dependent probabilistic (renewal) models. This tendency was governed by the following considerations: 1) the region has experienced a considerable number of large magnitude events in the history, which have also shown some periodicity; 2) the existing seismic gap and the post-1999 earthquake stress transfer at the western portion of the 1000km-long NAFZ indicates a high probability of having a M>7 event in the near future close to the city of Istanbul; 3)the seismic history of the region was well documented and studied and there have been, especially in the aftermath of the 1999 Kocaeli and Düzce events, several geological investigations both on-shore and off-shore aiming to obtain a regional fault model as complete as possible, which were reflected in the fault segmentation models of the PSHA studies. Task 5.5. of the MARSITE Project aimed at a reassessment of the probabilistic seismic hazard of the Marmara region in the light of the new datasets compiled in the project. The improvement of the knowledge on the seismotectonic regime of the Marmara region paved the path for the development of alternative source models for the improvement of the existing probabilistic seismic hazard maps. In this connection, the most recent findings and outputs of different work packages of the project, in terms of seismicity, fault segmentation and slip rate data are utilized. A revised fault segementation model and associated Poisson and renewal recurrence models as well as recently emerged global and regional ground motion prediction equations are used to assessed the seismic

  5. Multiple Instance Fuzzy Inference

    DTIC Science & Technology

    2015-12-02

    INFERENCE A novel fuzzy learning framework that employs fuzzy inference to solve the problem of multiple instance learning (MIL) is presented. The...fuzzy learning framework that employs fuzzy inference to solve the problem of multiple instance learning (MIL) is presented. The framework introduces a...or learned from data. In multiple instance problems, the training data is ambiguously labeled. Instances are grouped into bags, labels of bags are

  6. Spatial patterns of biodiversity in the Black Sea: An assessment using benthic polychaetes

    NASA Astrophysics Data System (ADS)

    Surugiu, Victor; Revkov, Nikolai; Todorova, Valentina; Papageorgiou, Nafsika; Valavanis, Vasilis; Arvanitidis, Christos

    2010-06-01

    The current study broadens the biodiversity information available for the Black Sea and neighbouring regions and improves our knowledge about the polychaete biogeographic patterns to be discerned in them. There appears to be a well-defined zoogeocline from the Marmara Sea and Bosphorus Strait to the inner parts of the region (Azov Sea), depicted both as a multivariate pattern and in terms of species (or taxa) numbers. The emergent multivariate pattern complies, to a certain extent, with Jakubova's (1935) views: three main sectors can be defined in the basin: (a) Prebosphoric, (b) the Black Sea and, (c) the Azov Sea, whereas the Bosphorus Strait and Marmara Sea show less faunal affinities with the afore-mentioned sectors. Patterns derived both from the cosmopolitan and Atlanto-Mediterranean species closely follow the one coming from the polychaete species and genera inventories. As a general trend, species numbers decrease along with the decrease in salinity towards the inner parts of the region. The trend is homologous to that seen in the benthic invertebrate inventories of all the major European semi-enclosed regional seas. Salinity and food availability appear to be the dominant abiotic factors correlated, though weakly, with the various patterns deriving from the taxonomic/zoogeographic categories. With the exception of the Anatolia, polychaete inventories from all sectors appear to be random samples of the total inventory of the region, in terms of taxonomic distinctness values. Therefore, these sectoral inventories can be used for future biodiversity/environmental impact assessment studies. A massive invasion of Mediterranean species after the opening of the Black Sea, in the lower Quaternary period, appears to be the likely biogeographic mechanism through which the old Sarmatic fauna was almost completely replaced by species of marine origin.

  7. Inference in `poor` languages

    SciTech Connect

    Petrov, S.

    1996-10-01

    Languages with a solvable implication problem but without complete and consistent systems of inference rules (`poor` languages) are considered. The problem of existence of finite complete and consistent inference rule system for a ``poor`` language is stated independently of the language or rules syntax. Several properties of the problem arc proved. An application of results to the language of join dependencies is given.

  8. Radioactivity measurements in moss (Hypnum cupressiforme) and lichen (Cladonia rangiformis) samples collected from Marmara region of Turkey.

    PubMed

    Belivermiş, Murat; Cotuk, Yavuz

    2010-11-01

    The present study was conducted to compare the (137)Cs, (40)K, (232)Th, and (238)U activity concentrations in epigeic moss (Hypnum cupressiforme) and lichen (Cladonia rangiformis). The activity levels in 37 moss and 38 lichen samples collected from the Marmara region of Turkey were measured using a gamma spectrometer equipped with a high purity germanium (HPGe) detector. The activity concentrations of (137)Cs, (40)K, (232)Th, and (238)U in the moss samples were found to be in the range of 0.36-8.13, 17.1-181.1, 1.51-6.17, and 0.87-6.70 Bq kg(-1) respectively, while these values were below detection limit (BDL)-4.32, 16.6-240.0, 1.32-6.47, and BDL-3.57 Bq kg(-1) respectively in lichen. The average moss/lichen activity ratios of (137)Cs, (40)K, (232)Th, and (238)U were found to be 1.32 +/- 0.57, 2.79 +/- 1.67, 2.11 +/- 0.82, and 2.19 +/- 1.02, respectively. Very low (137)Cs concentrations were observed in moss and lichen samples compared to soil samples collected from the same locations in a previous study. Seasonal variations of the measured radionuclide activities were also examined in the three sampling stations.

  9. Source mechanism of the 2014 Aegean Sea earthquake

    NASA Astrophysics Data System (ADS)

    Nakano, Masaru

    2016-04-01

    Rapid determination of centroid moment tensor (CMT) of earthquakes, namely the source centroid location, focal mechanism, and magnitude is important for early disaster responses and issuing Tsunami warnings. In order to evaluate capability of Turkey seismic network for rapid determinations of CMT, I investigate the source mechanism of the 2014 Aegean Sea earthquake (Mw 6.9). Although this event occur out of Turkey seismic network, I obtained stable CMT solution. The CMT solution of this earthquake represents a strike-slip fault, consistent with the geometry of the North Anatolian Fault (NAF), and the source-time function indicates that this event comprised several distinct subevents. Each subevent is considered to have ruptured a different fault segment. This observation indicates the existence of a mechanical barrier, namely a NAF segment boundary, at the hypocenter. I also determined CMT solutions of background seismicity. CMT solutions of background seismicity beneath the Aegean Sea represent strike-slip or normal faulting along the NAF or its branch faults. The tensional axes of these events are oriented northeast-southwest, indicating a transtensional tectonic regime. Beneath the Sea of Marmara, the CMT solutions represent mostly strike-slip faulting, consistent with the motion of the NAF, but we identified a normal fault event with a tensional axis parallel to the strike of the NAF. This mechanism indicates that a pull-apart basin, marking a segment boundary of the NAF, is developing there. Because ruptures of a fault system and large earthquake magnitudes are strongly controlled by the fault system geometry and fault length, mapping fault segments along NAF can help to improve the accuracy of scenarios developed for future disastrous earthquakes in the Marmara region.

  10. Evolution and fluxes of 137Cs in the Black Sea/Turkish Straits System/North Aegean Sea

    NASA Astrophysics Data System (ADS)

    Delfanti, R.; Özsoy, E.; Kaberi, H.; Schirone, A.; Salvi, S.; Conte, F.; Tsabaris, C.; Papucci, C.

    2014-07-01

    The vertical profiles of 137Cs were determined in the North Aegean, Marmara and Black Seas, to assess inventories and fluxes of the radionuclide in these basins. The inventory of 137Cs in the Western Black Sea integrated from the surface down to 400 m water depth is 3.4 ± 0.1 kBq m- 2, which is surprisingly close to the amount determined in 1988, decay corrected to 2007 (2.9 ± 0.1 kBq m- 2). On the other hand, based on the comparison of profiles roughly 20 years apart, it is estimated that about 1 kBq m- 2 has been transferred from above the halocline to depths below the halocline, emphasizing the effective redistribution of tracers within the same period. We estimate that about 12 TBq y- 1 of 137Cs presently leaves the Black Sea with the upper layer flow through the Bosphorus and only 2 TBq y- 1 is returned with the lower layer inflow of Mediterranean water from the Marmara Sea. Accounting for river fluxes, estimated on the order of 2 TBq y- 1 few years after the Chernobyl accident, and possibly decreased by now, we can thus estimate a net rate of loss of about 8-10 TBq y- 1. Investigating the effective redistribution in the upper water column, the supply by the inflowing Mediterranean water alone does not explain the increase of 137Cs concentration and inventory at intermediate depths in the Western Black Sea. The most important mechanism transferring 137Cs and dissolved contaminants from the surface water to the sub-pycnocline layer appears to be the turbulent entrainment of a larger quantity of Black Sea water into the inflowing plume of Mediterranean water through mixing processes on the southwestern shelf and continental slope following its exit from the Bosphorus. This process produces an extra export of some10 TBq y- 1 of 137Cs from the surface to the sub-pycnocline depths of the Black Sea, a quantity comparable in magnitude to the total export out from the basin. It is the entrainment flux resulting from the mixing, and the further advection and

  11. Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals

    NASA Astrophysics Data System (ADS)

    Dubois-Dauphin, Quentin; Montagna, Paolo; Siani, Giuseppe; Douville, Eric; Wienberg, Claudia; Hebbeln, Dierk; Liu, Zhifei; Kallel, Nejib; Dapoigny, Arnaud; Revel, Marie; Pons-Branchu, Edwige; Taviani, Marco; Colin, Christophe

    2017-01-01

    We present the neodymium isotopic composition (ɛNd) of mixed planktonic foraminifera species from a sediment core collected at 622 m water depth in the Balearic Sea, as well as ɛNd of scleractinian cold-water corals (CWC; Madrepora oculata, Lophelia pertusa) retrieved between 280 and 442 m water depth in the Alboran Sea and at 414 m depth in the southern Sardinian continental margin. The aim is to constrain hydrological variations at intermediate depths in the western Mediterranean Sea during the last 20 kyr. Planktonic (Globigerina bulloides) and benthic (Cibicidoides pachyderma) foraminifera from the Balearic Sea were also analyzed for stable oxygen (δ18O) and carbon (δ13C) isotopes. The foraminiferal and coral ɛNd values from the Balearic and Alboran seas are comparable over the last ˜ 13 kyr, with mean values of -8.94 ± 0.26 (1σ; n = 24) and -8.91 ± 0.18 (1σ; n = 25), respectively. Before 13 ka BP, the foraminiferal ɛNd values are slightly lower (-9.28 ± 0.15) and tend to reflect higher mixing between intermediate and deep waters, which are characterized by more unradiogenic ɛNd values. The slight ɛNd increase after 13 ka BP is associated with a decoupling in the benthic foraminiferal δ13C composition between intermediate and deeper depths, which started at ˜ 16 ka BP. This suggests an earlier stratification of the water masses and a subsequent reduced contribution of unradiogenic ɛNd from deep waters. The CWC from the Sardinia Channel show a much larger scatter of ɛNd values, from -8.66 ± 0.30 to -5.99 ± 0.50, and a lower average (-7.31 ± 0.73; n = 19) compared to the CWC and foraminifera from the Alboran and Balearic seas, indicative of intermediate waters sourced from the Levantine basin. At the time of sapropel S1 deposition (10.2 to 6.4 ka), the ɛNd values of the Sardinian CWC become more unradiogenic (-8.38 ± 0.47; n = 3 at ˜ 8.7 ka BP), suggesting a significant contribution of intermediate waters originated from the western basin

  12. Investigation of Total Crustal Movements Using Terrestrial and GPS Measurements along the Western Part of North Anatolian Fault in the Marmara Region

    NASA Astrophysics Data System (ADS)

    Ozener, H.; Akay, G.

    2007-12-01

    In order to monitor crustal movements along southern branch of North Anatolian Fault Zone (NAFZ), Geodesy Department of Kandilli Observatory and Earthquake Research Institute (KOERI) initiated to establish microgeodetic networks around eastern Marmara Region. General Command of Mapping (GCM)-Istanbul Technical University (ITU) network was constituted of nine pillars, measured five times between 1941 and 2007 applying with respectively trialteration, triangulation and space geodetic methods. In years 2004 and 2007 GPS campaign processing was extended and re-evaluated by adding three new stations from Marmara Region Continuous GPS Observation (MAGNET) network. This study aimed to gather displacements of the GCM-ITU network and analyze the movements of the stations in order to monitor crustral deformation along the Iznik fault. By taking the stations located at the south of the fault as stabilized, the displacements of the remaining stations were evaluated. The movements of stations were found to be ranging between 19 cm to 2 mm according to the accuracy of observation method. The results demonstrated that the stations at both the south and the north of the fault have moved during the 1941-2007 period, and these movements were independent of the movement of the fault itself.

  13. The Bayes Inference Engine

    SciTech Connect

    Hanson, K.M.; Cunningham, G.S.

    1996-04-01

    The authors are developing a computer application, called the Bayes Inference Engine, to provide the means to make inferences about models of physical reality within a Bayesian framework. The construction of complex nonlinear models is achieved by a fully object-oriented design. The models are represented by a data-flow diagram that may be manipulated by the analyst through a graphical programming environment. Maximum a posteriori solutions are achieved using a general, gradient-based optimization algorithm. The application incorporates a new technique of estimating and visualizing the uncertainties in specific aspects of the model.

  14. Inference as Prediction

    ERIC Educational Resources Information Center

    Watson, Jane

    2007-01-01

    Inference, or decision making, is seen in curriculum documents as the final step in a statistical investigation. For a formal statistical enquiry this may be associated with sophisticated tests involving probability distributions. For young students without the mathematical background to perform such tests, it is still possible to draw informal…

  15. Subsidence and conversion of the Dead Sea basin to an inland erosion base level in the early middle Miocene as inferred from geomorphological analysis of its ancient western fluvial outlet

    NASA Astrophysics Data System (ADS)

    Bar, Oded; Zilberman, Ezra

    2016-05-01

    The first major subsidence of the Dead Sea pull-apart basin (DSB) is evidenced by the thick Hufeira Member of the terrestrial Hazeva Formation. The age of the Hufeira Member and the conversion of the DSB to an inland erosion base level are not well constrained. For this purpose we studied the effect of the evolving basin on its ancient fluvial outlet to the Arad-Be'er Sheva Valley (ABSV), which served as a Miocene corridor between the embryonic DSB region in the east and the Mediterranean Sea in the west. We mapped and analyzed the morphostratigraphy of four series of rock-cut erosion surfaces (from top to bottom: the Barir, Kuseifa, Ar'ara, and Shemen surfaces). They are manifested in the east as fluvial erosion surfaces, capped by conglomerates, passing laterally westward to marine wave-cut surfaces, capped by a shallow marine limestone of the early middle Miocene Ziqlag Formation. The age of these surfaces is constrained to the early middle Miocene (Langhian) based on morphostratigraphy correlation with the Ziqlag Formation. Paleogeographic reconstruction of the two higher and older surfaces reveals transverse valleys, which drained the DSB region and crossed the present route of the regional water divide. These transverse valleys were presumably the western outlets to the Mediterranean Sea of the newly subsiding basin. Precambrian components in the assemblage of the clasts that cover the Kuseifa surface were not found in the Hufeira Member and thus reflect an ongoing post-Hufeira exumation of the DSB drainage basin. Hence, this early middle Miocene surface postdates the Hufeira Member, assigning an age of late early Miocene to the first major subsidence of the DSB. The two lower and younger surfaces represent local drainage systems confined to the ABSV. This transition from regional to local drainage system marks the establishment of the present regional water divide and the conversion of the DSB to an inland erosion base level during the early middle Miocene.

  16. Effects of Isolation by Continental Islands in the Seto Inland Sea, Japan, on Genetic Diversity of the Large Japanese Field Mouse, Apodemus speciosus (Rodentia: Muridae), Inferred from the Mitochondrial Dloop Region.

    PubMed

    Sato, Jun J; Tasaka, Yurina; Tasaka, Ryoya; Gunji, Kentaro; Yamamoto, Yuya; Takada, Yasushi; Uematsu, Yasushi; Sakai, Eiichi; Tateishi, Takashi; Yamaguchi, Yasunori

    2017-04-01

    To study the effects of post-glacial isolation by islands on population genetic diversity and differentiation of the large Japanese field mouse, Apodemus speciosus, we examined partial nucleotide sequences of the mitochondrial Dloop region (ca. 300 bp) in 231 individuals collected from islands in the Seto Inland Sea and adjacent regions on Honshu and Shikoku Islands in the western part of the Japanese archipelago. Molecular phylogenetic and network analyses showed that haplotypes in each island tended to form monophyletic groups, while those in Honshu and Shikoku (the major Japanese islands) showed scattered relationships and were connected with island haplotypes. These observations suggest that a set of Honshu and Shikoku haplotypes became the ancestral lineages of the island population. No gene flow was detected among island populations, indicating that independent evolution occurred on each island, without the influence of human activities, since the establishment of the islands in the Holocene. Population genetic diversities on each island were lower than those on Honshu and Shikoku. Comparison between genetic diversity and island area size showed positive correlations and supported the suggestion that genetic drift is a major factor that shaped the current haplotype constitution of the islands in the Seto Inland Sea.

  17. Teaching of the subject "density difference caused by salinity", one of the reasons that plays role in the occurrence of currents in straits, seas and oceans by the use of a teaching material

    NASA Astrophysics Data System (ADS)

    Gumussoy, Verim

    2015-04-01

    Large masses of moving water in seas and oceans are called currents. Root causes of currents are steady winds that occur due to the global atmospheric system and the density differences caused by different heat and salinity levels of water masses. Different feeding and evaporation characteristics of seas and oceans result in salinity and density levels. As a result, subsurface currents occur in straits where seas with different salinity and density levels meet and in the nearby seas. The Bosporus in Istanbul where I live and the school I am working at is has these subsurface currents. In the Black Sea where the rivers the Danube, Dnieper, Don, Yesilirmak, Kizilirmak and Sakarya flow into and the evaporation level is less due to the latitude effect, salinity level is less compared to Marmara and Aegean Seas. As Marmara Sea has higher salt amount than Black Sea, there is a great density difference between these two seas. Marmara Sea has a higher concentration of salt and therefore a higher density than Black Sea. And this leads to occurrence of subsurface currents in the Bosporus. I get my students to carry out a small demonstration to help them understand the occurrence of ocean currents and currents in the seas and the Bosporus by the use of a material. We need very simple materials to carry out this demonstration. These are an aquarium, a bowl, water, salt, dye and a mixer. The demonstration is carried out as follows: we put water, salt and dye in the bowl and mix it well. The salt will increase the density of the water and the dye will help distinguish the salty water. Then we put tap water half way to the aquarium and pour the mixture in the bowl to the aquarium slowly. As a result, the colored salty water sinks down due to its higher density, setting an example of a subsurface current. Natural events occur in very long periods by great dynamic systems, making understanding of them difficult. It is important to use different kinds of materials that address to

  18. Optical Inference Machines

    DTIC Science & Technology

    1988-06-27

    de olf nessse end Id e ;-tl Sb ieeI smleo) ,Optical Artificial Intellegence ; Optical inference engines; Optical logic; Optical informationprocessing...common. They arise in areas such as expert systems and other artificial intelligence systems. In recent years, the computer science language PROLOG has...cal processors should in principle be well suited for : I artificial intelligence applications. In recent years, symbolic logic processing. , the

  19. Active inference and learning.

    PubMed

    Friston, Karl; FitzGerald, Thomas; Rigoli, Francesco; Schwartenbeck, Philipp; O'Doherty, John; Pezzulo, Giovanni

    2016-09-01

    This paper offers an active inference account of choice behaviour and learning. It focuses on the distinction between goal-directed and habitual behaviour and how they contextualise each other. We show that habits emerge naturally (and autodidactically) from sequential policy optimisation when agents are equipped with state-action policies. In active inference, behaviour has explorative (epistemic) and exploitative (pragmatic) aspects that are sensitive to ambiguity and risk respectively, where epistemic (ambiguity-resolving) behaviour enables pragmatic (reward-seeking) behaviour and the subsequent emergence of habits. Although goal-directed and habitual policies are usually associated with model-based and model-free schemes, we find the more important distinction is between belief-free and belief-based schemes. The underlying (variational) belief updating provides a comprehensive (if metaphorical) process theory for several phenomena, including the transfer of dopamine responses, reversal learning, habit formation and devaluation. Finally, we show that active inference reduces to a classical (Bellman) scheme, in the absence of ambiguity.

  20. Multimodel inference and adaptive management

    USGS Publications Warehouse

    Rehme, S.E.; Powell, L.A.; Allen, C.R.

    2011-01-01

    Ecology is an inherently complex science coping with correlated variables, nonlinear interactions and multiple scales of pattern and process, making it difficult for experiments to result in clear, strong inference. Natural resource managers, policy makers, and stakeholders rely on science to provide timely and accurate management recommendations. However, the time necessary to untangle the complexities of interactions within ecosystems is often far greater than the time available to make management decisions. One method of coping with this problem is multimodel inference. Multimodel inference assesses uncertainty by calculating likelihoods among multiple competing hypotheses, but multimodel inference results are often equivocal. Despite this, there may be pressure for ecologists to provide management recommendations regardless of the strength of their study’s inference. We reviewed papers in the Journal of Wildlife Management (JWM) and the journal Conservation Biology (CB) to quantify the prevalence of multimodel inference approaches, the resulting inference (weak versus strong), and how authors dealt with the uncertainty. Thirty-eight percent and 14%, respectively, of articles in the JWM and CB used multimodel inference approaches. Strong inference was rarely observed, with only 7% of JWM and 20% of CB articles resulting in strong inference. We found the majority of weak inference papers in both journals (59%) gave specific management recommendations. Model selection uncertainty was ignored in most recommendations for management. We suggest that adaptive management is an ideal method to resolve uncertainty when research results in weak inference.

  1. Ecosystem Structure Changes in the Turkish Seas as a Response to Overfishing

    NASA Astrophysics Data System (ADS)

    Gazihan Akoglu, Ayse; Salihoglu, Baris; Akoglu, Ekin; Kideys, Ahmet E.

    2013-04-01

    Human population in Turkey has grown more than five-fold since its establishment in 1923 and more than 73 million people are currently living in the country. Turkey is surrounded by partially connected seas (the Black Sea, the Sea of Marmara, the Aegean Sea and the Mediterranean Sea) each of which has significantly different productivity levels and ecosystem characteristics. Increasing human population with its growing socio-economic needs has generated an intensive fishing pressure on the fish stocks in its exclusive economic zone. Fishing grounds in the surrounding seas were exploited with different fishing intensities depending upon their productivity level and catch rates. Hence, the responses of these different ecosystems to overfishing have been realized differently. In this study, changes of the ecosystem structures in the Turkish Seas were comparatively investigated by ecosystem indices such as Marine Trophic Index (MTI), Fishing in Balance (FiB) and Primary Production Required (PPR) to assess the degree of sustainability of the fish stocks for future generations.

  2. Application of time-independent and time-dependent occurrence models on the seismic hazard estimations in the Marmara region, Turkey

    NASA Astrophysics Data System (ADS)

    Murru, M.; Akinci, A.; Console, R.; Falcone, G.; Pucci, S.

    2014-12-01

    We show the effect of time-independent and time-dependent occurrence models on the seismic hazard estimations. The time-dependence is introduced by 1) the Brownian Passage Time (BPT) probability model that is based on a simple physical model of the earthquake cycle, and 2) the fusion of the BPT renewal model with a physical model that considers the earthquake probability perturbation for interacting faults by static Coulomb stress changes We treat the uncertainties in the fault parameters (e.g. slip rate, characteristic magnitude and aperiodicity) of the statistical distribution associated to each examined fault source by a Monte Carlo technique. For a comparison among the results obtained from three different models, we give the probabilities of occurrence of earthquakes Mw > 6.5 for individual fault sources in the Marmara region, over the future 5-10-30 and 50 years, starting on January 1, 2013, considering the 10th, 50th and 90th percentiles of the Monte Carlo distribution. In order to evaluate the impact of the earthquake probability models to ground motion hazard we attempt to calculate the fault-based probabilistic seismic hazard maps (PSHA) of mean Peak Ground Acceleration (PGA) having 10% probability of exceedance in 50 years on rock site condition. We adopted only one Ground Motion Prediction Equation (GMPE) for the active shallow crustal region for assessing the ground shaking hazard in the Marmara region. We observed that the impact of the different occurrence models on the seismic hazard estimate of selected sites is quite high: the hazard may increase by more than 70% or decrease by as much as 70%, depending on the applied model in the selected sites. This difference mostly depends on the time elapsed after the latest major earthquake on a specific fault. We demonstrate that the estimated average recurrence time and the associated magnitude, together with the elapsed time, are crucial parameters in the earthquake probability calculations.

  3. The changes of T-PAH levels and health status of mussels in Izmit bay (Turkey) after Marmara earthquake and subsequent refinery fire.

    PubMed

    Okay, O S; Tolun, L; Telli-Karakoç, F; Tüfekçi, V; Tüfekçi, H; Olgun, A; Morkoç, E

    2003-03-01

    As is well known, a powerful earthquake along the North Anatolian Fault struck the eastern part of the Marmara region on August 17, 1999. Izmit Bay, which is known as one of the most polluted sites of Turkey, was also affected by the quake and the subsequent refinery fire. The measurements performed just before and after the earthquake showed that T-PAH levels increased significantly after the event [Okay OS, Tolun L, Telli-Karakoç F, Tüfekçi V, Tüfekçi H, Morkoç E. Izmit Bay (Turkey) ecosystem after Marmara earthquake and subsequent refinery fire: the long-term data. Marine Pollution Bulletin 2001;42:361-9]. In the framework of ecotoxicological studies, the Bay ecosystem was continuously monitored for T-PAH levels in seawater, sediments and mussels (Mytilus galloprovincialis) to find out whether change occurred during the 2-year period following the earthquake. For that purpose, after the earthquake, the samples were collected six times between the period of September 1999 and March 2001 at coastal stations of the Bay situated away from the mouth of main discharges. The responses of the mussels were also measured by means of the lysosomal stability of the blood cells and feeding rate biomarker techniques at two different sites of the bay. Although the T-PAH levels in all matrices generally showed a decreasing trend, they were found to be still high especially at stations near the refinery. Both biomarker results showed that the health status of the mussels is very poor in the Bay ecosystem, based on the results obtained from the two sites monitored.

  4. A bump on the upper surface of the Philippine Sea plate beneath the Boso Peninsula, Japan inferred from seismic reflection surveys: A possible asperity of the 1703 Genroku earthquake

    NASA Astrophysics Data System (ADS)

    Tsumura, Noriko; Komada, Nozomi; Sano, Junpei; Kikuchi, Shinsuke; Yamamoto, Shuji; Ito, Tanio; Sato, Toshinori; Miyauchi, Takahiro; Kawamura, Tomonori; Shishikura, Masanobu; Abe, Shintaro; Sato, Hiroshi; Kawanaka, Taku; Suda, Shigeyuki; Higashinaka, Motonori; Ikawa, Takeshi

    2009-07-01

    To reveal a subsurface structure beneath the southern part of the Boso Peninsula, Japan, where the Philippine Sea plate is subducting and great interplate earthquakes associated with the subduction occur repeatedly, we conducted a new seismic reflection survey from March to April 2005 (Boso05). We also reanalyzed old multi-channel seismic (MCS) survey data that had been collected off the Boso Peninsula in 1978 (SK78). We found clear strong reflectors beneath the southern coast of the Boso Peninsula. Since common mid points (CMPs) were distributed widely beneath the study area owing to the design of the receiver and shot lines of Boso05, we selected appropriate directions of stacking lines to get the best image of the dipping reflectors by optimum azimuth search (OAS) processing. We carefully checked the seismic profiles at the intersections of the survey lines to confirm the NNE-dipping configuration of the strong reflectors. These strong reflectors were interpreted as the upper surface of the subducting PHS plate from their locations and the estimated velocities beneath the reflectors. Furthermore, these reflectors revealed a topographic high (bump) beneath the southern coast of the Boso Peninsula where the source fault of the Genroku earthquake of 1703 is thought to be located.

  5. [Genetic Differentiation of Sockeye Salmon Oncorhynchus nerka from Kamchatka River Basin and the Lake-River Systems of the West Coast of the Bering Sea as Inferred from Data on Single Nucleotide Polymorphism].

    PubMed

    Khrustaleva, A M; Klovach, N V; Vedischeva, E V; Seeb, J E

    2015-10-01

    The variability of 45 single nucleotide polymorphism loci (SNP) was studied in sockeye salmon from the Kamchatka River basin and four lake-river systems of the west coast of the Bering Sea. Based on the genetic differentiation estimates for the largest sockeye salmon populations of Eastern Kamchatka and Chukotka, the examined samples were combined into two regional groups represented by the population of the Kamchatka River drainage, which included numerous local subpopulations and seasonal races, and the northern population grouping from the rivers of Olutorsko-Navarinsky raion, wherein the sockeye salmon from Maynypilginskaya Lake-River system was relatively isolated. Considerable divergence was observed between the island (Sarannoe Lake, Bering Island) and continental populations. Genetic heterogeneity was revealed and groups of early- and late-maturing individuals were isolated in the sample of late-run sockeye salmon from Kamchatka River. In Apuka River, subdivision of the spawning run into two genetically distinct spatial and temporal groupings was also observed. The results suggest that the differentiation of sockeye salmon samples by single nucleotide substitution frequencies was largely due to differences in the direction and strength of local selection at some loci in the population complexes and intrapopulation groupings from the examined river basins of Eastern Kamchatka, Chukotka, and Commander Islands.

  6. Visual Inference Programming

    NASA Technical Reports Server (NTRS)

    Wheeler, Kevin; Timucin, Dogan; Rabbette, Maura; Curry, Charles; Allan, Mark; Lvov, Nikolay; Clanton, Sam; Pilewskie, Peter

    2002-01-01

    The goal of visual inference programming is to develop a software framework data analysis and to provide machine learning algorithms for inter-active data exploration and visualization. The topics include: 1) Intelligent Data Understanding (IDU) framework; 2) Challenge problems; 3) What's new here; 4) Framework features; 5) Wiring diagram; 6) Generated script; 7) Results of script; 8) Initial algorithms; 9) Independent Component Analysis for instrument diagnosis; 10) Output sensory mapping virtual joystick; 11) Output sensory mapping typing; 12) Closed-loop feedback mu-rhythm control; 13) Closed-loop training; 14) Data sources; and 15) Algorithms. This paper is in viewgraph form.

  7. Advancements in near real time mapping of earthquake and rainfall induced landslides in the Avcilar Peninsula, Marmara Region

    NASA Astrophysics Data System (ADS)

    Coccia, Stella

    2014-05-01

    Stella COCCIA (1), Fiona THEOLEYRE (1), Pascal BIGARRE(1) , Semih ERGINTAV(2), Oguz OZEL(3) and Serdar ÖZALAYBEY(4) (1) National Institute of Industrial Environment and Risks (INERIS) Nancy, France, (2) Kandilli Observatory and Earthquake Research Institute (KOERI), Istanbul, Turkey, (3) Istanbul University (IU), Istanbul, Turkey, (4) TUBITAK MAM, Istanbul, Turkey The European Project MARsite (http://marsite.eu/), started in 2012 and leaded by the KOERI, aims to improve seismic risk evaluation and preparedness to face the next dreadful large event expected for the next three decades. MARsite is thus expected to move a "step forward" the most advanced monitoring technologies, and offering promising open databases to the worldwide scientific community in the frame of other European environmental large-scale infrastructures, such as EPOS (http://www.epos-eu.org/ ). Among the 11 work packages (WP), the main aim of the WP6 is to study seismically-induced landslide hazard, by using and improving observing and monitoring systems in geological, hydrogeotechnical and seismic onshore and offshore areas. One of the WP6 specific study area is the Avcilar Peninsula, situated between Kucukcekmece and Buyukcekmece Lakes in the north-west of the region of Marmara. There, more than 400 landslides are located. According to geological and geotechnical investigations and studies, soil movements of this area are related to underground water and pore pressure changes, seismic forces arising after earthquakes and decreasing sliding strength in fissured and heavily consolidated clays. The WP6 includes various tasks and one of these works on a methodology to develop a dynamic system to create combined earthquake and rainfall induced landslides hazard maps at near real time and automatically. This innovative system could be used to improve the prevention strategy as well as in disaster management and relief operations. Base on literature review a dynamic GIS platform is used to combine

  8. Circular inferences in schizophrenia.

    PubMed

    Jardri, Renaud; Denève, Sophie

    2013-11-01

    A considerable number of recent experimental and computational studies suggest that subtle impairments of excitatory to inhibitory balance or regulation are involved in many neurological and psychiatric conditions. The current paper aims to relate, specifically and quantitatively, excitatory to inhibitory imbalance with psychotic symptoms in schizophrenia. Considering that the brain constructs hierarchical causal models of the external world, we show that the failure to maintain the excitatory to inhibitory balance results in hallucinations as well as in the formation and subsequent consolidation of delusional beliefs. Indeed, the consequence of excitatory to inhibitory imbalance in a hierarchical neural network is equated to a pathological form of causal inference called 'circular belief propagation'. In circular belief propagation, bottom-up sensory information and top-down predictions are reverberated, i.e. prior beliefs are misinterpreted as sensory observations and vice versa. As a result, these predictions are counted multiple times. Circular inference explains the emergence of erroneous percepts, the patient's overconfidence when facing probabilistic choices, the learning of 'unshakable' causal relationships between unrelated events and a paradoxical immunity to perceptual illusions, which are all known to be associated with schizophrenia.

  9. Inferring Horizontal Gene Transfer

    PubMed Central

    Lassalle, Florent; Dessimoz, Christophe

    2015-01-01

    Horizontal or Lateral Gene Transfer (HGT or LGT) is the transmission of portions of genomic DNA between organisms through a process decoupled from vertical inheritance. In the presence of HGT events, different fragments of the genome are the result of different evolutionary histories. This can therefore complicate the investigations of evolutionary relatedness of lineages and species. Also, as HGT can bring into genomes radically different genotypes from distant lineages, or even new genes bearing new functions, it is a major source of phenotypic innovation and a mechanism of niche adaptation. For example, of particular relevance to human health is the lateral transfer of antibiotic resistance and pathogenicity determinants, leading to the emergence of pathogenic lineages [1]. Computational identification of HGT events relies upon the investigation of sequence composition or evolutionary history of genes. Sequence composition-based ("parametric") methods search for deviations from the genomic average, whereas evolutionary history-based ("phylogenetic") approaches identify genes whose evolutionary history significantly differs from that of the host species. The evaluation and benchmarking of HGT inference methods typically rely upon simulated genomes, for which the true history is known. On real data, different methods tend to infer different HGT events, and as a result it can be difficult to ascertain all but simple and clear-cut HGT events. PMID:26020646

  10. Moment inference from tomograms

    USGS Publications Warehouse

    Day-Lewis, F. D.; Chen, Y.; Singha, K.

    2007-01-01

    Time-lapse geophysical tomography can provide valuable qualitative insights into hydrologic transport phenomena associated with aquifer dynamics, tracer experiments, and engineered remediation. Increasingly, tomograms are used to infer the spatial and/or temporal moments of solute plumes; these moments provide quantitative information about transport processes (e.g., advection, dispersion, and rate-limited mass transfer) and controlling parameters (e.g., permeability, dispersivity, and rate coefficients). The reliability of moments calculated from tomograms is, however, poorly understood because classic approaches to image appraisal (e.g., the model resolution matrix) are not directly applicable to moment inference. Here, we present a semi-analytical approach to construct a moment resolution matrix based on (1) the classic model resolution matrix and (2) image reconstruction from orthogonal moments. Numerical results for radar and electrical-resistivity imaging of solute plumes demonstrate that moment values calculated from tomograms depend strongly on plume location within the tomogram, survey geometry, regularization criteria, and measurement error. Copyright 2007 by the American Geophysical Union.

  11. Sea water quality assessment of Prince Islands' beaches in Istanbul.

    PubMed

    Ilter Turkdogan Aydinol, F; Kanat, Gurdal; Bayhan, Hurrem

    2012-01-01

    In this study, seawater samples were subjected to microbiological and physicochemical analysis (water temperature, pH, Secchi disc depth and ammonia) in the Prince Islands which are located in Marmara Sea, being one of the most popular swimming areas in Istanbul. The monitoring program of the study has been carried out in the summer for 6 weeks at eight stations around the Prince Islands. Measured total coliform values were between 5 ± 2 and 26 ± 55 and faecal coliform values were between 4 ± 2 and 24 ± 50 in the monitoring stations. A statistical study has been conducted to find the relationship between total and faecal coliform concentrations, and t tests were applied. There was no significant difference in each location of the Islands, except one location. The results were evaluated by comparing with national and EU bathing water standards. Results of the study show that deep sea discharges and sea currents contribute dilution of coliform concentration in a positive way, and locations near coastal zones of the islands have acceptable values which are required by the regulations.

  12. BIE: Bayesian Inference Engine

    NASA Astrophysics Data System (ADS)

    Weinberg, Martin D.

    2013-12-01

    The Bayesian Inference Engine (BIE) is an object-oriented library of tools written in C++ designed explicitly to enable Bayesian update and model comparison for astronomical problems. To facilitate "what if" exploration, BIE provides a command line interface (written with Bison and Flex) to run input scripts. The output of the code is a simulation of the Bayesian posterior distribution from which summary statistics e.g. by taking moments, or determine confidence intervals and so forth, can be determined. All of these quantities are fundamentally integrals and the Markov Chain approach produces variates heta distributed according to P( heta|D) so moments are trivially obtained by summing of the ensemble of variates.

  13. Bayesian inference in geomagnetism

    NASA Technical Reports Server (NTRS)

    Backus, George E.

    1988-01-01

    The inverse problem in empirical geomagnetic modeling is investigated, with critical examination of recently published studies. Particular attention is given to the use of Bayesian inference (BI) to select the damping parameter lambda in the uniqueness portion of the inverse problem. The mathematical bases of BI and stochastic inversion are explored, with consideration of bound-softening problems and resolution in linear Gaussian BI. The problem of estimating the radial magnetic field B(r) at the earth core-mantle boundary from surface and satellite measurements is then analyzed in detail, with specific attention to the selection of lambda in the studies of Gubbins (1983) and Gubbins and Bloxham (1985). It is argued that the selection method is inappropriate and leads to lambda values much larger than those that would result if a reasonable bound on the heat flow at the CMB were assumed.

  14. Bayes factors and multimodel inference

    USGS Publications Warehouse

    Link, W.A.; Barker, R.J.; Thomson, David L.; Cooch, Evan G.; Conroy, Michael J.

    2009-01-01

    Multimodel inference has two main themes: model selection, and model averaging. Model averaging is a means of making inference conditional on a model set, rather than on a selected model, allowing formal recognition of the uncertainty associated with model choice. The Bayesian paradigm provides a natural framework for model averaging, and provides a context for evaluation of the commonly used AIC weights. We review Bayesian multimodel inference, noting the importance of Bayes factors. Noting the sensitivity of Bayes factors to the choice of priors on parameters, we define and propose nonpreferential priors as offering a reasonable standard for objective multimodel inference.

  15. Improving Inferences from Multiple Methods.

    ERIC Educational Resources Information Center

    Shotland, R. Lance; Mark, Melvin M.

    1987-01-01

    Multiple evaluation methods (MEMs) can cause an inferential challenge, although there are strategies to strengthen inferences. Practical and theoretical issues involved in the use by social scientists of MEMs, three potential problems in drawing inferences from MEMs, and short- and long-term strategies for alleviating these problems are outlined.…

  16. Causal Inference and Developmental Psychology

    ERIC Educational Resources Information Center

    Foster, E. Michael

    2010-01-01

    Causal inference is of central importance to developmental psychology. Many key questions in the field revolve around improving the lives of children and their families. These include identifying risk factors that if manipulated in some way would foster child development. Such a task inherently involves causal inference: One wants to know whether…

  17. Causal Inference in Retrospective Studies.

    ERIC Educational Resources Information Center

    Holland, Paul W.; Rubin, Donald B.

    1988-01-01

    The problem of drawing causal inferences from retrospective case-controlled studies is considered. A model for causal inference in prospective studies is applied to retrospective studies. Limitations of case-controlled studies are formulated concerning relevant parameters that can be estimated in such studies. A coffee-drinking/myocardial…

  18. Social Inference Through Technology

    NASA Astrophysics Data System (ADS)

    Oulasvirta, Antti

    Awareness cues are computer-mediated, real-time indicators of people’s undertakings, whereabouts, and intentions. Already in the mid-1970 s, UNIX users could use commands such as “finger” and “talk” to find out who was online and to chat. The small icons in instant messaging (IM) applications that indicate coconversants’ presence in the discussion space are the successors of “finger” output. Similar indicators can be found in online communities, media-sharing services, Internet relay chat (IRC), and location-based messaging applications. But presence and availability indicators are only the tip of the iceberg. Technological progress has enabled richer, more accurate, and more intimate indicators. For example, there are mobile services that allow friends to query and follow each other’s locations. Remote monitoring systems developed for health care allow relatives and doctors to assess the wellbeing of homebound patients (see, e.g., Tang and Venables 2000). But users also utilize cues that have not been deliberately designed for this purpose. For example, online gamers pay attention to other characters’ behavior to infer what the other players are like “in real life.” There is a common denominator underlying these examples: shared activities rely on the technology’s representation of the remote person. The other human being is not physically present but present only through a narrow technological channel.

  19. Seasonal constraints on inferred planetary heat content

    NASA Astrophysics Data System (ADS)

    McKinnon, Karen A.; Huybers, Peter

    2016-10-01

    Planetary heating can be quantified using top of the atmosphere energy fluxes or through monitoring the heat content of the Earth system. It has been difficult, however, to compare the two methods with each other because of biases in satellite measurements and incomplete spatial coverage of ocean observations. Here we focus on the the seasonal cycle whose amplitude is large relative to satellite biases and observational errors. The seasonal budget can be closed through inferring contributions from high-latitude oceans and marginal seas using the covariance structure of National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM1). In contrast, if these regions are approximated as the average across well-observed regions, the amplitude of the seasonal cycle is overestimated relative to satellite constraints. Analysis of the same CESM1 simulation indicates that complete measurement of the upper ocean would increase the magnitude and precision of interannual trend estimates in ocean heating more than fully measuring the deep ocean.

  20. An optical model for the microwave properties of sea ice

    NASA Technical Reports Server (NTRS)

    Gloersen, P.; Larabee, J. K.

    1981-01-01

    The complex refractive index of sea ice is modeled and used to predict the microwave signatures of various sea ice types. Results are shown to correspond well with the observed values of the complex index inferred from dielectic constant and dielectric loss measurements performed in the field, and with observed microwave signatures of sea ice. The success of this modeling procedure vis a vis modeling of the dielectric properties of sea ice constituents used earlier by several others is explained. Multiple layer radiative transfer calculations are used to predict the microwave properties of first-year sea ice with and without snow, and multiyear sea ice.

  1. The use of remote sensing and geographic information systems for the evaluation of river basins: a case study for Turkey, Marmara River Basin and Istanbul.

    PubMed

    Ulugtekin, Necla; Balcik, Filiz Bektas; Dogru, Ahmet O; Goksel, Cigdem; Alaton, Idil Arslan; Orhon, Derin

    2009-03-01

    The aim of this study was to determine sensitive river basins and specific areas that urgently need planning activities for sustainable resource and environmental management. In this context, a combination of remote sensing (RS) and geographic information systems (GIS) were employed. For that purpose, a comprehensive overview of the current situation of Turkish river basins in terms of existing spatial data was provided and all tabular data gathered from the national authorities on regional basis was assessed in combination with the geometric data of Turkish river basins in a GIS environment. Considering the GIS studies that covered all 26 Turkish basins, the Marmara River Basin was selected as the model sensitive region and was studied in more detail by using 2000 dated Landsat 7 ETM mosaic satellite image. Results of this comprehensive study indicated that Istanbul, which is located in the basin under study and the largest metropolitan of Turkey, was determined as the most populated and urbanized area of the region. Istanbul was further examined to determine the expansion of urban areas over a time period of 16 years using Landsat images dated 1984, 1992 and 2000. Finally, interpretations were done by combining the demographic and statistical data on urban wastewater treatment plants to present the prevailing situation of the water treatment facilities in Istanbul. Our study not only delineated the importance of applying environmental policies correctly for the efficient installation and operation of urban wastewater treatment plants in Istanbul but also demonstrated that effective urban wastewater management is a nationwide problem in Turkey.

  2. Salish Sea

    EPA Pesticide Factsheets

    The Health of the Salish Sea Report is a collaboration between EPA and Environment Canada to examine the health of the Salish Sea ecosystem in Washington and British Columbia, encompassing the Puget Sound and Georgia Basin.

  3. Bayesian Inference of Galaxy Morphology

    NASA Astrophysics Data System (ADS)

    Yoon, Ilsang; Weinberg, M.; Katz, N.

    2011-01-01

    Reliable inference on galaxy morphology from quantitative analysis of ensemble galaxy images is challenging but essential ingredient in studying galaxy formation and evolution, utilizing current and forthcoming large scale surveys. To put galaxy image decomposition problem in broader context of statistical inference problem and derive a rigorous statistical confidence levels of the inference, I developed a novel galaxy image decomposition tool, GALPHAT (GALaxy PHotometric ATtributes) that exploits recent developments in Bayesian computation to provide full posterior probability distributions and reliable confidence intervals for all parameters. I will highlight the significant improvements in galaxy image decomposition using GALPHAT, over the conventional model fitting algorithms and introduce the GALPHAT potential to infer the statistical distribution of galaxy morphological structures, using ensemble posteriors of galaxy morphological parameters from the entire galaxy population that one studies.

  4. Statistical Inference in Graphical Models

    DTIC Science & Technology

    2008-06-17

    Probabilistic Network Library ( PNL ). While not fully mature, PNL does provide the most commonly-used algorithms for inference and learning with the efficiency...of C++, and also offers interfaces for calling the library from MATLAB and R 1361. Notably, both BNT and PNL provide learning and inference algorithms...mature and has been used for research purposes for several years, it is written in MATLAB and thus is not suitable to be used in real-time settings. PNL

  5. Statistical Inference: The Big Picture.

    PubMed

    Kass, Robert E

    2011-02-01

    Statistics has moved beyond the frequentist-Bayesian controversies of the past. Where does this leave our ability to interpret results? I suggest that a philosophy compatible with statistical practice, labelled here statistical pragmatism, serves as a foundation for inference. Statistical pragmatism is inclusive and emphasizes the assumptions that connect statistical models with observed data. I argue that introductory courses often mis-characterize the process of statistical inference and I propose an alternative "big picture" depiction.

  6. Bayesian Inference: with ecological applications

    USGS Publications Warehouse

    Link, William A.; Barker, Richard J.

    2010-01-01

    This text provides a mathematically rigorous yet accessible and engaging introduction to Bayesian inference with relevant examples that will be of interest to biologists working in the fields of ecology, wildlife management and environmental studies as well as students in advanced undergraduate statistics.. This text opens the door to Bayesian inference, taking advantage of modern computational efficiencies and easily accessible software to evaluate complex hierarchical models.

  7. Inferring the Why in Images

    DTIC Science & Technology

    2014-01-01

    images. To our knowledge, this challenging problem has not yet been extensively explored in computer vision. We present a novel learning based...automatically infers why people are performing actions in images by learning from visual data and written language. ∗denotes equal contribution 1 Report...explored in computer vision. We present a novel learning based framework that uses high-level visual recognition to infer why people are performing

  8. The Cosmonaut Sea Wedge

    USGS Publications Warehouse

    Solli, K.; Kuvaas, B.; Kristoffersen, Y.; Leitchenkov, G.; Guseva, J.; Gandyukhin, V.

    2007-01-01

    A set of multi-channel seismic profiles (~15000 km) acquired by Russia, Norway and Australia has been used to investigate the depositional evolution of the Cosmonaut Sea margin of East Antarctica. We recognize a regional sediment wedge below the upper part of the continental rise. The wedge, herein termed the Cosmonaut Sea Wedge, is positioned stratigraphically underneath the inferred glaciomarine section and extends for at least 1200 km along the continental margin and from 80 to about 250 km seaward or to the north. Lateral variations in the growth pattern of the wedge indicate several overlapping depocentres, which at their distal northern end are flanked by elongated mounded drifts and contourite sheets. The internal stratification of the mounded drift deposits suggests that westward flowing bottom currents reworked the marginal deposits. The action of these currents together with sea-level changes is considered to have controlled the growth of the wedge. We interpret the Cosmonaut Sea Wedge as a composite feature comprising several bottom current reworked fan systems.

  9. Red Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  The Red Sea     View Larger Image ... 2000. Located between the East African coast and the Saudi Arabian peninsula, the Red Sea got its name because the blooms of a type of ... 2000 - The Red Sea between the East Africa coast and Saudi Arabian peninsula. project:  MISR category:  ...

  10. Bering Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The skies of the Bering Sea were relatively clear again in this SeaWiFS image showing a band of aquamarine colored water. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  11. Bering Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Much of the Bering Sea is clear in this SeaWiFS image. The large expanse of bright aquamarine water is clearly visible. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  12. Active inference, communication and hermeneutics☆

    PubMed Central

    Friston, Karl J.; Frith, Christopher D.

    2015-01-01

    Hermeneutics refers to interpretation and translation of text (typically ancient scriptures) but also applies to verbal and non-verbal communication. In a psychological setting it nicely frames the problem of inferring the intended content of a communication. In this paper, we offer a solution to the problem of neural hermeneutics based upon active inference. In active inference, action fulfils predictions about how we will behave (e.g., predicting we will speak). Crucially, these predictions can be used to predict both self and others – during speaking and listening respectively. Active inference mandates the suppression of prediction errors by updating an internal model that generates predictions – both at fast timescales (through perceptual inference) and slower timescales (through perceptual learning). If two agents adopt the same model, then – in principle – they can predict each other and minimise their mutual prediction errors. Heuristically, this ensures they are singing from the same hymn sheet. This paper builds upon recent work on active inference and communication to illustrate perceptual learning using simulated birdsongs. Our focus here is the neural hermeneutics implicit in learning, where communication facilitates long-term changes in generative models that are trying to predict each other. In other words, communication induces perceptual learning and enables others to (literally) change our minds and vice versa. PMID:25957007

  13. Active inference, communication and hermeneutics.

    PubMed

    Friston, Karl J; Frith, Christopher D

    2015-07-01

    Hermeneutics refers to interpretation and translation of text (typically ancient scriptures) but also applies to verbal and non-verbal communication. In a psychological setting it nicely frames the problem of inferring the intended content of a communication. In this paper, we offer a solution to the problem of neural hermeneutics based upon active inference. In active inference, action fulfils predictions about how we will behave (e.g., predicting we will speak). Crucially, these predictions can be used to predict both self and others--during speaking and listening respectively. Active inference mandates the suppression of prediction errors by updating an internal model that generates predictions--both at fast timescales (through perceptual inference) and slower timescales (through perceptual learning). If two agents adopt the same model, then--in principle--they can predict each other and minimise their mutual prediction errors. Heuristically, this ensures they are singing from the same hymn sheet. This paper builds upon recent work on active inference and communication to illustrate perceptual learning using simulated birdsongs. Our focus here is the neural hermeneutics implicit in learning, where communication facilitates long-term changes in generative models that are trying to predict each other. In other words, communication induces perceptual learning and enables others to (literally) change our minds and vice versa.

  14. Causal inference and developmental psychology.

    PubMed

    Foster, E Michael

    2010-11-01

    Causal inference is of central importance to developmental psychology. Many key questions in the field revolve around improving the lives of children and their families. These include identifying risk factors that if manipulated in some way would foster child development. Such a task inherently involves causal inference: One wants to know whether the risk factor actually causes outcomes. Random assignment is not possible in many instances, and for that reason, psychologists must rely on observational studies. Such studies identify associations, and causal interpretation of such associations requires additional assumptions. Research in developmental psychology generally has relied on various forms of linear regression, but this methodology has limitations for causal inference. Fortunately, methodological developments in various fields are providing new tools for causal inference-tools that rely on more plausible assumptions. This article describes the limitations of regression for causal inference and describes how new tools might offer better causal inference. This discussion highlights the importance of properly identifying covariates to include (and exclude) from the analysis. This discussion considers the directed acyclic graph for use in accomplishing this task. With the proper covariates having been chosen, many of the available methods rely on the assumption of "ignorability." The article discusses the meaning of ignorability and considers alternatives to this assumption, such as instrumental variables estimation. Finally, the article considers the use of the tools discussed in the context of a specific research question, the effect of family structure on child development.

  15. Optimal inference with suboptimal models: Addiction and active Bayesian inference

    PubMed Central

    Schwartenbeck, Philipp; FitzGerald, Thomas H.B.; Mathys, Christoph; Dolan, Ray; Wurst, Friedrich; Kronbichler, Martin; Friston, Karl

    2015-01-01

    When casting behaviour as active (Bayesian) inference, optimal inference is defined with respect to an agent’s beliefs – based on its generative model of the world. This contrasts with normative accounts of choice behaviour, in which optimal actions are considered in relation to the true structure of the environment – as opposed to the agent’s beliefs about worldly states (or the task). This distinction shifts an understanding of suboptimal or pathological behaviour away from aberrant inference as such, to understanding the prior beliefs of a subject that cause them to behave less ‘optimally’ than our prior beliefs suggest they should behave. Put simply, suboptimal or pathological behaviour does not speak against understanding behaviour in terms of (Bayes optimal) inference, but rather calls for a more refined understanding of the subject’s generative model upon which their (optimal) Bayesian inference is based. Here, we discuss this fundamental distinction and its implications for understanding optimality, bounded rationality and pathological (choice) behaviour. We illustrate our argument using addictive choice behaviour in a recently described ‘limited offer’ task. Our simulations of pathological choices and addictive behaviour also generate some clear hypotheses, which we hope to pursue in ongoing empirical work. PMID:25561321

  16. The analysis of historical earthquakes of the North Anatolian Fault in the Marmara Region, Turkey for the last 15 centuries based on intensity and continuous Coulomb scenarios: Implications for the fault geometry and the interaction of individual earthqua

    NASA Astrophysics Data System (ADS)

    Yaltırak, Cenk; Şahin, Murat

    2016-04-01

    In this study we evaluated the historical earthquakes of the Marmara Region totally in three-stages. In first stage, historical earthquakes were compiled from the available catalogues and classified according to their spatial distribution, whereas only the ones, related with the active northern branch of the North Anatolian Fault (NAF) were selected. Then, the next phase of classification was made to relate historical data to the ancient and historical settlements, for which a kind of shake map was produced for each event. In the second stage, three different fault models, suggested for the geometry of the NAF in the Marmara Region, were integrated into a GIS database. Mw magnitudes were calculated for each fault segment by using lengths, seismogenic depths, and slip-rates of fault segments. In the third stage, the revised digital geological map of the Marmara Region were compiled based on 1:500k conventional maps and were used to estimate the Vs30 distribution within a grid of 750x750 m. Modified Mercalli Intensity (MMI) maps were produced for each earthquake scenario, depending on the geometry of different fault models, calculated model magnitudes and intensity distributions. Moreover, we tested the surface ruptures of each earthquake scenarios by using the Coulomb stress change model for historical data covering a time era between AD 478 and 2016 in assumption with a constant horizontal slip rate of 19 mma-1 for all fault segments. As conclusion, the horsetail-fault geometry (Yaltırak, 2002) among all 3 fault models yielded the best fit to the distribution of intensities and coulomb models.

  17. Statistical inference and string theory

    NASA Astrophysics Data System (ADS)

    Heckman, Jonathan J.

    2015-09-01

    In this paper, we expose some surprising connections between string theory and statistical inference. We consider a large collective of agents sweeping out a family of nearby statistical models for an M-dimensional manifold of statistical fitting parameters. When the agents making nearby inferences align along a d-dimensional grid, we find that the pooled probability that the collective reaches a correct inference is the partition function of a nonlinear sigma model in d dimensions. Stability under perturbations to the original inference scheme requires the agents of the collective to distribute along two dimensions. Conformal invariance of the sigma model corresponds to the condition of a stable inference scheme, directly leading to the Einstein field equations for classical gravity. By summing over all possible arrangements of the agents in the collective, we reach a string theory. We also use this perspective to quantify how much an observer can hope to learn about the internal geometry of a superstring compactification. Finally, we present some brief speculative remarks on applications to the AdS/CFT correspondence and Lorentzian signature space-times.

  18. Locative inferences in medical texts.

    PubMed

    Mayer, P S; Bailey, G H; Mayer, R J; Hillis, A; Dvoracek, J E

    1987-06-01

    Medical research relies on epidemiological studies conducted on a large set of clinical records that have been collected from physicians recording individual patient observations. These clinical records are recorded for the purpose of individual care of the patient with little consideration for their use by a biostatistician interested in studying a disease over a large population. Natural language processing of clinical records for epidemiological studies must deal with temporal, locative, and conceptual issues. This makes text understanding and data extraction of clinical records an excellent area for applied research. While much has been done in making temporal or conceptual inferences in medical texts, parallel work in locative inferences has not been done. This paper examines the locative inferences as well as the integration of temporal, locative, and conceptual issues in the clinical record understanding domain by presenting an application that utilizes two key concepts in its parsing strategy--a knowledge-based parsing strategy and a minimal lexicon.

  19. Processing the Bouguer anomaly map of Biga and the surrounding area by the cellular neural network: application to the southwestern Marmara region

    NASA Astrophysics Data System (ADS)

    Aydogan, D.

    2007-04-01

    An image processing technique called the cellular neural network (CNN) approach is used in this study to locate geological features giving rise to gravity anomalies such as faults or the boundary of two geologic zones. CNN is a stochastic image processing technique based on template optimization using the neighborhood relationships of cells. These cells can be characterized by a functional block diagram that is typical of neural network theory. The functionality of CNN is described in its entirety by a number of small matrices (A, B and I) called the cloning template. CNN can also be considered to be a nonlinear convolution of these matrices. This template describes the strength of the nearest neighbor interconnections in the network. The recurrent perceptron learning algorithm (RPLA) is used in optimization of cloning template. The CNN and standard Canny algorithms were first tested on two sets of synthetic gravity data with the aim of checking the reliability of the proposed approach. The CNN method was compared with classical derivative techniques by applying the cross-correlation method (CC) to the same anomaly map as this latter approach can detect some features that are difficult to identify on the Bouguer anomaly maps. This approach was then applied to the Bouguer anomaly map of Biga and its surrounding area, in Turkey. Structural features in the area between Bandirma, Biga, Yenice and Gonen in the southwest Marmara region are investigated by applying the CNN and CC to the Bouguer anomaly map. Faults identified by these algorithms are generally in accordance with previously mapped surface faults. These examples show that the geologic boundaries can be detected from Bouguer anomaly maps using the cloning template approach. A visual evaluation of the outputs of the CNN and CC approaches is carried out, and the results are compared with each other. This approach provides quantitative solutions based on just a few assumptions, which makes the method more

  20. Two Sea-Level Challenges

    NASA Astrophysics Data System (ADS)

    Galvin, C.

    2008-12-01

    "No place on the sandy ocean shores of the world has been shown to be eroding because of sea level rise." This statement appeared nearly 19 years ago in bold print at the top of the page in a brief article published in Shore and Beach (Galvin,1990). The term "sea level rise" was defined in 1990 as follows: "In this statement, "sea level rise" has the meaning that the average person on the street usually attaches to that term. That is, sea level is rising; not, as in some places like the Mississippi River delta, land level is sinking." While still a subject of controversy, it is now (2008) increasingly plausible (Tornqvist et al,2008) that damage from Hurricane Katrina was significantly worse on the Mississippi River delta because floodwaters exploited wetlands and levees whose elevations had been lowered by decades of compaction in the underlying soil. (1) "Sea level" commonly appears in the literature as "relative sea level rise", occurring that way in 711 publications between 1980 and 2009 (GeoRef database on 8 Sep 08). "Relative sea level rise" does not appear in the 2005 AGI Glossary. The nearest Glossary term is "relative change in sea level", but that term occurs in only 12 publications between 1980 and 2009. The Glossary defines this term in a sequence stratigraphy sense, which infers that "relative sea level rise" is the sum of bottom subsidence and eustatic sea level rise. In plain English, "relative sea level rise" means "water depth increase". For present day coastal environments, "relative sea level rise" is commonly used where eustatic sea level rise is less than subsidence, that is, where the magnitude of actual sea level rise is smaller than the magnitude of subsidence. In that situation, "relative sea level rise" misleads both the average person and the scientist who is not a coastal geologist. Thus, the first challenge is to abandon "relative sea level rise" in favor of "water depth increase", in order that the words accurately descibe what happens

  1. How Forgetting Aids Heuristic Inference

    ERIC Educational Resources Information Center

    Schooler, Lael J.; Hertwig, Ralph

    2005-01-01

    Some theorists, ranging from W. James (1890) to contemporary psychologists, have argued that forgetting is the key to proper functioning of memory. The authors elaborate on the notion of beneficial forgetting by proposing that loss of information aids inference heuristics that exploit mnemonic information. To this end, the authors bring together 2…

  2. Science Shorts: Observation versus Inference

    ERIC Educational Resources Information Center

    Leager, Craig R.

    2008-01-01

    When you observe something, how do you know for sure what you are seeing, feeling, smelling, or hearing? Asking students to think critically about their encounters with the natural world will help to strengthen their understanding and application of the science-process skills of observation and inference. In the following lesson, students make…

  3. The mechanisms of temporal inference

    NASA Technical Reports Server (NTRS)

    Fox, B. R.; Green, S. R.

    1987-01-01

    The properties of a temporal language are determined by its constituent elements: the temporal objects which it can represent, the attributes of those objects, the relationships between them, the axioms which define the default relationships, and the rules which define the statements that can be formulated. The methods of inference which can be applied to a temporal language are derived in part from a small number of axioms which define the meaning of equality and order and how those relationships can be propagated. More complex inferences involve detailed analysis of the stated relationships. Perhaps the most challenging area of temporal inference is reasoning over disjunctive temporal constraints. Simple forms of disjunction do not sufficiently increase the expressive power of a language while unrestricted use of disjunction makes the analysis NP-hard. In many cases a set of disjunctive constraints can be converted to disjunctive normal form and familiar methods of inference can be applied to the conjunctive sub-expressions. This process itself is NP-hard but it is made more tractable by careful expansion of a tree-structured search space.

  4. Statistical inference and Aristotle's Rhetoric.

    PubMed

    Macdonald, Ranald R

    2004-11-01

    Formal logic operates in a closed system where all the information relevant to any conclusion is present, whereas this is not the case when one reasons about events and states of the world. Pollard and Richardson drew attention to the fact that the reasoning behind statistical tests does not lead to logically justifiable conclusions. In this paper statistical inferences are defended not by logic but by the standards of everyday reasoning. Aristotle invented formal logic, but argued that people mostly get at the truth with the aid of enthymemes--incomplete syllogisms which include arguing from examples, analogies and signs. It is proposed that statistical tests work in the same way--in that they are based on examples, invoke the analogy of a model and use the size of the effect under test as a sign that the chance hypothesis is unlikely. Of existing theories of statistical inference only a weak version of Fisher's takes this into account. Aristotle anticipated Fisher by producing an argument of the form that there were too many cases in which an outcome went in a particular direction for that direction to be plausibly attributed to chance. We can therefore conclude that Aristotle would have approved of statistical inference and there is a good reason for calling this form of statistical inference classical.

  5. Word Learning as Bayesian Inference

    ERIC Educational Resources Information Center

    Xu, Fei; Tenenbaum, Joshua B.

    2007-01-01

    The authors present a Bayesian framework for understanding how adults and children learn the meanings of words. The theory explains how learners can generalize meaningfully from just one or a few positive examples of a novel word's referents, by making rational inductive inferences that integrate prior knowledge about plausible word meanings with…

  6. Starfish: Robust spectroscopic inference tools

    NASA Astrophysics Data System (ADS)

    Czekala, Ian; Andrews, Sean M.; Mandel, Kaisey S.; Hogg, David W.; Green, Gregory M.

    2015-05-01

    Starfish is a set of tools used for spectroscopic inference. It robustly determines stellar parameters using high resolution spectral models and uses Markov Chain Monte Carlo (MCMC) to explore the full posterior probability distribution of the stellar parameters. Additional potential applications include other types of spectra, such as unresolved stellar clusters or supernovae spectra.

  7. Improving Explanatory Inferences from Assessments

    ERIC Educational Resources Information Center

    Diakow, Ronli Phyllis

    2013-01-01

    This dissertation comprises three papers that propose, discuss, and illustrate models to make improved inferences about research questions regarding student achievement in education. Addressing the types of questions common in educational research today requires three different "extensions" to traditional educational assessment: (1)…

  8. Perceptual Inference and Autistic Traits

    ERIC Educational Resources Information Center

    Skewes, Joshua C; Jegindø, Else-Marie; Gebauer, Line

    2015-01-01

    Autistic people are better at perceiving details. Major theories explain this in terms of bottom-up sensory mechanisms or in terms of top-down cognitive biases. Recently, it has become possible to link these theories within a common framework. This framework assumes that perception is implicit neural inference, combining sensory evidence with…

  9. Caspian Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this Moderate-resolution Imaging Spectroradiometer (MODIS) image from December 3, 2001, winter sea ice can be seen forming in the shallow waters of the northern Caspian (left) and Aral (upper right) Seas. Despite the inflow of the Volga River (upper left), the northern portion of the Caspian Sea averages only 17 feet in depth, and responds to the region's continental climate, which is cold in winter and hot and dry in the summer. The southern part of the Sea is deeper and remains ice-free throughout the winter. The dirty appearance of the ice may be due to sediment in the water, but may also be due to wind-driven dust. The wind in the region can blow at hurricane-force strength and can cause the ice to pile up in hummocks that are anchored to the sea bottom. The eastern portion of the Aral Sea is also beginning to freeze. At least two characteristics of the Aral Sea 'compete' in determining whether its waters will freeze. The Sea is shallow, which increases the likelihood of freezing, but it is also very salty, which means that lower temperatures are required to freeze it than would be required for fresh water. With average December temperatures of 18oF, it's clearly cold enough to allow ice to form. As the waters that feed the Aral Sea continue to be diverted for agriculture, the Sea becomes shallower and the regional climate becomes even more continental. This is because large bodies of water absorb and retain heat, moderating seasonal changes in temperature. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  10. Towards General Algorithms for Grammatical Inference

    NASA Astrophysics Data System (ADS)

    Clark, Alexander

    Many algorithms for grammatical inference can be viewed as instances of a more general algorithm which maintains a set of primitive elements, which distributionally define sets of strings, and a set of features or tests that constrain various inference rules. Using this general framework, which we cast as a process of logical inference, we re-analyse Angluin's famous lstar algorithm and several recent algorithms for the inference of context-free grammars and multiple context-free grammars. Finally, to illustrate the advantages of this approach, we extend it to the inference of functional transductions from positive data only, and we present a new algorithm for the inference of finite state transducers.

  11. Statistical learning and selective inference

    PubMed Central

    Taylor, Jonathan; Tibshirani, Robert J.

    2015-01-01

    We describe the problem of “selective inference.” This addresses the following challenge: Having mined a set of data to find potential associations, how do we properly assess the strength of these associations? The fact that we have “cherry-picked”—searched for the strongest associations—means that we must set a higher bar for declaring significant the associations that we see. This challenge becomes more important in the era of big data and complex statistical modeling. The cherry tree (dataset) can be very large and the tools for cherry picking (statistical learning methods) are now very sophisticated. We describe some recent new developments in selective inference and illustrate their use in forward stepwise regression, the lasso, and principal components analysis. PMID:26100887

  12. Causal inference based on counterfactuals

    PubMed Central

    Höfler, M

    2005-01-01

    Background The counterfactual or potential outcome model has become increasingly standard for causal inference in epidemiological and medical studies. Discussion This paper provides an overview on the counterfactual and related approaches. A variety of conceptual as well as practical issues when estimating causal effects are reviewed. These include causal interactions, imperfect experiments, adjustment for confounding, time-varying exposures, competing risks and the probability of causation. It is argued that the counterfactual model of causal effects captures the main aspects of causality in health sciences and relates to many statistical procedures. Summary Counterfactuals are the basis of causal inference in medicine and epidemiology. Nevertheless, the estimation of counterfactual differences pose several difficulties, primarily in observational studies. These problems, however, reflect fundamental barriers only when learning from observations, and this does not invalidate the counterfactual concept. PMID:16159397

  13. Statistical learning and selective inference.

    PubMed

    Taylor, Jonathan; Tibshirani, Robert J

    2015-06-23

    We describe the problem of "selective inference." This addresses the following challenge: Having mined a set of data to find potential associations, how do we properly assess the strength of these associations? The fact that we have "cherry-picked"--searched for the strongest associations--means that we must set a higher bar for declaring significant the associations that we see. This challenge becomes more important in the era of big data and complex statistical modeling. The cherry tree (dataset) can be very large and the tools for cherry picking (statistical learning methods) are now very sophisticated. We describe some recent new developments in selective inference and illustrate their use in forward stepwise regression, the lasso, and principal components analysis.

  14. Inferring Centrality from Network Snapshots

    NASA Astrophysics Data System (ADS)

    Shao, Haibin; Mesbahi, Mehran; Li, Dewei; Xi, Yugeng

    2017-01-01

    The topology and dynamics of a complex network shape its functionality. However, the topologies of many large-scale networks are either unavailable or incomplete. Without the explicit knowledge of network topology, we show how the data generated from the network dynamics can be utilised to infer the tempo centrality, which is proposed to quantify the influence of nodes in a consensus network. We show that the tempo centrality can be used to construct an accurate estimate of both the propagation rate of influence exerted on consensus networks and the Kirchhoff index of the underlying graph. Moreover, the tempo centrality also encodes the disturbance rejection of nodes in a consensus network. Our findings provide an approach to infer the performance of a consensus network from its temporal data.

  15. Network Plasticity as Bayesian Inference

    PubMed Central

    Legenstein, Robert; Maass, Wolfgang

    2015-01-01

    General results from statistical learning theory suggest to understand not only brain computations, but also brain plasticity as probabilistic inference. But a model for that has been missing. We propose that inherently stochastic features of synaptic plasticity and spine motility enable cortical networks of neurons to carry out probabilistic inference by sampling from a posterior distribution of network configurations. This model provides a viable alternative to existing models that propose convergence of parameters to maximum likelihood values. It explains how priors on weight distributions and connection probabilities can be merged optimally with learned experience, how cortical networks can generalize learned information so well to novel experiences, and how they can compensate continuously for unforeseen disturbances of the network. The resulting new theory of network plasticity explains from a functional perspective a number of experimental data on stochastic aspects of synaptic plasticity that previously appeared to be quite puzzling. PMID:26545099

  16. Bayesian Inference on Proportional Elections

    PubMed Central

    Brunello, Gabriel Hideki Vatanabe; Nakano, Eduardo Yoshio

    2015-01-01

    Polls for majoritarian voting systems usually show estimates of the percentage of votes for each candidate. However, proportional vote systems do not necessarily guarantee the candidate with the most percentage of votes will be elected. Thus, traditional methods used in majoritarian elections cannot be applied on proportional elections. In this context, the purpose of this paper was to perform a Bayesian inference on proportional elections considering the Brazilian system of seats distribution. More specifically, a methodology to answer the probability that a given party will have representation on the chamber of deputies was developed. Inferences were made on a Bayesian scenario using the Monte Carlo simulation technique, and the developed methodology was applied on data from the Brazilian elections for Members of the Legislative Assembly and Federal Chamber of Deputies in 2010. A performance rate was also presented to evaluate the efficiency of the methodology. Calculations and simulations were carried out using the free R statistical software. PMID:25786259

  17. System Support for Forensic Inference

    NASA Astrophysics Data System (ADS)

    Gehani, Ashish; Kirchner, Florent; Shankar, Natarajan

    Digital evidence is playing an increasingly important role in prosecuting crimes. The reasons are manifold: financially lucrative targets are now connected online, systems are so complex that vulnerabilities abound and strong digital identities are being adopted, making audit trails more useful. If the discoveries of forensic analysts are to hold up to scrutiny in court, they must meet the standard for scientific evidence. Software systems are currently developed without consideration of this fact. This paper argues for the development of a formal framework for constructing “digital artifacts” that can serve as proxies for physical evidence; a system so imbued would facilitate sound digital forensic inference. A case study involving a filesystem augmentation that provides transparent support for forensic inference is described.

  18. Inferring Centrality from Network Snapshots

    PubMed Central

    Shao, Haibin; Mesbahi, Mehran; Li, Dewei; Xi, Yugeng

    2017-01-01

    The topology and dynamics of a complex network shape its functionality. However, the topologies of many large-scale networks are either unavailable or incomplete. Without the explicit knowledge of network topology, we show how the data generated from the network dynamics can be utilised to infer the tempo centrality, which is proposed to quantify the influence of nodes in a consensus network. We show that the tempo centrality can be used to construct an accurate estimate of both the propagation rate of influence exerted on consensus networks and the Kirchhoff index of the underlying graph. Moreover, the tempo centrality also encodes the disturbance rejection of nodes in a consensus network. Our findings provide an approach to infer the performance of a consensus network from its temporal data. PMID:28098166

  19. Bayesian inference for agreement measures.

    PubMed

    Vidal, Ignacio; de Castro, Mário

    2016-08-25

    The agreement of different measurement methods is an important issue in several disciplines like, for example, Medicine, Metrology, and Engineering. In this article, some agreement measures, common in the literature, were analyzed from a Bayesian point of view. Posterior inferences for such agreement measures were obtained based on well-known Bayesian inference procedures for the bivariate normal distribution. As a consequence, a general, simple, and effective method is presented, which does not require Markov Chain Monte Carlo methods and can be applied considering a great variety of prior distributions. Illustratively, the method was exemplified using five objective priors for the bivariate normal distribution. A tool for assessing the adequacy of the model is discussed. Results from a simulation study and an application to a real dataset are also reported.

  20. Inference of reversible tree languages.

    PubMed

    López, Damián; Sempere, José M; García, Pedro

    2004-08-01

    In this paper, we study the notion of k-reversibility and k-testability when regular tree languages are involved. We present an inference algorithm for learning a k-testable tree language that runs in polynomial time with respect to the size of the sample used. We also study the tree language classes in relation to other well known ones, and some properties of these languages are proven.

  1. Fast, Flexible, Rational Inductive Inference

    DTIC Science & Technology

    2013-08-23

    learning phonetic categories – the sounds that make up speech – learning the words that those sounds appear in provides sufficiently strong constraints...first to be able to infer realistic phonetic categories directly from simulated speech data. Objective 2.2: Forming feature-based representations...lexicon in phonetic category acquisition. Psychological Review. Griffiths, T. L., Austerweil, J. L., & Berthiaume, V. G. (2012). Comparing the

  2. Cortical circuits for perceptual inference.

    PubMed

    Friston, Karl; Kiebel, Stefan

    2009-10-01

    This paper assumes that cortical circuits have evolved to enable inference about the causes of sensory input received by the brain. This provides a principled specification of what neural circuits have to achieve. Here, we attempt to address how the brain makes inferences by casting inference as an optimisation problem. We look at how the ensuing recognition dynamics could be supported by directed connections and message-passing among neuronal populations, given our knowledge of intrinsic and extrinsic neuronal connections. We assume that the brain models the world as a dynamic system, which imposes causal structure on the sensorium. Perception is equated with the optimisation or inversion of this internal model, to explain sensory input. Given a model of how sensory data are generated, we use a generic variational approach to model inversion to furnish equations that prescribe recognition; i.e., the dynamics of neuronal activity that represents the causes of sensory input. Here, we focus on a model whose hierarchical and dynamical structure enables simulated brains to recognise and predict sequences of sensory states. We first review these models and their inversion under a variational free-energy formulation. We then show that the brain has the necessary infrastructure to implement this inversion and present stimulations using synthetic birds that generate and recognise birdsongs.

  3. An introduction to causal inference.

    PubMed

    Pearl, Judea

    2010-02-26

    This paper summarizes recent advances in causal inference and underscores the paradigmatic shifts that must be undertaken in moving from traditional statistical analysis to causal analysis of multivariate data. Special emphasis is placed on the assumptions that underlie all causal inferences, the languages used in formulating those assumptions, the conditional nature of all causal and counterfactual claims, and the methods that have been developed for the assessment of such claims. These advances are illustrated using a general theory of causation based on the Structural Causal Model (SCM) described in Pearl (2000a), which subsumes and unifies other approaches to causation, and provides a coherent mathematical foundation for the analysis of causes and counterfactuals. In particular, the paper surveys the development of mathematical tools for inferring (from a combination of data and assumptions) answers to three types of causal queries: those about (1) the effects of potential interventions, (2) probabilities of counterfactuals, and (3) direct and indirect effects (also known as "mediation"). Finally, the paper defines the formal and conceptual relationships between the structural and potential-outcome frameworks and presents tools for a symbiotic analysis that uses the strong features of both. The tools are demonstrated in the analyses of mediation, causes of effects, and probabilities of causation.

  4. Children's and adults' evaluation of the certainty of deductive inferences, inductive inferences, and guesses.

    PubMed

    Pillow, Bradford H

    2002-01-01

    Two experiments investigated kindergarten through fourth-grade children's and adults' (N = 128) ability to (1) evaluate the certainty of deductive inferences, inductive inferences, and guesses; and (2) explain the origins of inferential knowledge. When judging their own cognitive state, children in first grade and older rated deductive inferences as more certain than guesses; but when judging another person's knowledge, children did not distinguish valid inferences from invalid inferences and guesses until fourth grade. By third grade, children differentiated their own deductive inferences from inductive inferences and guesses, but only adults both differentiated deductive inferences from inductive inferences and differentiated inductive inferences from guesses. Children's recognition of their own inferences may contribute to the development of knowledge about cognitive processes, scientific reasoning, and a constructivist epistemology.

  5. Evolution of the plankton paleome in the Black Sea from the Deglacial to Anthropocene.

    PubMed

    Coolen, Marco J L; Orsi, William D; Balkema, Cherel; Quince, Christopher; Harris, Keith; Sylva, Sean P; Filipova-Marinova, Mariana; Giosan, Liviu

    2013-05-21

    The complex interplay of climate shifts over Eurasia and global sea level changes modulates freshwater and saltwater inputs to the Black Sea. The dynamics of the hydrologic changes from the Late Glacial into the Holocene remain a matter of debate, and information on how these changes affected the ecology of the Black Sea is sparse. Here we used Roche 454 next-generation pyrosequencing of sedimentary 18S rRNA genes to reconstruct the plankton community structure in the Black Sea over the last ca. 11,400 y. We found that 150 of 2,710 species showed a statistically significant response to four environmental stages. Freshwater chlorophytes were the best indicator species for lacustrine conditions (>9.0 ka B.P.), although the copresence of previously unidentified marine taxa indicated that the Black Sea might have been influenced to some extent by the Marmara Sea since at least 9.6 ka calendar (cal) B.P. Dinoflagellates, cercozoa, eustigmatophytes, and haptophytes responded most dramatically to the gradual increase in salinity after the latest marine reconnection and during the warm and moist mid-Holocene climatic optimum. According to paired analysis of deuterium/hydrogen (D/H) isotope ratios in fossil alkenones, salinity increased rapidly with the onset of the dry Subboreal after ~5.2 ka B.P., leading to an increase in marine fungi and the first occurrence of marine copepods. A gradual succession of dinoflagellates, diatoms, and chrysophytes occurred during the refreshening after ~2.5 ka cal B.P. with the onset of the cool and wet Subatlantic climate and recent anthropogenic perturbations.

  6. Arabian Sea

    Atmospheric Science Data Center

    2013-04-16

    ... sometimes results in copious phytoplankton production and oxygen depletion of the subsurface waters. Although red phytoplankton fluorescences have been associated with the low oxygen concentrations in the intermediate and deep waters of the Arabian Sea, ...

  7. Sea Legs

    NASA Astrophysics Data System (ADS)

    Macdonald, Kenneth C.

    Forty-foot, storm-swept seas, Spitzbergen polar bears roaming vast expanses of Arctic ice, furtive exchanges of forbidden manuscripts in Cold War Moscow, the New York city fashion scene, diving in mini-subs to the sea floor hot srings, life with the astronauts, romance and heartbreak, and invading the last bastions of male exclusivity: all are present in this fast-moving, non-fiction account of one woman' fascinating adventures in the world of marine geology and oceanography.

  8. Statistical inference for inverse problems

    NASA Astrophysics Data System (ADS)

    Bissantz, Nicolai; Holzmann, Hajo

    2008-06-01

    In this paper we study statistical inference for certain inverse problems. We go beyond mere estimation purposes and review and develop the construction of confidence intervals and confidence bands in some inverse problems, including deconvolution and the backward heat equation. Further, we discuss the construction of certain hypothesis tests, in particular concerning the number of local maxima of the unknown function. The methods are illustrated in a case study, where we analyze the distribution of heliocentric escape velocities of galaxies in the Centaurus galaxy cluster, and provide statistical evidence for its bimodality.

  9. sick: The Spectroscopic Inference Crank

    NASA Astrophysics Data System (ADS)

    Casey, Andrew R.

    2016-03-01

    There exists an inordinate amount of spectral data in both public and private astronomical archives that remain severely under-utilized. The lack of reliable open-source tools for analyzing large volumes of spectra contributes to this situation, which is poised to worsen as large surveys successively release orders of magnitude more spectra. In this article I introduce sick, the spectroscopic inference crank, a flexible and fast Bayesian tool for inferring astrophysical parameters from spectra. sick is agnostic to the wavelength coverage, resolving power, or general data format, allowing any user to easily construct a generative model for their data, regardless of its source. sick can be used to provide a nearest-neighbor estimate of model parameters, a numerically optimized point estimate, or full Markov Chain Monte Carlo sampling of the posterior probability distributions. This generality empowers any astronomer to capitalize on the plethora of published synthetic and observed spectra, and make precise inferences for a host of astrophysical (and nuisance) quantities. Model intensities can be reliably approximated from existing grids of synthetic or observed spectra using linear multi-dimensional interpolation, or a Cannon-based model. Additional phenomena that transform the data (e.g., redshift, rotational broadening, continuum, spectral resolution) are incorporated as free parameters and can be marginalized away. Outlier pixels (e.g., cosmic rays or poorly modeled regimes) can be treated with a Gaussian mixture model, and a noise model is included to account for systematically underestimated variance. Combining these phenomena into a scalar-justified, quantitative model permits precise inferences with credible uncertainties on noisy data. I describe the common model features, the implementation details, and the default behavior, which is balanced to be suitable for most astronomical applications. Using a forward model on low-resolution, high signal

  10. Universum Inference and Corpus Homogeneity

    NASA Astrophysics Data System (ADS)

    Vogel, Carl; Lynch, Gerard; Janssen, Jerom

    Universum Inference is re-interpreted for assessment of corpus homogeneity in computational stylometry. Recent stylometric research quantifies strength of characterization within dramatic works by assessing the homogeneity of corpora associated with dramatic personas. A methodological advance is suggested to mitigate the potential for the assessment of homogeneity to be achieved by chance. Baseline comparison analysis is constructed for contributions to debates by nonfictional participants: the corpus analyzed consists of transcripts of US Presidential and Vice-Presidential debates from the 2000 election cycle. The corpus is also analyzed in translation to Italian, Spanish and Portuguese. Adding randomized categories makes assessments of homogeneity more conservative.

  11. Bayesian inference for OPC modeling

    NASA Astrophysics Data System (ADS)

    Burbine, Andrew; Sturtevant, John; Fryer, David; Smith, Bruce W.

    2016-03-01

    The use of optical proximity correction (OPC) demands increasingly accurate models of the photolithographic process. Model building and inference techniques in the data science community have seen great strides in the past two decades which make better use of available information. This paper aims to demonstrate the predictive power of Bayesian inference as a method for parameter selection in lithographic models by quantifying the uncertainty associated with model inputs and wafer data. Specifically, the method combines the model builder's prior information about each modelling assumption with the maximization of each observation's likelihood as a Student's t-distributed random variable. Through the use of a Markov chain Monte Carlo (MCMC) algorithm, a model's parameter space is explored to find the most credible parameter values. During parameter exploration, the parameters' posterior distributions are generated by applying Bayes' rule, using a likelihood function and the a priori knowledge supplied. The MCMC algorithm used, an affine invariant ensemble sampler (AIES), is implemented by initializing many walkers which semiindependently explore the space. The convergence of these walkers to global maxima of the likelihood volume determine the parameter values' highest density intervals (HDI) to reveal champion models. We show that this method of parameter selection provides insights into the data that traditional methods do not and outline continued experiments to vet the method.

  12. Bayesian inference for radio observations

    NASA Astrophysics Data System (ADS)

    Lochner, Michelle; Natarajan, Iniyan; Zwart, Jonathan T. L.; Smirnov, Oleg; Bassett, Bruce A.; Oozeer, Nadeem; Kunz, Martin

    2015-06-01

    New telescopes like the Square Kilometre Array (SKA) will push into a new sensitivity regime and expose systematics, such as direction-dependent effects, that could previously be ignored. Current methods for handling such systematics rely on alternating best estimates of instrumental calibration and models of the underlying sky, which can lead to inadequate uncertainty estimates and biased results because any correlations between parameters are ignored. These deconvolution algorithms produce a single image that is assumed to be a true representation of the sky, when in fact it is just one realization of an infinite ensemble of images compatible with the noise in the data. In contrast, here we report a Bayesian formalism that simultaneously infers both systematics and science. Our technique, Bayesian Inference for Radio Observations (BIRO), determines all parameters directly from the raw data, bypassing image-making entirely, by sampling from the joint posterior probability distribution. This enables it to derive both correlations and accurate uncertainties, making use of the flexible software MEQTREES to model the sky and telescope simultaneously. We demonstrate BIRO with two simulated sets of Westerbork Synthesis Radio Telescope data sets. In the first, we perform joint estimates of 103 scientific (flux densities of sources) and instrumental (pointing errors, beamwidth and noise) parameters. In the second example, we perform source separation with BIRO. Using the Bayesian evidence, we can accurately select between a single point source, two point sources and an extended Gaussian source, allowing for `super-resolution' on scales much smaller than the synthesized beam.

  13. Quantum Inference on Bayesian Networks

    NASA Astrophysics Data System (ADS)

    Yoder, Theodore; Low, Guang Hao; Chuang, Isaac

    2014-03-01

    Because quantum physics is naturally probabilistic, it seems reasonable to expect physical systems to describe probabilities and their evolution in a natural fashion. Here, we use quantum computation to speedup sampling from a graphical probability model, the Bayesian network. A specialization of this sampling problem is approximate Bayesian inference, where the distribution on query variables is sampled given the values e of evidence variables. Inference is a key part of modern machine learning and artificial intelligence tasks, but is known to be NP-hard. Classically, a single unbiased sample is obtained from a Bayesian network on n variables with at most m parents per node in time (nmP(e) - 1 / 2) , depending critically on P(e) , the probability the evidence might occur in the first place. However, by implementing a quantum version of rejection sampling, we obtain a square-root speedup, taking (n2m P(e) -1/2) time per sample. The speedup is the result of amplitude amplification, which is proving to be broadly applicable in sampling and machine learning tasks. In particular, we provide an explicit and efficient circuit construction that implements the algorithm without the need for oracle access.

  14. Dopamine, Affordance and Active Inference

    PubMed Central

    Friston, Karl J.; Shiner, Tamara; FitzGerald, Thomas; Galea, Joseph M.; Adams, Rick; Brown, Harriet; Dolan, Raymond J.; Moran, Rosalyn; Stephan, Klaas Enno; Bestmann, Sven

    2012-01-01

    The role of dopamine in behaviour and decision-making is often cast in terms of reinforcement learning and optimal decision theory. Here, we present an alternative view that frames the physiology of dopamine in terms of Bayes-optimal behaviour. In this account, dopamine controls the precision or salience of (external or internal) cues that engender action. In other words, dopamine balances bottom-up sensory information and top-down prior beliefs when making hierarchical inferences (predictions) about cues that have affordance. In this paper, we focus on the consequences of changing tonic levels of dopamine firing using simulations of cued sequential movements. Crucially, the predictions driving movements are based upon a hierarchical generative model that infers the context in which movements are made. This means that we can confuse agents by changing the context (order) in which cues are presented. These simulations provide a (Bayes-optimal) model of contextual uncertainty and set switching that can be quantified in terms of behavioural and electrophysiological responses. Furthermore, one can simulate dopaminergic lesions (by changing the precision of prediction errors) to produce pathological behaviours that are reminiscent of those seen in neurological disorders such as Parkinson's disease. We use these simulations to demonstrate how a single functional role for dopamine at the synaptic level can manifest in different ways at the behavioural level. PMID:22241972

  15. Sea Ice

    NASA Technical Reports Server (NTRS)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  16. Aral Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This series of MODIS images shows the dwindling Aral Sea. Once one of the world's largest freshwater lakes, the Aral Sea has decreased by as much as 60% over the past few decades due to diversion of the water to grow cotton and rice. These diversion have dropped the lake levels, increased salinity, and nearly decimated the fishing industry. The previous extent of the lake is clearly visible as a whitish perimeter in these image from April 16, May 18, and June 3, 2002. s. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  17. Black Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Black Sea in eastern Russia is experiencing an ongoing phytoplankton bloom. This image, the most recent in a series that began in early may, shows the waters to be even more colorful than before. part of the increased brightness may be due to the presence of sun glint , especially in the center of the sea. However, more organisms appear to be present as well, their photosynthetic pigments reflecting different wavelengths of light.This Moderate Resolution Imaging Spectroradiometer (MODIS) image was captured on June 15, 2002.

  18. Spontaneous Trait Inferences on Social Media

    PubMed Central

    Utz, Sonja

    2016-01-01

    The present research investigates whether spontaneous trait inferences occur under conditions characteristic of social media and networking sites: nonextreme, ostensibly self-generated content, simultaneous presentation of multiple cues, and self-paced browsing. We used an established measure of trait inferences (false recognition paradigm) and a direct assessment of impressions. Without being asked to do so, participants spontaneously formed impressions of people whose status updates they saw. Our results suggest that trait inferences occurred from nonextreme self-generated content, which is commonly found in social media updates (Experiment 1) and when nine status updates from different people were presented in parallel (Experiment 2). Although inferences did occur during free browsing, the results suggest that participants did not necessarily associate the traits with the corresponding status update authors (Experiment 3). Overall, the findings suggest that spontaneous trait inferences occur on social media. We discuss implications for online communication and research on spontaneous trait inferences. PMID:28123646

  19. Inferring echolocation in ancient bats.

    PubMed

    Simmons, Nancy B; Seymour, Kevin L; Habersetzer, Jörg; Gunnell, Gregg F

    2010-08-19

    Laryngeal echolocation, used by most living bats to form images of their surroundings and to detect and capture flying prey, is considered to be a key innovation for the evolutionary success of bats, and palaeontologists have long sought osteological correlates of echolocation that can be used to infer the behaviour of fossil bats. Veselka et al. argued that the most reliable trait indicating echolocation capabilities in bats is an articulation between the stylohyal bone (part of the hyoid apparatus that supports the throat and larynx) and the tympanic bone, which forms the floor of the middle ear. They examined the oldest and most primitive known bat, Onychonycteris finneyi (early Eocene, USA), and argued that it showed evidence of this stylohyal-tympanic articulation, from which they concluded that O. finneyi may have been capable of echolocation. We disagree with their interpretation of key fossil data and instead argue that O. finneyi was probably not an echolocating bat.

  20. Motion Inference During +Gz Acceleration

    DTIC Science & Technology

    2006-09-01

    AFRL-HW-WP-TP-2006-0091 Motion Inference During +Gz Acceleration Lloyd D . Tripp Jr. Richard A. McKinley Robert L. Esken Air Force Research Laboratory...5c. PROGRAM ELEMENT NUMBER 62202F 6. AUTHOR(S) 5d. PROJECT NUMBER Lloyd D . Tripp Jr 7184 Richard A. McKinley 5e. TASK NUMBER Robert L. Esken 03 5f...CD A Cj CL.C2 C 0~ 0. D 0 0~G)C00.E)’ca)4-100 ( 0 Eo12 E a 0 0L0mm 0a0 " C0 U) U) LUr o CLI.,a @ .- . : ) 0 " 0 C CL.. 70 E- 0 M 0.0 toE-C .- 0)c .2 0UL

  1. Inferred properties of stellar granulation

    SciTech Connect

    Gray, D.F.; Toner, C.G.

    1985-06-01

    Apparent characteristics of stellar granulation in F and G main-sequence stars are inferred directly from observed spectral-line asymmetries and from comparisons of numerical simulations with the observations: (1) the apparent granulation velocity increases with effective temperature, (2) the dispersion of granule velocities about their mean velocity of rise increases with the apparent granulation velocity, (3) the mean velocity of rise of granules must be less than the total line broadening, (4) the apparent velocity difference between granules and dark lanes corresponds to the granulation velocity deduced from stellar line bisectors, (5) the dark lanes show velocities of fall approximately twice as large as the granule rise velocities, (6) the light contributed to the stellar flux by the granules is four to ten times more than the light from the dark lanes. Stellar rotation is predicted to produce distortions in the line bisectors which may give information on the absolute velocity displacements of the line bisectors. 37 references.

  2. Synaptic Computation Underlying Probabilistic Inference

    PubMed Central

    Soltani, Alireza; Wang, Xiao-Jing

    2010-01-01

    In this paper we propose that synapses may be the workhorse of neuronal computations that underlie probabilistic reasoning. We built a neural circuit model for probabilistic inference when information provided by different sensory cues needs to be integrated, and the predictive powers of individual cues about an outcome are deduced through experience. We found that bounded synapses naturally compute, through reward-dependent plasticity, the posterior probability that a choice alternative is correct given that a cue is presented. Furthermore, a decision circuit endowed with such synapses makes choices based on the summated log posterior odds and performs near-optimal cue combination. The model is validated by reproducing salient observations of, and provide insights into, a monkey experiment using a categorization task. Our model thus suggests a biophysical instantiation of the Bayesian decision rule, while predicting important deviations from it similar to ‘base-rate neglect’ observed in human studies when alternatives have unequal priors. PMID:20010823

  3. Sea Clutter

    DTIC Science & Technology

    1990-09-28

    OE-10, 47i- 476, (1985). 15. S. Tang and 0. H. Shemdin , "Measurement of High-frequency Waves using a Wave Fol- lower," J. Geophys. Res. 88. 9832...DESCRIPTION OF THE SEA SURFACE ................................................................... 2 The Wave Spectrum...Very Low Grazing Angles ......................................................................... 16 At HF and mm- Wave Frequencies

  4. Sea-level and deep-sea-temperature variability over the past 5.3 million years.

    PubMed

    Rohling, E J; Foster, G L; Grant, K M; Marino, G; Roberts, A P; Tamisiea, M E; Williams, F

    2014-04-24

    Ice volume (and hence sea level) and deep-sea temperature are key measures of global climate change. Sea level has been documented using several independent methods over the past 0.5 million years (Myr). Older periods, however, lack such independent validation; all existing records are related to deep-sea oxygen isotope (δ(18)O) data that are influenced by processes unrelated to sea level. For deep-sea temperature, only one continuous high-resolution (Mg/Ca-based) record exists, with related sea-level estimates, spanning the past 1.5 Myr. Here we present a novel sea-level reconstruction, with associated estimates of deep-sea temperature, which independently validates the previous 0-1.5 Myr reconstruction and extends it back to 5.3 Myr ago. We find that deep-sea temperature and sea level generally decreased through time, but distinctly out of synchrony, which is remarkable given the importance of ice-albedo feedbacks on the radiative forcing of climate. In particular, we observe a large temporal offset during the onset of Plio-Pleistocene ice ages, between a marked cooling step at 2.73 Myr ago and the first major glaciation at 2.15 Myr ago. Last, we tentatively infer that ice sheets may have grown largest during glacials with more modest reductions in deep-sea temperature.

  5. Generic comparison of protein inference engines.

    PubMed

    Claassen, Manfred; Reiter, Lukas; Hengartner, Michael O; Buhmann, Joachim M; Aebersold, Ruedi

    2012-04-01

    Protein identifications, instead of peptide-spectrum matches, constitute the biologically relevant result of shotgun proteomics studies. How to appropriately infer and report protein identifications has triggered a still ongoing debate. This debate has so far suffered from the lack of appropriate performance measures that allow us to objectively assess protein inference approaches. This study describes an intuitive, generic and yet formal performance measure and demonstrates how it enables experimentalists to select an optimal protein inference strategy for a given collection of fragment ion spectra. We applied the performance measure to systematically explore the benefit of excluding possibly unreliable protein identifications, such as single-hit wonders. Therefore, we defined a family of protein inference engines by extending a simple inference engine by thousands of pruning variants, each excluding a different specified set of possibly unreliable identifications. We benchmarked these protein inference engines on several data sets representing different proteomes and mass spectrometry platforms. Optimally performing inference engines retained all high confidence spectral evidence, without posterior exclusion of any type of protein identifications. Despite the diversity of studied data sets consistently supporting this rule, other data sets might behave differently. In order to ensure maximal reliable proteome coverage for data sets arising in other studies we advocate abstaining from rigid protein inference rules, such as exclusion of single-hit wonders, and instead consider several protein inference approaches and assess these with respect to the presented performance measure in the specific application context.

  6. Influence of sea ice on Arctic precipitation.

    PubMed

    Kopec, Ben G; Feng, Xiahong; Michel, Fred A; Posmentier, Eric S

    2016-01-05

    Global climate is influenced by the Arctic hydrologic cycle, which is, in part, regulated by sea ice through its control on evaporation and precipitation. However, the quantitative link between precipitation and sea ice extent is poorly constrained. Here we present observational evidence for the response of precipitation to sea ice reduction and assess the sensitivity of the response. Changes in the proportion of moisture sourced from the Arctic with sea ice change in the Canadian Arctic and Greenland Sea regions over the past two decades are inferred from annually averaged deuterium excess (d-excess) measurements from six sites. Other influences on the Arctic hydrologic cycle, such as the strength of meridional transport, are assessed using the North Atlantic Oscillation index. We find that the independent, direct effect of sea ice on the increase of the percentage of Arctic sourced moisture (or Arctic moisture proportion, AMP) is 18.2 ± 4.6% and 10.8 ± 3.6%/100,000 km(2) sea ice lost for each region, respectively, corresponding to increases of 10.9 ± 2.8% and 2.7 ± 1.1%/1 °C of warming in the vapor source regions. The moisture source changes likely result in increases of precipitation and changes in energy balance, creating significant uncertainty for climate predictions.

  7. Influence of sea ice on Arctic precipitation

    PubMed Central

    Kopec, Ben G.; Feng, Xiahong; Michel, Fred A.; Posmentier, Eric S.

    2016-01-01

    Global climate is influenced by the Arctic hydrologic cycle, which is, in part, regulated by sea ice through its control on evaporation and precipitation. However, the quantitative link between precipitation and sea ice extent is poorly constrained. Here we present observational evidence for the response of precipitation to sea ice reduction and assess the sensitivity of the response. Changes in the proportion of moisture sourced from the Arctic with sea ice change in the Canadian Arctic and Greenland Sea regions over the past two decades are inferred from annually averaged deuterium excess (d-excess) measurements from six sites. Other influences on the Arctic hydrologic cycle, such as the strength of meridional transport, are assessed using the North Atlantic Oscillation index. We find that the independent, direct effect of sea ice on the increase of the percentage of Arctic sourced moisture (or Arctic moisture proportion, AMP) is 18.2 ± 4.6% and 10.8 ± 3.6%/100,000 km2 sea ice lost for each region, respectively, corresponding to increases of 10.9 ± 2.8% and 2.7 ± 1.1%/1 °C of warming in the vapor source regions. The moisture source changes likely result in increases of precipitation and changes in energy balance, creating significant uncertainty for climate predictions. PMID:26699509

  8. The SeaWinds Scatterometer Instrument

    NASA Technical Reports Server (NTRS)

    Wu, C.; Graf, J.; Freilich, M.; Long, D.; Spencer, M.; Tsai, W.; Lisman, D.; Winn, C.

    1994-01-01

    The SeaWinds scatterometer instrument is currently being developed by NASA/JPL, as part of the NASA EOS Program, for flight on the Hapanese ADEOS II mission in 1999. This Ku-band radar scatterometer will infer surface wind speed and direction by measuring the radar normalized backscatter cross-section over several different azimuth angles. This paper presents the design characteristics of and operational approach to the instrument itself.

  9. From Sea to Shining Sea

    ERIC Educational Resources Information Center

    Scott, Beverly

    2005-01-01

    Deep down in the depths of the sea, beautiful fish, mysterious ocean life, and unusual plants glimmer and glow in the eerie atmosphere of an ever-changing ocean. This article describes how, with this vision and a purpose in mind, three teachers pulled open classroom walls and joined forces so their second graders could create a mammoth 30 x 75"…

  10. Protein inference: A protein quantification perspective.

    PubMed

    He, Zengyou; Huang, Ting; Liu, Xiaoqing; Zhu, Peijun; Teng, Ben; Deng, Shengchun

    2016-08-01

    In mass spectrometry-based shotgun proteomics, protein quantification and protein identification are two major computational problems. To quantify the protein abundance, a list of proteins must be firstly inferred from the raw data. Then the relative or absolute protein abundance is estimated with quantification methods, such as spectral counting. Until now, most researchers have been dealing with these two processes separately. In fact, the protein inference problem can be regarded as a special protein quantification problem in the sense that truly present proteins are those proteins whose abundance values are not zero. Some recent published papers have conceptually discussed this possibility. However, there is still a lack of rigorous experimental studies to test this hypothesis. In this paper, we investigate the feasibility of using protein quantification methods to solve the protein inference problem. Protein inference methods aim to determine whether each candidate protein is present in the sample or not. Protein quantification methods estimate the abundance value of each inferred protein. Naturally, the abundance value of an absent protein should be zero. Thus, we argue that the protein inference problem can be viewed as a special protein quantification problem in which one protein is considered to be present if its abundance is not zero. Based on this idea, our paper tries to use three simple protein quantification methods to solve the protein inference problem effectively. The experimental results on six data sets show that these three methods are competitive with previous protein inference algorithms. This demonstrates that it is plausible to model the protein inference problem as a special protein quantification task, which opens the door of devising more effective protein inference algorithms from a quantification perspective. The source codes of our methods are available at: http://code.google.com/p/protein-inference/.

  11. Radioactivity concentrations in mussel (Mytilus galloprovincialis) of Turkish Sea coast and contribution of ²¹⁰Po to the radiation dose.

    PubMed

    Kılıç, Önder; Belivermiş, Murat; Cotuk, Yavuz; Topçuoğlu, Sayhan

    2014-03-15

    Radionuclides levels were determined in indigenous and transplanted mussels (Mytilus galloprovincialis) collected from Turkish marine environment. Radioactivity concentrations of ¹³⁷Cs, ⁴⁰K, ²²⁶Ra, ²²⁸Ra, ²¹⁰Po and ²¹⁰Pb were determined in the soft tissues of the mussel samples collected in Bosphorus Strait, Coasts of Black Sea, Marmara Sea and Aegean Sea. Mussel transplantation was carried out by using mussel cages in Levantine Sea coast since M. galloprovincialis did not naturally adapt along the coast. The average activity concentrations of ¹³⁷Cs, ⁴⁰K, ²²⁶Ra, ²²⁸Ra, ²¹⁰Po and ²¹⁰Pb in the coastline of Turkey were found to be 0.7±0.1, 469±24, 0.9±0.1, 1.0±0.1, 122±4 and 10.9±0.9 Bq kg⁻¹ in dry weight (dw), respectively. The average of ²¹⁰Po/²¹⁰Pb ratio was found to be ∼14. Total annual effective ²¹⁰Po dose was calculated to be in the range of 0.25-3.30 μSv due to mussel consumption. Radioactivity and dose levels were compared with those of similar studies carried out in Mediterranean countries.

  12. A Comparison of Two Student Instructional Rating Forms Utilizing High-Inference Versus Moderate Inference Items.

    ERIC Educational Resources Information Center

    Wilson, Pamela W.

    Two types of items used in student evaluations of college teaching were compared: high-inference items, which require considerable inferring from what is seen or heard in the classroom to labelling of teacher behavior; and moderate-inference items, such as "teacher listens carefully." Two instruments were administered to random halves of…

  13. High resolution archives from the Black Sea and Caspian Sea as records of hydrological changes during the Holocene

    NASA Astrophysics Data System (ADS)

    Marret, F.; Mudie, P.; Leroy, S.; Aksu, A.; Hiscott, R.

    2009-04-01

    the occurrence of major changes in the Black Sea surface conditions. The dinocyst data have also been integrated in a multiple-proxy study carried out on this record, including carbon and sulphur isotopes, ostracodes and pollen studies. The record, starting at around 9.3 ka BP documents a mild, humid climate and brackish water environment, with the dominance of the quasi-endemic association Spiniferites cruciformis-Pyxidinopsis psilata. A few occurrences of Mediterranean species and recent ecological information from Caspian Sea dinocysts indicate that salinity was not below 7. This brackish association lasted until 6.0 ka BP when it was completely replaced by euryhaline species. However, a significant presence of euryhaline species at 8.5 ka BP indicates that marine conditions were being established, i.e. that the Black Sea was even then connected to the Marmara Sea via the Bosphorus Strait. The period between the first significant increase of euryhaline taxa and the disappearance of the brackish species is characterised by the occurrence of specimens with strong morphological variability. This implies that changes in the sea surface conditions were probably gradual, and that the Black Sea reached its present conditions in about 1500 years. We will also present changes in salinity in the Caspian Sea for the last 5500 years based on dinocyst records. References 1- Marret F., Mudie P.J., Aksu A. and Hiscott R.N. (2007) Holocene dinocyst record of a two-step transformation of the Neoeuxinian brackish water lake into the Black Sea. Quaternary International. 2- Marret F., Leroy S., Chalié F. and Gasse F. (2004) New organic-walled dinoflagellate cysts from recent sediments of Central Asian Seas. . Review of Paleobotany and Palynology 129, 1-20. 3- Leroy S A G, Marret F, Gibert E, Chalie F, Reyss J L and Arpe K (2007) River inflow and salinity changes in the Caspian Sea during the last 5500 years. Quaternary Science Reviews vol 26 issue 25-28 pp 3359-3383

  14. Forward and Backward Inference in Spatial Cognition

    PubMed Central

    Penny, Will D.; Zeidman, Peter; Burgess, Neil

    2013-01-01

    This paper shows that the various computations underlying spatial cognition can be implemented using statistical inference in a single probabilistic model. Inference is implemented using a common set of ‘lower-level’ computations involving forward and backward inference over time. For example, to estimate where you are in a known environment, forward inference is used to optimally combine location estimates from path integration with those from sensory input. To decide which way to turn to reach a goal, forward inference is used to compute the likelihood of reaching that goal under each option. To work out which environment you are in, forward inference is used to compute the likelihood of sensory observations under the different hypotheses. For reaching sensory goals that require a chaining together of decisions, forward inference can be used to compute a state trajectory that will lead to that goal, and backward inference to refine the route and estimate control signals that produce the required trajectory. We propose that these computations are reflected in recent findings of pattern replay in the mammalian brain. Specifically, that theta sequences reflect decision making, theta flickering reflects model selection, and remote replay reflects route and motor planning. We also propose a mapping of the above computational processes onto lateral and medial entorhinal cortex and hippocampus. PMID:24348230

  15. Application of Transformations in Parametric Inference

    ERIC Educational Resources Information Center

    Brownstein, Naomi; Pensky, Marianna

    2008-01-01

    The objective of the present paper is to provide a simple approach to statistical inference using the method of transformations of variables. We demonstrate performance of this powerful tool on examples of constructions of various estimation procedures, hypothesis testing, Bayes analysis and statistical inference for the stress-strength systems.…

  16. Scalar Inferences in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Chevallier, Coralie; Wilson, Deirdre; Happe, Francesca; Noveck, Ira

    2010-01-01

    On being told "John or Mary will come", one might infer that "not both" of them will come. Yet the semantics of "or" is compatible with a situation where both John and Mary come. Inferences of this type, which enrich the semantics of "or" from an "inclusive" to an "exclusive" interpretation, have been extensively studied in linguistic pragmatics.…

  17. The Reasoning behind Informal Statistical Inference

    ERIC Educational Resources Information Center

    Makar, Katie; Bakker, Arthur; Ben-Zvi, Dani

    2011-01-01

    Informal statistical inference (ISI) has been a frequent focus of recent research in statistics education. Considering the role that context plays in developing ISI calls into question the need to be more explicit about the reasoning that underpins ISI. This paper uses educational literature on informal statistical inference and philosophical…

  18. Local and Global Thinking in Statistical Inference

    ERIC Educational Resources Information Center

    Pratt, Dave; Johnston-Wilder, Peter; Ainley, Janet; Mason, John

    2008-01-01

    In this reflective paper, we explore students' local and global thinking about informal statistical inference through our observations of 10- to 11-year-olds, challenged to infer the unknown configuration of a virtual die, but able to use the die to generate as much data as they felt necessary. We report how they tended to focus on local changes…

  19. Forward and backward inference in spatial cognition.

    PubMed

    Penny, Will D; Zeidman, Peter; Burgess, Neil

    2013-01-01

    This paper shows that the various computations underlying spatial cognition can be implemented using statistical inference in a single probabilistic model. Inference is implemented using a common set of 'lower-level' computations involving forward and backward inference over time. For example, to estimate where you are in a known environment, forward inference is used to optimally combine location estimates from path integration with those from sensory input. To decide which way to turn to reach a goal, forward inference is used to compute the likelihood of reaching that goal under each option. To work out which environment you are in, forward inference is used to compute the likelihood of sensory observations under the different hypotheses. For reaching sensory goals that require a chaining together of decisions, forward inference can be used to compute a state trajectory that will lead to that goal, and backward inference to refine the route and estimate control signals that produce the required trajectory. We propose that these computations are reflected in recent findings of pattern replay in the mammalian brain. Specifically, that theta sequences reflect decision making, theta flickering reflects model selection, and remote replay reflects route and motor planning. We also propose a mapping of the above computational processes onto lateral and medial entorhinal cortex and hippocampus.

  20. Inferring Learners' Knowledge from Their Actions

    ERIC Educational Resources Information Center

    Rafferty, Anna N.; LaMar, Michelle M.; Griffiths, Thomas L.

    2015-01-01

    Watching another person take actions to complete a goal and making inferences about that person's knowledge is a relatively natural task for people. This ability can be especially important in educational settings, where the inferences can be used for assessment, diagnosing misconceptions, and providing informative feedback. In this paper, we…

  1. Symbolic transfer entropy: inferring directionality in biosignals.

    PubMed

    Staniek, Matthäus; Lehnertz, Klaus

    2009-12-01

    Inferring directional interactions from biosignals is of crucial importance to improve understanding of dynamical interdependences underlying various physiological and pathophysiological conditions. We here present symbolic transfer entropy as a robust measure to infer the direction of interactions between multidimensional dynamical systems. We demonstrate its performance in quantifying driver-responder relationships in a network of coupled nonlinear oscillators and in the human epileptic brain.

  2. Predictive Inferences are Represented as Hypothetical Facts

    ERIC Educational Resources Information Center

    Campion, Nicolas

    2004-01-01

    Three experiments examined the processing of predictive and deductive inferences elicited by narrative texts. In Experiment 1, lexical decision responses indicated that these inferences were activated during reading. In Experiment 2, sentences expressing that an event had ''maybe'' taken place were shown to be appropriate in verifying predictive…

  3. Causal Inferences during Text Comprehension and Production.

    ERIC Educational Resources Information Center

    Kemper, Susan

    As comprehension failure results whenever readers are unable to infer missing causal connections, recent comprehension research has focused both on assessing the inferential complexity of texts and on investigating students' developing ability to infer causal relationships. Studies have demonstrated that texts rely on four types of causal…

  4. Measuring the Inference Load of a Text.

    ERIC Educational Resources Information Center

    Kemper, Susan

    1983-01-01

    A new approach to measuring readability is proposed based on the analysis of texts as causally connected chains of actions, physical states, and mental states. Using the inference load formula reflecting the difficulty readers have in inferring causal connections, the difficulty of texts can be adjusted for readers differing in skill or knowledge.…

  5. Causal inference in economics and marketing.

    PubMed

    Varian, Hal R

    2016-07-05

    This is an elementary introduction to causal inference in economics written for readers familiar with machine learning methods. The critical step in any causal analysis is estimating the counterfactual-a prediction of what would have happened in the absence of the treatment. The powerful techniques used in machine learning may be useful for developing better estimates of the counterfactual, potentially improving causal inference.

  6. The Impact of Disablers on Predictive Inference

    ERIC Educational Resources Information Center

    Cummins, Denise Dellarosa

    2014-01-01

    People consider alternative causes when deciding whether a cause is responsible for an effect (diagnostic inference) but appear to neglect them when deciding whether an effect will occur (predictive inference). Five experiments were conducted to test a 2-part explanation of this phenomenon: namely, (a) that people interpret standard predictive…

  7. Genetic Network Inference Using Hierarchical Structure

    PubMed Central

    Kimura, Shuhei; Tokuhisa, Masato; Okada-Hatakeyama, Mariko

    2016-01-01

    Many methods for inferring genetic networks have been proposed, but the regulations they infer often include false-positives. Several researchers have attempted to reduce these erroneous regulations by proposing the use of a priori knowledge about the properties of genetic networks such as their sparseness, scale-free structure, and so on. This study focuses on another piece of a priori knowledge, namely, that biochemical networks exhibit hierarchical structures. Based on this idea, we propose an inference approach that uses the hierarchical structure in a target genetic network. To obtain a reasonable hierarchical structure, the first step of the proposed approach is to infer multiple genetic networks from the observed gene expression data. We take this step using an existing method that combines a genetic network inference method with a bootstrap method. The next step is to extract a hierarchical structure from the inferred networks that is consistent with most of the networks. Third, we use the hierarchical structure obtained to assign confidence values to all candidate regulations. Numerical experiments are also performed to demonstrate the effectiveness of using the hierarchical structure in the genetic network inference. The improvement accomplished by the use of the hierarchical structure is small. However, the hierarchical structure could be used to improve the performances of many existing inference methods. PMID:26941653

  8. Utilizing Statistical Inference to Guide Expectations and Test Structuring During Operational Testing and Evaluation

    DTIC Science & Technology

    2011-04-30

    Commander, Naval Sea Systems Command • Army Contracting Command, U.S. Army Materiel Command • Program Manager, Airborne, Maritime and Fixed Station...are in the area of the Design and Acquisition of Military Assets. Specific domains of interests include the concept of value and its integration...inference may point to areas where the test may be modified or additional control measures may be introduced to increase the likelihood of obtaining

  9. Saturn's ionosphere - Inferred electron densities

    NASA Astrophysics Data System (ADS)

    Kaiser, M. L.; Desch, M. D.; Connerney, J. E. P.

    1984-04-01

    During the two Voyager encounters with Saturn, radio bursts were detected which appear to have originated from atmospheric lightning storms. Although these bursts generally extended over frequencies from as low as 100 kHz to the upper detection limit of the instrument, 40 MHz, they often exhibited a sharp but variable low frequency cutoff below which bursts were not detected. We interpret the variable low-frequency extent of these bursts to be due to the reflection of the radio waves as they propagate through an ionosphere which varies with local time. We obtain estimates of electron densities at a variety of latitude and local time locations. These compare well with the dawn and dusk densities measured by the Pioneer 11 Voyager Radio Science investigations, and with model predictions for dayside densities. However, we infer a two-order-of-magnitude diurnal variation of electron density, which had not been anticipated by theoretical models of Saturn's ionosphere, and an equally dramatic extinction of ionospheric electron density by Saturn's rings. Previously announced in STAR as N84-17102

  10. Active Inference: A Process Theory.

    PubMed

    Friston, Karl; FitzGerald, Thomas; Rigoli, Francesco; Schwartenbeck, Philipp; Pezzulo, Giovanni

    2017-01-01

    This article describes a process theory based on active inference and belief propagation. Starting from the premise that all neuronal processing (and action selection) can be explained by maximizing Bayesian model evidence-or minimizing variational free energy-we ask whether neuronal responses can be described as a gradient descent on variational free energy. Using a standard (Markov decision process) generative model, we derive the neuronal dynamics implicit in this description and reproduce a remarkable range of well-characterized neuronal phenomena. These include repetition suppression, mismatch negativity, violation responses, place-cell activity, phase precession, theta sequences, theta-gamma coupling, evidence accumulation, race-to-bound dynamics, and transfer of dopamine responses. Furthermore, the (approximately Bayes' optimal) behavior prescribed by these dynamics has a degree of face validity, providing a formal explanation for reward seeking, context learning, and epistemic foraging. Technically, the fact that a gradient descent appears to be a valid description of neuronal activity means that variational free energy is a Lyapunov function for neuronal dynamics, which therefore conform to Hamilton's principle of least action.

  11. Reinforcement learning or active inference?

    PubMed

    Friston, Karl J; Daunizeau, Jean; Kiebel, Stefan J

    2009-07-29

    This paper questions the need for reinforcement learning or control theory when optimising behaviour. We show that it is fairly simple to teach an agent complicated and adaptive behaviours using a free-energy formulation of perception. In this formulation, agents adjust their internal states and sampling of the environment to minimize their free-energy. Such agents learn causal structure in the environment and sample it in an adaptive and self-supervised fashion. This results in behavioural policies that reproduce those optimised by reinforcement learning and dynamic programming. Critically, we do not need to invoke the notion of reward, value or utility. We illustrate these points by solving a benchmark problem in dynamic programming; namely the mountain-car problem, using active perception or inference under the free-energy principle. The ensuing proof-of-concept may be important because the free-energy formulation furnishes a unified account of both action and perception and may speak to a reappraisal of the role of dopamine in the brain.

  12. Reinforcement Learning or Active Inference?

    PubMed Central

    Friston, Karl J.; Daunizeau, Jean; Kiebel, Stefan J.

    2009-01-01

    This paper questions the need for reinforcement learning or control theory when optimising behaviour. We show that it is fairly simple to teach an agent complicated and adaptive behaviours using a free-energy formulation of perception. In this formulation, agents adjust their internal states and sampling of the environment to minimize their free-energy. Such agents learn causal structure in the environment and sample it in an adaptive and self-supervised fashion. This results in behavioural policies that reproduce those optimised by reinforcement learning and dynamic programming. Critically, we do not need to invoke the notion of reward, value or utility. We illustrate these points by solving a benchmark problem in dynamic programming; namely the mountain-car problem, using active perception or inference under the free-energy principle. The ensuing proof-of-concept may be important because the free-energy formulation furnishes a unified account of both action and perception and may speak to a reappraisal of the role of dopamine in the brain. PMID:19641614

  13. Saturn's ionosphere: Inferred electron densities

    NASA Technical Reports Server (NTRS)

    Kaiser, M. L.; Desch, M. D.; Connerney, J. E. P.

    1983-01-01

    During the two Voyager encounters with Saturn, radio bursts were detected which appear to have originated from atmospheric lightning storms. Although these bursts generally extended over frequencies from as low as 100 kHz to the upper detection limit of the instrument, 40 MHz, they often exhibited a sharp but variable low frequency cutoff below which bursts were not detected. We interpret the variable low-frequency extent of these bursts to be due to the reflection of the radio waves as they propagate through an ionosphere which varies with local time. We obtain estimates of electron densities at a variety of latitude and local time locations. These compare well with the dawn and dusk densitis measured by the Pioneer 11 Voyager Radio Science investigations, and with model predictions for dayside densities. However, we infer a two-order-of-magnitude diurnal variation of electron density, which had not been anticipated by theoretical models of Saturn's ionosphere, and an equally dramatic extinction of ionospheric electron density by Saturn's rings.

  14. Redshift data and statistical inference

    NASA Technical Reports Server (NTRS)

    Newman, William I.; Haynes, Martha P.; Terzian, Yervant

    1994-01-01

    Frequency histograms and the 'power spectrum analysis' (PSA) method, the latter developed by Yu & Peebles (1969), have been widely employed as techniques for establishing the existence of periodicities. We provide a formal analysis of these two classes of methods, including controlled numerical experiments, to better understand their proper use and application. In particular, we note that typical published applications of frequency histograms commonly employ far greater numbers of class intervals or bins than is advisable by statistical theory sometimes giving rise to the appearance of spurious patterns. The PSA method generates a sequence of random numbers from observational data which, it is claimed, is exponentially distributed with unit mean and variance, essentially independent of the distribution of the original data. We show that the derived random processes is nonstationary and produces a small but systematic bias in the usual estimate of the mean and variance. Although the derived variable may be reasonably described by an exponential distribution, the tail of the distribution is far removed from that of an exponential, thereby rendering statistical inference and confidence testing based on the tail of the distribution completely unreliable. Finally, we examine a number of astronomical examples wherein these methods have been used giving rise to widespread acceptance of statistically unconfirmed conclusions.

  15. Causal Inference in Public Health

    PubMed Central

    Glass, Thomas A.; Goodman, Steven N.; Hernán, Miguel A.; Samet, Jonathan M.

    2014-01-01

    Causal inference has a central role in public health; the determination that an association is causal indicates the possibility for intervention. We review and comment on the long-used guidelines for interpreting evidence as supporting a causal association and contrast them with the potential outcomes framework that encourages thinking in terms of causes that are interventions. We argue that in public health this framework is more suitable, providing an estimate of an action’s consequences rather than the less precise notion of a risk factor’s causal effect. A variety of modern statistical methods adopt this approach. When an intervention cannot be specified, causal relations can still exist, but how to intervene to change the outcome will be unclear. In application, the often-complex structure of causal processes needs to be acknowledged and appropriate data collected to study them. These newer approaches need to be brought to bear on the increasingly complex public health challenges of our globalized world. PMID:23297653

  16. Three Roads Diverged? Routes To Phylogeographic Inference

    PubMed Central

    Bloomquist, Erik W.; Lemey, Philippe

    2010-01-01

    Phylogeographic methods enable inference of the geographical history of genetic lineages. Recent examples successfully explore the patterns of human migration and the origins and spread of viral pandemics. Nevertheless, longstanding disagreement exists over the use and validity of certain phylogeographic inference methodologies. In this paper, we highlight three distinct frameworks for phylogeographic inference to give a taste of this disagreement. Each of the three approaches presents a different viewpoint on phylogeography, most fundamentally how we view the relationship between the inferred history of the sample and the history of the population the sample is embedded in. Satisfactory resolution of this relationship between history of the tree and history of the population remains a challenge for all but the most trivial models of phylogeographic processes. Intriguingly, we believe that some recent methods that entirely side-step inference about the history of the population will eventually help the field toward this goal. PMID:20863591

  17. Inference-based constraint satisfaction supports explanation

    SciTech Connect

    Sqalli, M.H.; Freuder, E.C.

    1996-12-31

    Constraint satisfaction problems are typically solved using search, augmented by general purpose consistency inference methods. This paper proposes a paradigm shift in which inference is used as the primary problem solving method, and attention is focused on special purpose, domain specific inference methods. While we expect this approach to have computational advantages, we emphasize here the advantages of a solution method that is more congenial to human thought processes. Specifically we use inference-based constraint satisfaction to support explanations of the problem solving behavior that are considerably more meaningful than a trace of a search process would be. Logic puzzles are used as a case study. Inference-based constraint satisfaction proves surprisingly powerful and easily extensible in this domain. Problems drawn from commercial logic puzzle booklets are used for evaluation. Explanations are produced that compare well with the explanations provided by these booklets.

  18. Inference of mantle viscosity for depth resolutions of GIA observations

    NASA Astrophysics Data System (ADS)

    Nakada, Masao; Okuno, Jun'ichi

    2016-11-01

    Inference of the mantle viscosity from observations for glacial isostatic adjustment (GIA) process has usually been conducted through the analyses based on the simple three-layer viscosity model characterized by lithospheric thickness, upper- and lower-mantle viscosities. Here, we examine the viscosity structures for the simple three-layer viscosity model and also for the two-layer lower-mantle viscosity model defined by viscosities of η670,D (670-D km depth) and ηD,2891 (D-2891 km depth) with D-values of 1191, 1691 and 2191 km. The upper-mantle rheological parameters for the two-layer lower-mantle viscosity model are the same as those for the simple three-layer one. For the simple three-layer viscosity model, rate of change of degree-two zonal harmonics of geopotential due to GIA process (GIA-induced J˙2) of -(6.0-6.5) × 10-11 yr-1 provides two permissible viscosity solutions for the lower mantle, (7-20) × 1021 and (5-9) × 1022 Pa s, and the analyses with observational constraints of the J˙2 and Last Glacial Maximum (LGM) sea levels at Barbados and Bonaparte Gulf indicate (5-9) × 1022 Pa s for the lower mantle. However, the analyses for the J˙2 based on the two-layer lower-mantle viscosity model only require a viscosity layer higher than (5-10) × 1021 Pa s for a depth above the core-mantle boundary (CMB), in which the value of (5-10) × 1021 Pa s corresponds to the solution of (7-20) × 1021 Pa s for the simple three-layer one. Moreover, the analyses with the J˙2 and LGM sea level constraints for the two-layer lower-mantle viscosity model indicate two viscosity solutions: η670,1191 > 3 × 1021 and η1191,2891 ˜ (5-10) × 1022 Pa s, and η670,1691 > 1022 and η1691,2891 ˜ (5-10) × 1022 Pa s. The inferred upper-mantle viscosity for such solutions is (1-4) × 1020 Pa s similar to the estimate for the simple three-layer viscosity model. That is, these analyses require a high viscosity layer of (5-10) × 1022 Pa s at least in the deep mantle, and suggest

  19. Microseisms and sea wave height in the Ligurian Sea: a preliminary analysis.

    NASA Astrophysics Data System (ADS)

    Zunino, A.; Ferretti, G.; Scafidi, D.; Barani, S.; Pasta, M.; Spallarossa, D.

    2012-04-01

    Analysis of the relationship between microseisms and sea wave heights is a fundamental step for understanding the interaction of sea storms with near coastal environment, as well as to gain insights about the possibility of forecasting sea wave heights from microseism. The possibility to predict sea wave heights in the Ligurian Sea is analyzed in this study using about a month of observations from both seismic recordings from a near-coast station (IMI - Imperia Monte Faudo) and significant sea wave heights measured from a buoy (Côte d'Azur buoy, Météo-France network). We focus on the analysis of the vertical component of microseism, which reveals a strong correlation with measured sea wave heights. Looking at the amplitude spectrogram of the vertical component of microseism, we recognize the effects of several meteo-marine events that can be ascribed to Atlantic barometric pressure lows and a series of sea storms in the Ligurian Sea. Moreover, the distinction between primary and secondary microseism is inferred from the spectrogram, even if, because of the superposition of Atlantic and Ligurian effects, it sometimes results difficult. Analysis of microseism polarization reveals a double origin which determines two prevailing orientations, corresponding to Atlantic and Ligurian meteo-marine phenomena. We feature the spectral properties of microseism making a close correlation among (1) the power spectral density spectrum of microseism, (2) the significant sea wave heights measured from the buoy and (3) sea storms occurred in the period under study, showing that there is a good correlation between spectral energy content of microseism and sea wave height. Finally, in order to set up a predictive law, we solve an inverse problem to find the optimal parameters that allow us to estimate the sea wave height given the vertical component of microseism. Specifically, the application of the definition of significant height wave height for the microseism needs the

  20. Causal inference in obesity research.

    PubMed

    Franks, P W; Atabaki-Pasdar, N

    2017-03-01

    Obesity is a risk factor for a plethora of severe morbidities and premature death. Most supporting evidence comes from observational studies that are prone to chance, bias and confounding. Even data on the protective effects of weight loss from randomized controlled trials will be susceptible to confounding and bias if treatment assignment cannot be masked, which is usually the case with lifestyle and surgical interventions. Thus, whilst obesity is widely considered the major modifiable risk factor for many chronic diseases, its causes and consequences are often difficult to determine. Addressing this is important, as the prevention and treatment of any disease requires that interventions focus on causal risk factors. Disease prediction, although not dependent on knowing the causes, is nevertheless enhanced by such knowledge. Here, we provide an overview of some of the barriers to causal inference in obesity research and discuss analytical approaches, such as Mendelian randomization, that can help to overcome these obstacles. In a systematic review of the literature in this field, we found: (i) probable causal relationships between adiposity and bone health/disease, cancers (colorectal, lung and kidney cancers), cardiometabolic traits (blood pressure, fasting insulin, inflammatory markers and lipids), uric acid concentrations, coronary heart disease and venous thrombosis (in the presence of pulmonary embolism), (ii) possible causal relationships between adiposity and gray matter volume, depression and common mental disorders, oesophageal cancer, macroalbuminuria, end-stage renal disease, diabetic kidney disease, nuclear cataract and gall stone disease, and (iii) no evidence for causal relationships between adiposity and Alzheimer's disease, pancreatic cancer, venous thrombosis (in the absence of pulmonary embolism), liver function and periodontitis.

  1. Inferring Mantle From Basalt Composition

    NASA Astrophysics Data System (ADS)

    Stracke, A.

    2014-12-01

    Isotope ratios in oceanic basalts, first reported by Gast and co-workers 50 years ago, are unique tracers of mantle composition, because they are expected to mirror the composition of their mantle sources. While the latter is certainly true for homogeneous sources, the plethora of studies over the last 50 years have shown that mantle sources are isotopically heterogeneous on different length scales. Isotopic differences exist between basalts from different ocean basins, volcanoes of individual ocean islands, lava flows of a single volcano, and even in μm sized melt inclusions in a single mineral grain. Diffusion, which acts to homogenize isotopic heterogeneity over Gyr timescales, limits the length scale of isotopic heterogeneity in the mantle to anywhere between several mm to 10s of meters. Melting regions, however, are typically several 100 km wide and up to 100 km deep. The scale of melting is thus generally orders of magnitude larger than the scale of isotopic heterogeneity. How partial melts mix during melting, melt transport, and melt storage then inevitably influences how isotopic heterogeneity is conveyed from source to melt. The isotopic composition of oceanic basalts hence provides an integrated signal of isotopically diverse melts. Recent mixing models and observed isotopic differences between source (abyssal peridotites) and melts (MORB) show that the range of isotopic heterogeneity of erupted melts need NOT directly reflect that of their source(s), nor need observed isotopic endmembers in source and melts be congruent. Many geochemical models, however, implicitly assume equivalence of source and melt composition. Especially when attempting to infer spatial patterns of isotopic heterogeneity in the mantle from those observed in erupted melts, or for linking isotopic diversity to geophysical structures in the mantle requires a more profound understanding to what extent erupted melts represent the isotopic composition of their mantle sources.

  2. Inferring genetic networks from microarray data.

    SciTech Connect

    May, Elebeoba Eni; Davidson, George S.; Martin, Shawn Bryan; Werner-Washburne, Margaret C.; Faulon, Jean-Loup Michel

    2004-06-01

    In theory, it should be possible to infer realistic genetic networks from time series microarray data. In practice, however, network discovery has proved problematic. The three major challenges are: (1) inferring the network; (2) estimating the stability of the inferred network; and (3) making the network visually accessible to the user. Here we describe a method, tested on publicly available time series microarray data, which addresses these concerns. The inference of genetic networks from genome-wide experimental data is an important biological problem which has received much attention. Approaches to this problem have typically included application of clustering algorithms [6]; the use of Boolean networks [12, 1, 10]; the use of Bayesian networks [8, 11]; and the use of continuous models [21, 14, 19]. Overviews of the problem and general approaches to network inference can be found in [4, 3]. Our approach to network inference is similar to earlier methods in that we use both clustering and Boolean network inference. However, we have attempted to extend the process to better serve the end-user, the biologist. In particular, we have incorporated a system to assess the reliability of our network, and we have developed tools which allow interactive visualization of the proposed network.

  3. Statistical Physics of High Dimensional Inference

    NASA Astrophysics Data System (ADS)

    Advani, Madhu; Ganguli, Surya

    To model modern large-scale datasets, we need efficient algorithms to infer a set of P unknown model parameters from N noisy measurements. What are fundamental limits on the accuracy of parameter inference, given limited measurements, signal-to-noise ratios, prior information, and computational tractability requirements? How can we combine prior information with measurements to achieve these limits? Classical statistics gives incisive answers to these questions as the measurement density α =N/P --> ∞ . However, modern high-dimensional inference problems, in fields ranging from bio-informatics to economics, occur at finite α. We formulate and analyze high-dimensional inference analytically by applying the replica and cavity methods of statistical physics where data serves as quenched disorder and inferred parameters play the role of thermal degrees of freedom. Our analysis reveals that widely cherished Bayesian inference algorithms such as maximum likelihood and maximum a posteriori are suboptimal in the modern setting, and yields new tractable, optimal algorithms to replace them as well as novel bounds on the achievable accuracy of a large class of high-dimensional inference algorithms. Thanks to Stanford Graduate Fellowship and Mind Brain Computation IGERT grant for support.

  4. On Bayesian Inductive Inference & Predictive Estimation

    NASA Technical Reports Server (NTRS)

    Cheeseman, Peter; Stutz, John; Smelyanskiy, Vadim

    2004-01-01

    We investigate Bayesian inference and the Principle of Maximum Entropy (PME) as methods for doing inference under uncertainty. This investigation is primarily through concrete examples that have been previously investigated in the literature. We find that it is possible to do Bayesian inference and PME inference using the same information, despite claims to the contrary, but that the results are not directly comparable. This is because Bayesian inference yields a probability density function (pdf) over the unknown model parameters, whereas PME yields point estimates. If mean estimates are extracted from the Bayesian pdfs, the resulting parameter estimates can differ radically from the PME values and also from the Maximum Likelihood values. We conclude that these differences are due to the Bayesian inference not assuming anything beyond the given prior probabilities and the data, whereas PME implicitly assumes that the given constraints are the only constraints that are operating. Since this assumption can be wrong, PME values may have to be revised when subsequent data shows evidence for more constraints. The entropy concentration previously "proved" by E. T. Jaynes is shown to be in error. Further, we show that PME is a generalized form of independence assumption, and so can be a very powerful method of inference when the variables being investigated are largely independent of each other.

  5. Linguistic Markers of Inference Generation While Reading.

    PubMed

    Clinton, Virginia; Carlson, Sarah E; Seipel, Ben

    2016-06-01

    Words can be informative linguistic markers of psychological constructs. The purpose of this study is to examine associations between word use and the process of making meaningful connections to a text while reading (i.e., inference generation). To achieve this purpose, think-aloud data from third-fifth grade students ([Formula: see text]) reading narrative texts were hand-coded for inferences. These data were also processed with a computer text analysis tool, Linguistic Inquiry and Word Count, for percentages of word use in the following categories: cognitive mechanism words, nonfluencies, and nine types of function words. Findings indicate that cognitive mechanisms were an independent, positive predictor of connections to background knowledge (i.e., elaborative inference generation) and nonfluencies were an independent, negative predictor of connections within the text (i.e., bridging inference generation). Function words did not provide unique variance towards predicting inference generation. These findings are discussed in the context of a cognitive reflection model and the differences between bridging and elaborative inference generation. In addition, potential practical implications for intelligent tutoring systems and computer-based methods of inference identification are presented.

  6. Inference and the introductory statistics course

    NASA Astrophysics Data System (ADS)

    Pfannkuch, Maxine; Regan, Matt; Wild, Chris; Budgett, Stephanie; Forbes, Sharleen; Harraway, John; Parsonage, Ross

    2011-10-01

    This article sets out some of the rationale and arguments for making major changes to the teaching and learning of statistical inference in introductory courses at our universities by changing from a norm-based, mathematical approach to more conceptually accessible computer-based approaches. The core problem of the inferential argument with its hypothetical probabilistic reasoning process is examined in some depth. We argue that the revolution in the teaching of inference must begin. We also discuss some perplexing issues, problematic areas and some new insights into language conundrums associated with introducing the logic of inference through randomization methods.

  7. Geochemistry of the Black Sea during the last 15 kyr: A protracted evolution of its hydrography and ecology

    USGS Publications Warehouse

    Piper, David Z.

    2016-01-01

    The Black Sea is a 2200 m deep anoxic, marine sea connected to the Mediterranean Sea via the Dardanelles Strait, Marmara Sea, and the 3 km wide, 35 m deep Bosphorus Strait. The biogeochemistry of sediment from the Anatolia slope has recorded changes to the hydrography leading up to and following the input of Mediterranean water at ~9.4 ka (103 years B.P.), when global sea level rose to the level of the Bosphorus sill and high-salinity water from the Mediterranean began to spill into the then brackish lake. The water initially mixed little with the lake water but cascaded to the bottom where it remained essentially isolated for ~1.6 kyr, the time required to fill the basin from the bottom up at its present input rate. The accumulation of Mo in the seafloor sediments, a proxy of bottom-water anoxia, increased sharply at ~8.6 ka, when bacterial respiration in the bottom water advanced to SO42− reduction by the oxidation of organic detritus that settled out of the photic zone. Its accumulation remained elevated to ~5.6 ka, when it decreased 60%, only to again increase slightly at ~2.0 ka. The accumulation of Corg, a proxy of primary productivity, increased threefold to fourfold at ~7.8 ka, when upward mixing of the high-salinity bottom water replaced the then thin veneer of the brackish photic zone in less than 50 years. From that time onward, the accumulation of Corg, Mo, and additional trace metals has reflected the hydrography of the basin and Bosphorus Strait, controlled largely by climate.

  8. Geochemistry of the Black Sea during the last 15 kyr: A protracted evolution of its hydrography and ecology

    NASA Astrophysics Data System (ADS)

    Piper, D. Z.

    2016-08-01

    The Black Sea is a 2200 m deep anoxic, marine sea connected to the Mediterranean Sea via the Dardanelles Strait, Marmara Sea, and the 3 km wide, 35 m deep Bosphorus Strait. The biogeochemistry of sediment from the Anatolia slope has recorded changes to the hydrography leading up to and following the input of Mediterranean water at ~9.4 ka (103 years B.P.), when global sea level rose to the level of the Bosphorus sill and high-salinity water from the Mediterranean began to spill into the then brackish lake. The water initially mixed little with the lake water but cascaded to the bottom where it remained essentially isolated for ~1.6 kyr, the time required to fill the basin from the bottom up at its present input rate. The accumulation of Mo in the seafloor sediments, a proxy of bottom-water anoxia, increased sharply at ~8.6 ka, when bacterial respiration in the bottom water advanced to SO42- reduction by the oxidation of organic detritus that settled out of the photic zone. Its accumulation remained elevated to ~5.6 ka, when it decreased 60%, only to again increase slightly at ~2.0 ka. The accumulation of Corg, a proxy of primary productivity, increased threefold to fourfold at ~7.8 ka, when upward mixing of the high-salinity bottom water replaced the then thin veneer of the brackish photic zone in less than 50 years. From that time onward, the accumulation of Corg, Mo, and additional trace metals has reflected the hydrography of the basin and Bosphorus Strait, controlled largely by climate.

  9. Degradation monitoring using probabilistic inference

    NASA Astrophysics Data System (ADS)

    Alpay, Bulent

    In order to increase safety and improve economy and performance in a nuclear power plant (NPP), the source and extent of component degradations should be identified before failures and breakdowns occur. It is also crucial for the next generation of NPPs, which are designed to have a long core life and high fuel burnup to have a degradation monitoring system in order to keep the reactor in a safe state, to meet the designed reactor core lifetime and to optimize the scheduled maintenance. Model-based methods are based on determining the inconsistencies between the actual and expected behavior of the plant, and use these inconsistencies for detection and diagnostics of degradations. By defining degradation as a random abrupt change from the nominal to a constant degraded state of a component, we employed nonlinear filtering techniques based on state/parameter estimation. We utilized a Bayesian recursive estimation formulation in the sequential probabilistic inference framework and constructed a hidden Markov model to represent a general physical system. By addressing the problem of a filter's inability to estimate an abrupt change, which is called the oblivious filter problem in nonlinear extensions of Kalman filtering, and the sample impoverishment problem in particle filtering, we developed techniques to modify filtering algorithms by utilizing additional data sources to improve the filter's response to this problem. We utilized a reliability degradation database that can be constructed from plant specific operational experience and test and maintenance reports to generate proposal densities for probable degradation modes. These are used in a multiple hypothesis testing algorithm. We then test samples drawn from these proposal densities with the particle filtering estimates based on the Bayesian recursive estimation formulation with the Metropolis Hastings algorithm, which is a well-known Markov chain Monte Carlo method (MCMC). This multiple hypothesis testing

  10. Melting Ice, Rising Seas

    NASA Video Gallery

    Sea level rise is an indicator that our planet is warming. Much of the world's population lives on or near the coast, and rising seas are something worth watching. Sea level can rise for two reason...

  11. Mammals of the Sea.

    ERIC Educational Resources Information Center

    Naturescope, 1986

    1986-01-01

    Presents information on sea mammals, including definitions and characteristics of cetaceans, pinnipeds, and sirenians. Contains descriptions of the teaching activities "Whale Music,""Draw A Whale to Scale,""Adopt a Sea Mammal," and "Sea Mammal Sleuths." (TW)

  12. Sea Ice

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.; Cavalieri, Donald J.

    2005-01-01

    Sea ice covers vast areas of the polar oceans, with ice extent in the Northern Hemisphere ranging from approximately 7 x 10(exp 6) sq km in September to approximately 15 x 10(exp 6) sq km in March and ice extent in the Southern Hemisphere ranging from approximately 3 x 10(exp 6) sq km in February to approximately 18 x 10(exp 6) sq km in September. These ice covers have major impacts on the atmosphere, oceans, and ecosystems of the polar regions, and so as changes occur in them there are potential widespread consequences. Satellite data reveal considerable interannual variability in both polar sea ice covers, and many studies suggest possible connections between the ice and various oscillations within the climate system, such as the Arctic Oscillation, North Atlantic Oscillation, and Antarctic Oscillation, or Southern Annular Mode. Nonetheless, statistically significant long-term trends are also apparent, including overall trends of decreased ice coverage in the Arctic and increased ice coverage in the Antarctic from late 1978 through the end of 2003, with the Antarctic ice increases following marked decreases in the Antarctic ice during the 1970s. For a detailed picture of the seasonally varying ice cover at the start of the 21st century, this chapter includes ice concentration maps for each month of 2001 for both the Arctic and the Antarctic, as well as an overview of what the satellite record has revealed about the two polar ice covers from the 1970s through 2003.

  13. An inference engine for embedded diagnostic systems

    NASA Technical Reports Server (NTRS)

    Fox, Barry R.; Brewster, Larry T.

    1987-01-01

    The implementation of an inference engine for embedded diagnostic systems is described. The system consists of two distinct parts. The first is an off-line compiler which accepts a propositional logical statement of the relationship between facts and conclusions and produces data structures required by the on-line inference engine. The second part consists of the inference engine and interface routines which accept assertions of fact and return the conclusions which necessarily follow. Given a set of assertions, it will generate exactly the conclusions which logically follow. At the same time, it will detect any inconsistencies which may propagate from an inconsistent set of assertions or a poorly formulated set of rules. The memory requirements are fixed and the worst case execution times are bounded at compile time. The data structures and inference algorithms are very simple and well understood. The data structures and algorithms are described in detail. The system has been implemented on Lisp, Pascal, and Modula-2.

  14. Experimental evidence for circular inference in schizophrenia

    NASA Astrophysics Data System (ADS)

    Jardri, Renaud; Duverne, Sandrine; Litvinova, Alexandra S.; Denève, Sophie

    2017-01-01

    Schizophrenia (SCZ) is a complex mental disorder that may result in some combination of hallucinations, delusions and disorganized thinking. Here SCZ patients and healthy controls (CTLs) report their level of confidence on a forced-choice task that manipulated the strength of sensory evidence and prior information. Neither group's responses can be explained by simple Bayesian inference. Rather, individual responses are best captured by a model with different degrees of circular inference. Circular inference refers to a corruption of sensory data by prior information and vice versa, leading us to `see what we expect' (through descending loops), to `expect what we see' (through ascending loops) or both. Ascending loops are stronger for SCZ than CTLs and correlate with the severity of positive symptoms. Descending loops correlate with the severity of negative symptoms. Both loops correlate with disorganized symptoms. The findings suggest that circular inference might mediate the clinical manifestations of SCZ.

  15. Bayesian Cosmological inference beyond statistical isotropy

    NASA Astrophysics Data System (ADS)

    Souradeep, Tarun; Das, Santanu; Wandelt, Benjamin

    2016-10-01

    With advent of rich data sets, computationally challenge of inference in cosmology has relied on stochastic sampling method. First, I review the widely used MCMC approach used to infer cosmological parameters and present a adaptive improved implementation SCoPE developed by our group. Next, I present a general method for Bayesian inference of the underlying covariance structure of random fields on a sphere. We employ the Bipolar Spherical Harmonic (BipoSH) representation of general covariance structure on the sphere. We illustrate the efficacy of the method with a principled approach to assess violation of statistical isotropy (SI) in the sky maps of Cosmic Microwave Background (CMB) fluctuations. The general, principled, approach to a Bayesian inference of the covariance structure in a random field on a sphere presented here has huge potential for application to other many aspects of cosmology and astronomy, as well as, more distant areas of research like geosciences and climate modelling.

  16. Experimental evidence for circular inference in schizophrenia

    PubMed Central

    Jardri, Renaud; Duverne, Sandrine; Litvinova, Alexandra S; Denève, Sophie

    2017-01-01

    Schizophrenia (SCZ) is a complex mental disorder that may result in some combination of hallucinations, delusions and disorganized thinking. Here SCZ patients and healthy controls (CTLs) report their level of confidence on a forced-choice task that manipulated the strength of sensory evidence and prior information. Neither group's responses can be explained by simple Bayesian inference. Rather, individual responses are best captured by a model with different degrees of circular inference. Circular inference refers to a corruption of sensory data by prior information and vice versa, leading us to ‘see what we expect' (through descending loops), to ‘expect what we see' (through ascending loops) or both. Ascending loops are stronger for SCZ than CTLs and correlate with the severity of positive symptoms. Descending loops correlate with the severity of negative symptoms. Both loops correlate with disorganized symptoms. The findings suggest that circular inference might mediate the clinical manifestations of SCZ. PMID:28139642

  17. Causal inference in economics and marketing

    PubMed Central

    Varian, Hal R.

    2016-01-01

    This is an elementary introduction to causal inference in economics written for readers familiar with machine learning methods. The critical step in any causal analysis is estimating the counterfactual—a prediction of what would have happened in the absence of the treatment. The powerful techniques used in machine learning may be useful for developing better estimates of the counterfactual, potentially improving causal inference. PMID:27382144

  18. Operation of the Bayes Inference Engine

    SciTech Connect

    Hanson, K.M.; Cunningham, G.S.

    1998-07-27

    The authors have developed a computer application, called the Bayes Inference Engine, to enable one to make inferences about models of a physical object from radiographs taken of it. In the BIE calculational models are represented by a data-flow diagram that can be manipulated by the analyst in a graphical-programming environment. The authors demonstrate the operation of the BIE in terms of examples of two-dimensional tomographic reconstruction including uncertainty estimation.

  19. Inferring ethnicity from mitochondrial DNA sequence

    PubMed Central

    2011-01-01

    Background The assignment of DNA samples to coarse population groups can be a useful but difficult task. One such example is the inference of coarse ethnic groupings for forensic applications. Ethnicity plays an important role in forensic investigation and can be inferred with the help of genetic markers. Being maternally inherited, of high copy number, and robust persistence in degraded samples, mitochondrial DNA may be useful for inferring coarse ethnicity. In this study, we compare the performance of methods for inferring ethnicity from the sequence of the hypervariable region of the mitochondrial genome. Results We present the results of comprehensive experiments conducted on datasets extracted from the mtDNA population database, showing that ethnicity inference based on support vector machines (SVM) achieves an overall accuracy of 80-90%, consistently outperforming nearest neighbor and discriminant analysis methods previously proposed in the literature. We also evaluate methods of handling missing data and characterize the most informative segments of the hypervariable region of the mitochondrial genome. Conclusions Support vector machines can be used to infer coarse ethnicity from a small region of mitochondrial DNA sequence with surprisingly high accuracy. In the presence of missing data, utilizing only the regions common to the training sequences and a test sequence proves to be the best strategy. Given these results, SVM algorithms are likely to also be useful in other DNA sequence classification applications. PMID:21554759

  20. Mitochondrial control region variability in Mytilus galloprovincialis populations from the central-Eastern Mediterranean Sea.

    PubMed

    Giantsis, Ioannis A; Abatzopoulos, Theodore J; Angelidis, Panagiotis; Apostolidis, Apostolos P

    2014-06-30

    The variable domain 1 (VD1) domain of the control region and a small segment of the rrnaL gene of the F mtDNA type were sequenced and analyzed in 174 specimens of Mytilus galloprovincialis. Samples were collected from eight locations in four Central-Eastern (CE) Mediterranean countries (Italy, Croatia, Greece and Turkey). A new primer, specific for the F mtDNA type, was designed for the sequencing procedure. In total 40 different haplotypes were recorded, 24 of which were unique. Aside from the two populations situated in Thermaikos gulf (Northern Aegean, Greece), relatively high levels of haplotype and nucleotide diversity were estimated for both Central and Eastern Mediterranean populations. Eight out of the 40 haplotypes were shared by at least three populations while two of them were found in all populations. ΦST and cluster analysis revealed lack of structuring among CE Mediterranean populations with the exception of those located at the Sea of Marmara and Croatian coast which were highly differentiated. Apart from the species' inherit dispersal ability, anthropogenic activities, such as the repeated translocations of mussel spat, seem to have played an important role in shaping the current genetic population structure of CE M. galloprovincialis mussels.

  1. Mitochondrial Control Region Variability in Mytilus galloprovincialis Populations from the Central-Eastern Mediterranean Sea

    PubMed Central

    Giantsis, Ioannis A.; Abatzopoulos, Theodore J.; Angelidis, Panagiotis; Apostolidis, Apostolos P.

    2014-01-01

    The variable domain 1 (VD1) domain of the control region and a small segment of the rrnaL gene of the F mtDNA type were sequenced and analyzed in 174 specimens of Mytilus galloprovincialis. Samples were collected from eight locations in four Central-Eastern (CE) Mediterranean countries (Italy, Croatia, Greece and Turkey). A new primer, specific for the F mtDNA type, was designed for the sequencing procedure. In total 40 different haplotypes were recorded, 24 of which were unique. Aside from the two populations situated in Thermaikos gulf (Northern Aegean, Greece), relatively high levels of haplotype and nucleotide diversity were estimated for both Central and Eastern Mediterranean populations. Eight out of the 40 haplotypes were shared by at least three populations while two of them were found in all populations. ΦST and cluster analysis revealed lack of structuring among CE Mediterranean populations with the exception of those located at the Sea of Marmara and Croatian coast which were highly differentiated. Apart from the species’ inherit dispersal ability, anthropogenic activities, such as the repeated translocations of mussel spat, seem to have played an important role in shaping the current genetic population structure of CE M. galloprovincialis mussels. PMID:24983478

  2. Perspectives of methods of laser monitoring of the atmosphere and sea surface

    NASA Astrophysics Data System (ADS)

    Pashayev, Arif; Tunaboylu, Bahadir; Usta, Metin; Sadixov, Ilham; Allahverdiyev, Kerim

    2016-01-01

    Laser monitoring (remote sensing) may be considered as the science of collecting and interpreting information about the atmosphere, earth and sea using sensors on earth, on platforms in our atmosphere (airplanes, balloons) or in space (satellites) without being in direct physical contact with them. Remote sensing by LIDARs (Light Identification Detection and Ranging) has wide applications as technique to probe the Earth's atmosphere, ocean and land surfaces. LIDARs are widely used to get knowledge of spatial and temporal variations in meteorological quantities (e.g. temperature, humidity, clouds and aerosol properties) and to monitor the changes in these quantities on different timescales. Subject of the present work is quite wide. It is rather difficult to perform analysis and to provide full knowledge about existing information. In the present work, in addition to the literature data, the information will be provided also about KA-09 aerosol LIDAR developed at the Marmara Research Centre of TÜBITAK (Turkish Scientific and technological Research Council) and also about KA-14 LIDAR developed at the National Aviation Academy of Azerbaijan for remote sensing of contaminations on water surfaces taking place during oil-gas production. The main goal of this paper is to give students insight in different remote sensing instruments and techniques (including their perspectives) that are used for the derivation of meteorological quantities and obtaining the information about water surface.

  3. Inference of Isoforms from Short Sequence Reads

    NASA Astrophysics Data System (ADS)

    Feng, Jianxing; Li, Wei; Jiang, Tao

    Due to alternative splicing events in eukaryotic species, the identification of mRNA isoforms (or splicing variants) is a difficult problem. Traditional experimental methods for this purpose are time consuming and cost ineffective. The emerging RNA-Seq technology provides a possible effective method to address this problem. Although the advantages of RNA-Seq over traditional methods in transcriptome analysis have been confirmed by many studies, the inference of isoforms from millions of short sequence reads (e.g., Illumina/Solexa reads) has remained computationally challenging. In this work, we propose a method to calculate the expression levels of isoforms and infer isoforms from short RNA-Seq reads using exon-intron boundary, transcription start site (TSS) and poly-A site (PAS) information. We first formulate the relationship among exons, isoforms, and single-end reads as a convex quadratic program, and then use an efficient algorithm (called IsoInfer) to search for isoforms. IsoInfer can calculate the expression levels of isoforms accurately if all the isoforms are known and infer novel isoforms from scratch. Our experimental tests on known mouse isoforms with both simulated expression levels and reads demonstrate that IsoInfer is able to calculate the expression levels of isoforms with an accuracy comparable to the state-of-the-art statistical method and a 60 times faster speed. Moreover, our tests on both simulated and real reads show that it achieves a good precision and sensitivity in inferring isoforms when given accurate exon-intron boundary, TSS and PAS information, especially for isoforms whose expression levels are significantly high.

  4. Colorful Underwater Sea Creatures

    ERIC Educational Resources Information Center

    McCutcheon, Heather

    2011-01-01

    In this article, the author describes a project wherein students created colorful underwater sea creatures. This project began with a discussion about underwater sea creatures and how they live. The first step was making the multi-colored tissue paper that would become sea creatures and seaweed. Once students had the shapes of their sea creatures…

  5. A lithosphere-scale structural model of the Barents Sea and Kara Sea region

    NASA Astrophysics Data System (ADS)

    Klitzke, P.; Faleide, J. I.; Scheck-Wenderoth, M.; Sippel, J.

    2014-07-01

    The Barents Sea and Kara Sea region as part of the European Arctic shelf, is geologically situated between the Proterozoic East-European Craton in the south and early Cenozoic passive margins in the north and the west. Proven and inferred hydrocarbon resources encouraged numerous industrial and academic studies in the last decades which brought along a wide spectrum of geological and geophysical data. By evaluating all available interpreted seismic refraction and reflection data, geological maps and previously published 3-D-models, we were able to develop a new lithosphere-scale 3-D-structural model for the greater Barents Sea and Kara Sea region. The sedimentary part of the model resolves four major megasequence boundaries (earliest Eocene, mid-Cretaceous, mid-Jurassic and mid-Permian). Downwards, the 3-D-structural model is complemented by the top crystalline crust, the Moho and a newly calculated lithosphere-asthenosphere boundary (LAB). The thickness distribution of the main megasequences delineates five major subdomains differentiating the region (the northern Kara Sea, the southern Kara Sea, the eastern Barents Sea, the western Barents Sea and the oceanic domain comprising the Norwegian-Greenland Sea and the Eurasia Basin). The vertical resolution of five sedimentary megasequences allows comparing for the first time the subsidence history of these domains directly. Relating the sedimentary structures with the deeper crustal/lithospheric configuration sheds some light on possible causative basin forming mechanisms that we discuss. The newly calculated LAB deepens from the typically shallow oceanic domain in three major steps beneath the Barents and Kara shelves towards the West-Siberian Basin in the east. Thereby, we relate the shallow continental LAB and slow/hot mantle beneath the southwestern Barents Sea with the formation of deep Paleozoic/Mesozoic rift basins. Thinnest continental lithosphere is observed beneath Svalbard and the NW Barents Sea where no

  6. Beaufort Sea: information update

    SciTech Connect

    Becker, P.R.

    1988-04-01

    The report is based on a multi-disciplinary meeting held March 6-7, 1985, as part of preparations for the Beaufort Sea Sale 97. The chapters are based on presentations given: The causeway effect: Modification of nearshore thermal regime resulting from causeways; Summertime sea ice intrusions in the Chukchi Sea; The deepwater limit of ice gouging on the Beaufort Sea shelf; Distribution, abundance, migration, harvest, and stock identity of Belukha Whales in the Beaufort Sea; Ringed seals in the Beaufort Sea; Beaufort Sea socioeconomics; The Baffin Island Oil Spill, (BIOS) Project.

  7. Estimating uncertainty of inference for validation

    SciTech Connect

    Booker, Jane M; Langenbrunner, James R; Hemez, Francois M; Ross, Timothy J

    2010-09-30

    We present a validation process based upon the concept that validation is an inference-making activity. This has always been true, but the association has not been as important before as it is now. Previously, theory had been confirmed by more data, and predictions were possible based on data. The process today is to infer from theory to code and from code to prediction, making the role of prediction somewhat automatic, and a machine function. Validation is defined as determining the degree to which a model and code is an accurate representation of experimental test data. Imbedded in validation is the intention to use the computer code to predict. To predict is to accept the conclusion that an observable final state will manifest; therefore, prediction is an inference whose goodness relies on the validity of the code. Quantifying the uncertainty of a prediction amounts to quantifying the uncertainty of validation, and this involves the characterization of uncertainties inherent in theory/models/codes and the corresponding data. An introduction to inference making and its associated uncertainty is provided as a foundation for the validation problem. A mathematical construction for estimating the uncertainty in the validation inference is then presented, including a possibility distribution constructed to represent the inference uncertainty for validation under uncertainty. The estimation of inference uncertainty for validation is illustrated using data and calculations from Inertial Confinement Fusion (ICF). The ICF measurements of neutron yield and ion temperature were obtained for direct-drive inertial fusion capsules at the Omega laser facility. The glass capsules, containing the fusion gas, were systematically selected with the intent of establishing a reproducible baseline of high-yield 10{sup 13}-10{sup 14} neutron output. The deuterium-tritium ratio in these experiments was varied to study its influence upon yield. This paper on validation inference is the

  8. Deep Learning for Population Genetic Inference

    PubMed Central

    Sheehan, Sara; Song, Yun S.

    2016-01-01

    Given genomic variation data from multiple individuals, computing the likelihood of complex population genetic models is often infeasible. To circumvent this problem, we introduce a novel likelihood-free inference framework by applying deep learning, a powerful modern technique in machine learning. Deep learning makes use of multilayer neural networks to learn a feature-based function from the input (e.g., hundreds of correlated summary statistics of data) to the output (e.g., population genetic parameters of interest). We demonstrate that deep learning can be effectively employed for population genetic inference and learning informative features of data. As a concrete application, we focus on the challenging problem of jointly inferring natural selection and demography (in the form of a population size change history). Our method is able to separate the global nature of demography from the local nature of selection, without sequential steps for these two factors. Studying demography and selection jointly is motivated by Drosophila, where pervasive selection confounds demographic analysis. We apply our method to 197 African Drosophila melanogaster genomes from Zambia to infer both their overall demography, and regions of their genome under selection. We find many regions of the genome that have experienced hard sweeps, and fewer under selection on standing variation (soft sweep) or balancing selection. Interestingly, we find that soft sweeps and balancing selection occur more frequently closer to the centromere of each chromosome. In addition, our demographic inference suggests that previously estimated bottlenecks for African Drosophila melanogaster are too extreme. PMID:27018908

  9. Inferring learners' knowledge from their actions.

    PubMed

    Rafferty, Anna N; LaMar, Michelle M; Griffiths, Thomas L

    2015-04-01

    Watching another person take actions to complete a goal and making inferences about that person's knowledge is a relatively natural task for people. This ability can be especially important in educational settings, where the inferences can be used for assessment, diagnosing misconceptions, and providing informative feedback. In this paper, we develop a general framework for automatically making such inferences based on observed actions; this framework is particularly relevant for inferring student knowledge in educational games and other interactive virtual environments. Our approach relies on modeling action planning: We formalize the problem as a Markov decision process in which one must choose what actions to take to complete a goal, where choices will be dependent on one's beliefs about how actions affect the environment. We use a variation of inverse reinforcement learning to infer these beliefs. Through two lab experiments, we show that this model can recover people's beliefs in a simple environment, with accuracy comparable to that of human observers. We then demonstrate that the model can be used to provide real-time feedback and to model data from an existing educational game.

  10. Scene Construction, Visual Foraging, and Active Inference

    PubMed Central

    Mirza, M. Berk; Adams, Rick A.; Mathys, Christoph D.; Friston, Karl J.

    2016-01-01

    This paper describes an active inference scheme for visual searches and the perceptual synthesis entailed by scene construction. Active inference assumes that perception and action minimize variational free energy, where actions are selected to minimize the free energy expected in the future. This assumption generalizes risk-sensitive control and expected utility theory to include epistemic value; namely, the value (or salience) of information inherent in resolving uncertainty about the causes of ambiguous cues or outcomes. Here, we apply active inference to saccadic searches of a visual scene. We consider the (difficult) problem of categorizing a scene, based on the spatial relationship among visual objects where, crucially, visual cues are sampled myopically through a sequence of saccadic eye movements. This means that evidence for competing hypotheses about the scene has to be accumulated sequentially, calling upon both prediction (planning) and postdiction (memory). Our aim is to highlight some simple but fundamental aspects of the requisite functional anatomy; namely, the link between approximate Bayesian inference under mean field assumptions and functional segregation in the visual cortex. This link rests upon the (neurobiologically plausible) process theory that accompanies the normative formulation of active inference for Markov decision processes. In future work, we hope to use this scheme to model empirical saccadic searches and identify the prior beliefs that underwrite intersubject variability in the way people forage for information in visual scenes (e.g., in schizophrenia). PMID:27378899

  11. Computational inference of neural information flow networks.

    PubMed

    Smith, V Anne; Yu, Jing; Smulders, Tom V; Hartemink, Alexander J; Jarvis, Erich D

    2006-11-24

    Determining how information flows along anatomical brain pathways is a fundamental requirement for understanding how animals perceive their environments, learn, and behave. Attempts to reveal such neural information flow have been made using linear computational methods, but neural interactions are known to be nonlinear. Here, we demonstrate that a dynamic Bayesian network (DBN) inference algorithm we originally developed to infer nonlinear transcriptional regulatory networks from gene expression data collected with microarrays is also successful at inferring nonlinear neural information flow networks from electrophysiology data collected with microelectrode arrays. The inferred networks we recover from the songbird auditory pathway are correctly restricted to a subset of known anatomical paths, are consistent with timing of the system, and reveal both the importance of reciprocal feedback in auditory processing and greater information flow to higher-order auditory areas when birds hear natural as opposed to synthetic sounds. A linear method applied to the same data incorrectly produces networks with information flow to non-neural tissue and over paths known not to exist. To our knowledge, this study represents the first biologically validated demonstration of an algorithm to successfully infer neural information flow networks.

  12. Reliability of the Granger causality inference

    NASA Astrophysics Data System (ADS)

    Zhou, Douglas; Zhang, Yaoyu; Xiao, Yanyang; Cai, David

    2014-04-01

    How to characterize information flows in physical, biological, and social systems remains a major theoretical challenge. Granger causality (GC) analysis has been widely used to investigate information flow through causal interactions. We address one of the central questions in GC analysis, that is, the reliability of the GC evaluation and its implications for the causal structures extracted by this analysis. Our work reveals that the manner in which a continuous dynamical process is projected or coarse-grained to a discrete process has a profound impact on the reliability of the GC inference, and different sampling may potentially yield completely opposite inferences. This inference hazard is present for both linear and nonlinear processes. We emphasize that there is a hazard of reaching incorrect conclusions about network topologies, even including statistical (such as small-world or scale-free) properties of the networks, when GC analysis is blindly applied to infer the network topology. We demonstrate this using a small-world network for which a drastic loss of small-world attributes occurs in the reconstructed network using the standard GC approach. We further show how to resolve the paradox that the GC analysis seemingly becomes less reliable when more information is incorporated using finer and finer sampling. Finally, we present strategies to overcome these inference artifacts in order to obtain a reliable GC result.

  13. Deep Learning for Population Genetic Inference.

    PubMed

    Sheehan, Sara; Song, Yun S

    2016-03-01

    Given genomic variation data from multiple individuals, computing the likelihood of complex population genetic models is often infeasible. To circumvent this problem, we introduce a novel likelihood-free inference framework by applying deep learning, a powerful modern technique in machine learning. Deep learning makes use of multilayer neural networks to learn a feature-based function from the input (e.g., hundreds of correlated summary statistics of data) to the output (e.g., population genetic parameters of interest). We demonstrate that deep learning can be effectively employed for population genetic inference and learning informative features of data. As a concrete application, we focus on the challenging problem of jointly inferring natural selection and demography (in the form of a population size change history). Our method is able to separate the global nature of demography from the local nature of selection, without sequential steps for these two factors. Studying demography and selection jointly is motivated by Drosophila, where pervasive selection confounds demographic analysis. We apply our method to 197 African Drosophila melanogaster genomes from Zambia to infer both their overall demography, and regions of their genome under selection. We find many regions of the genome that have experienced hard sweeps, and fewer under selection on standing variation (soft sweep) or balancing selection. Interestingly, we find that soft sweeps and balancing selection occur more frequently closer to the centromere of each chromosome. In addition, our demographic inference suggests that previously estimated bottlenecks for African Drosophila melanogaster are too extreme.

  14. Computationally efficient Bayesian inference for inverse problems.

    SciTech Connect

    Marzouk, Youssef M.; Najm, Habib N.; Rahn, Larry A.

    2007-10-01

    Bayesian statistics provides a foundation for inference from noisy and incomplete data, a natural mechanism for regularization in the form of prior information, and a quantitative assessment of uncertainty in the inferred results. Inverse problems - representing indirect estimation of model parameters, inputs, or structural components - can be fruitfully cast in this framework. Complex and computationally intensive forward models arising in physical applications, however, can render a Bayesian approach prohibitive. This difficulty is compounded by high-dimensional model spaces, as when the unknown is a spatiotemporal field. We present new algorithmic developments for Bayesian inference in this context, showing strong connections with the forward propagation of uncertainty. In particular, we introduce a stochastic spectral formulation that dramatically accelerates the Bayesian solution of inverse problems via rapid evaluation of a surrogate posterior. We also explore dimensionality reduction for the inference of spatiotemporal fields, using truncated spectral representations of Gaussian process priors. These new approaches are demonstrated on scalar transport problems arising in contaminant source inversion and in the inference of inhomogeneous material or transport properties. We also present a Bayesian framework for parameter estimation in stochastic models, where intrinsic stochasticity may be intermingled with observational noise. Evaluation of a likelihood function may not be analytically tractable in these cases, and thus several alternative Markov chain Monte Carlo (MCMC) schemes, operating on the product space of the observations and the parameters, are introduced.

  15. Hierarchical cosmic shear power spectrum inference

    NASA Astrophysics Data System (ADS)

    Alsing, Justin; Heavens, Alan; Jaffe, Andrew H.; Kiessling, Alina; Wandelt, Benjamin; Hoffmann, Till

    2016-02-01

    We develop a Bayesian hierarchical modelling approach for cosmic shear power spectrum inference, jointly sampling from the posterior distribution of the cosmic shear field and its (tomographic) power spectra. Inference of the shear power spectrum is a powerful intermediate product for a cosmic shear analysis, since it requires very few model assumptions and can be used to perform inference on a wide range of cosmological models a posteriori without loss of information. We show that joint posterior for the shear map and power spectrum can be sampled effectively by Gibbs sampling, iteratively drawing samples from the map and power spectrum, each conditional on the other. This approach neatly circumvents difficulties associated with complicated survey geometry and masks that plague frequentist power spectrum estimators, since the power spectrum inference provides prior information about the field in masked regions at every sampling step. We demonstrate this approach for inference of tomographic shear E-mode, B-mode and EB-cross power spectra from a simulated galaxy shear catalogue with a number of important features; galaxies distributed on the sky and in redshift with photometric redshift uncertainties, realistic random ellipticity noise for every galaxy and a complicated survey mask. The obtained posterior distributions for the tomographic power spectrum coefficients recover the underlying simulated power spectra for both E- and B-modes.

  16. GeoSEA: Geodetic Earthquake Observatory on the Seafloor

    NASA Astrophysics Data System (ADS)

    Kopp, Heidrun; Lange, Dietrich; Flueh, Ernst R.; Petersen, Florian; Behrmann, Jan-Hinrich; Devey, Colin

    2014-05-01

    monitor station settlement in two horizontal directions. Data can be acquired and recorded autonomously subsea without system or human intervention for up to 6 years. These data can then be recovered via the integrated high-speed acoustic telemetry link without recovering the seafloor units. When requested to do so, the stored data will be transmitted wirelessly up to the sea surface to the GeoSURF wave glider for onward transmission via a satellite link. Targets for GeoSEA are the marine sector of the North Anatolian fault zone in the Marmara Sea, where a joint French-German array will be installed in late 2014 as well as the central sector of the South America - Nazca convergent plate boundary along the Iquique segment, offshore Northern Chile. Here, the GeoSEA array will be installed in late 2015 to monitor crustal deformation. Mobile autonomous seafloor arrays for continuous measurement of active seafloor deformation in hazard zones have the potential to lead to transformative discoveries of plate boundary/fault zone tectonic processes and address a novel element of marine geophysical research.

  17. Children's and Adults' Judgments of the Certainty of Deductive Inferences, Inductive Inferences, and Guesses

    ERIC Educational Resources Information Center

    Pillow, Bradford H.; Pearson, RaeAnne M.; Hecht, Mary; Bremer, Amanda

    2010-01-01

    Children and adults rated their own certainty following inductive inferences, deductive inferences, and guesses. Beginning in kindergarten, participants rated deductions as more certain than weak inductions or guesses. Deductions were rated as more certain than strong inductions beginning in Grade 3, and fourth-grade children and adults…

  18. Using Alien Coins to Test Whether Simple Inference Is Bayesian

    ERIC Educational Resources Information Center

    Cassey, Peter; Hawkins, Guy E.; Donkin, Chris; Brown, Scott D.

    2016-01-01

    Reasoning and inference are well-studied aspects of basic cognition that have been explained as statistically optimal Bayesian inference. Using a simplified experimental design, we conducted quantitative comparisons between Bayesian inference and human inference at the level of individuals. In 3 experiments, with more than 13,000 participants, we…

  19. Automatic transformations in the inference process

    SciTech Connect

    Veroff, R. L.

    1980-07-01

    A technique for incorporating automatic transformations into processes such as the application of inference rules, subsumption, and demodulation provides a mechanism for improving search strategies for theorem proving problems arising from the field of program verification. The incorporation of automatic transformations into the inference process can alter the search space for a given problem, and is particularly useful for problems having broad rather than deep proofs. The technique can also be used to permit the generation of inferences that might otherwise be blocked and to build some commutativity or associativity into the unification process. Appropriate choice of transformations, and new literal clashing and unification algorithms for applying them, showed significant improvement on several real problems according to several distinct criteria. 22 references, 1 figure.

  20. Identification and Inference for Econometric Models

    NASA Astrophysics Data System (ADS)

    Andrews, Donald W. K.; Stock, James H.

    2005-07-01

    This volume contains the papers presented in honor of the lifelong achievements of Thomas J. Rothenberg on the occasion of his retirement. The authors of the chapters include many of the leading econometricians of our day, and the chapters address topics of current research significance in econometric theory. The chapters cover four themes: identification and efficient estimation in econometrics, asymptotic approximations to the distributions of econometric estimators and tests, inference involving potentially nonstationary time series, such as processes that might have a unit autoregressive root, and nonparametric and semiparametric inference. Several of the chapters provide overviews and treatments of basic conceptual issues, while others advance our understanding of the properties of existing econometric procedures and/or propose new ones. Specific topics include identification in nonlinear models, inference with weak instruments, tests for nonstationary in time series and panel data, generalized empirical likelihood estimation, and the bootstrap.

  1. Single board system for fuzzy inference

    NASA Technical Reports Server (NTRS)

    Symon, James R.; Watanabe, Hiroyuki

    1991-01-01

    The very large scale integration (VLSI) implementation of a fuzzy logic inference mechanism allows the use of rule-based control and decision making in demanding real-time applications. Researchers designed a full custom VLSI inference engine. The chip was fabricated using CMOS technology. The chip consists of 688,000 transistors of which 476,000 are used for RAM memory. The fuzzy logic inference engine board system incorporates the custom designed integrated circuit into a standard VMEbus environment. The Fuzzy Logic system uses Transistor-Transistor Logic (TTL) parts to provide the interface between the Fuzzy chip and a standard, double height VMEbus backplane, allowing the chip to perform application process control through the VMEbus host. High level C language functions hide details of the hardware system interface from the applications level programmer. The first version of the board was installed on a robot at Oak Ridge National Laboratory in January of 1990.

  2. Network inference in the nonequilibrium steady state

    NASA Astrophysics Data System (ADS)

    Dettmer, Simon L.; Nguyen, H. Chau; Berg, Johannes

    2016-11-01

    Nonequilibrium systems lack an explicit characterization of their steady state like the Boltzmann distribution for equilibrium systems. This has drastic consequences for the inference of the parameters of a model when its dynamics lacks detailed balance. Such nonequilibrium systems occur naturally in applications like neural networks and gene regulatory networks. Here, we focus on the paradigmatic asymmetric Ising model and show that we can learn its parameters from independent samples of the nonequilibrium steady state. We present both an exact inference algorithm and a computationally more efficient, approximate algorithm for weak interactions based on a systematic expansion around mean-field theory. Obtaining expressions for magnetizations and two- and three-point spin correlations, we establish that these observables are sufficient to infer the model parameters. Further, we discuss the symmetries characterizing the different orders of the expansion around the mean field and show how different types of dynamics can be distinguished on the basis of samples from the nonequilibrium steady state.

  3. A Learning Algorithm for Multimodal Grammar Inference.

    PubMed

    D'Ulizia, A; Ferri, F; Grifoni, P

    2011-12-01

    The high costs of development and maintenance of multimodal grammars in integrating and understanding input in multimodal interfaces lead to the investigation of novel algorithmic solutions in automating grammar generation and in updating processes. Many algorithms for context-free grammar inference have been developed in the natural language processing literature. An extension of these algorithms toward the inference of multimodal grammars is necessary for multimodal input processing. In this paper, we propose a novel grammar inference mechanism that allows us to learn a multimodal grammar from its positive samples of multimodal sentences. The algorithm first generates the multimodal grammar that is able to parse the positive samples of sentences and, afterward, makes use of two learning operators and the minimum description length metrics in improving the grammar description and in avoiding the over-generalization problem. The experimental results highlight the acceptable performances of the algorithm proposed in this paper since it has a very high probability of parsing valid sentences.

  4. Quality of computationally inferred gene ontology annotations.

    PubMed

    Skunca, Nives; Altenhoff, Adrian; Dessimoz, Christophe

    2012-05-01

    Gene Ontology (GO) has established itself as the undisputed standard for protein function annotation. Most annotations are inferred electronically, i.e. without individual curator supervision, but they are widely considered unreliable. At the same time, we crucially depend on those automated annotations, as most newly sequenced genomes are non-model organisms. Here, we introduce a methodology to systematically and quantitatively evaluate electronic annotations. By exploiting changes in successive releases of the UniProt Gene Ontology Annotation database, we assessed the quality of electronic annotations in terms of specificity, reliability, and coverage. Overall, we not only found that electronic annotations have significantly improved in recent years, but also that their reliability now rivals that of annotations inferred by curators when they use evidence other than experiments from primary literature. This work provides the means to identify the subset of electronic annotations that can be relied upon-an important outcome given that >98% of all annotations are inferred without direct curation.

  5. A formal model of interpersonal inference

    PubMed Central

    Moutoussis, Michael; Trujillo-Barreto, Nelson J.; El-Deredy, Wael; Dolan, Raymond J.; Friston, Karl J.

    2014-01-01

    Introduction: We propose that active Bayesian inference—a general framework for decision-making—can equally be applied to interpersonal exchanges. Social cognition, however, entails special challenges. We address these challenges through a novel formulation of a formal model and demonstrate its psychological significance. Method: We review relevant literature, especially with regards to interpersonal representations, formulate a mathematical model and present a simulation study. The model accommodates normative models from utility theory and places them within the broader setting of Bayesian inference. Crucially, we endow people's prior beliefs, into which utilities are absorbed, with preferences of self and others. The simulation illustrates the model's dynamics and furnishes elementary predictions of the theory. Results: (1) Because beliefs about self and others inform both the desirability and plausibility of outcomes, in this framework interpersonal representations become beliefs that have to be actively inferred. This inference, akin to “mentalizing” in the psychological literature, is based upon the outcomes of interpersonal exchanges. (2) We show how some well-known social-psychological phenomena (e.g., self-serving biases) can be explained in terms of active interpersonal inference. (3) Mentalizing naturally entails Bayesian updating of how people value social outcomes. Crucially this includes inference about one's own qualities and preferences. Conclusion: We inaugurate a Bayes optimal framework for modeling intersubject variability in mentalizing during interpersonal exchanges. Here, interpersonal representations are endowed with explicit functional and affective properties. We suggest the active inference framework lends itself to the study of psychiatric conditions where mentalizing is distorted. PMID:24723872

  6. Gene-network inference by message passing

    NASA Astrophysics Data System (ADS)

    Braunstein, A.; Pagnani, A.; Weigt, M.; Zecchina, R.

    2008-01-01

    The inference of gene-regulatory processes from gene-expression data belongs to the major challenges of computational systems biology. Here we address the problem from a statistical-physics perspective and develop a message-passing algorithm which is able to infer sparse, directed and combinatorial regulatory mechanisms. Using the replica technique, the algorithmic performance can be characterized analytically for artificially generated data. The algorithm is applied to genome-wide expression data of baker's yeast under various environmental conditions. We find clear cases of combinatorial control, and enrichment in common functional annotations of regulated genes and their regulators.

  7. Microwave remote sensing of sea ice

    NASA Technical Reports Server (NTRS)

    Comiso, J. C.

    1988-01-01

    The long term objectives are: (1) to understand the physics of the multispectral microwave radiative characteristics of sea ice as it goes through different phases; (2) to improve characterization of sea ice cover using satellite microwave sensors; and (3) to study ice/ocean physical and biological processes associated with polynya formations and variability of the marginal sea ice region. Two field experiments were conducted to pursue these objectives. One involved measurements of radiative and physical characteristics of sea ice from a ship during a 3-month long cruise through the Weddell Sea ice pack during the Austral winter of 1986. The other involved similar measurements from two aircrafts and a submarine over the Central Arctic and Greenland Sea region. Preliminary results have already led to an enhanced understanding of the microwave signatures of pancake ice, nilas, first year ice, multiyear ice and effects of snow cover. Coastal and deep ocean polynyas and their role in bottom water formation and ocean circulation were studied using a time series of ice images from SMMR. An unsupervised cluster analysis of Arctic sea ice using SMMR and THIR emissivity and brightness temperature data was implemented. The analysis indicates the existence of several unique and persistent clusters in the Central Arctic region during winter and that the sum of the area of these clusters excluding those of first year ice is about 20 percent less than minimum ice cover area inferred from a previous summer data. This result is consistent with saline surface for some multiyear ice floes as observed during MIZEZ and suggests that a significant fraction of multiyear ice floes in the Arctic have first year ice signatures.

  8. Vulnerability indicators of sea water intrusion.

    PubMed

    Werner, Adrian D; Ward, James D; Morgan, Leanne K; Simmons, Craig T; Robinson, Neville I; Teubner, Michael D

    2012-01-01

    In this paper, simple indicators of the propensity for sea water intrusion (SWI) to occur (referred to as "SWI vulnerability indicators") are devised. The analysis is based on an existing analytical solution for the steady-state position of a sharp fresh water-salt water interface. Interface characteristics, that is, the wedge toe location and sea water volume, are used in quantifying SWI in both confined and unconfined aquifers. Rates-of-change (partial derivatives of the analytical solution) in the wedge toe or sea water volume are used to quantify the aquifer vulnerability to various stress situations, including (1) sea-level rise; (2) change in recharge (e.g., due to climate change); and (3) change in seaward discharge. A selection of coastal aquifer cases is used to apply the SWI vulnerability indicators, and the proposed methodology produces interpretations of SWI vulnerability that are broadly consistent with more comprehensive investigations. Several inferences regarding SWI vulnerability arise from the analysis, including: (1) sea-level rise impacts are more extensive in aquifers with head-controlled rather than flux-controlled inland boundaries, whereas the opposite is true for recharge change impacts; (2) sea-level rise does not induce SWI in constant-discharge confined aquifers; (3) SWI vulnerability varies depending on the causal factor, and therefore vulnerability composites are needed that differentiate vulnerability to such threats as sea-level rise, climate change, and changes in seaward groundwater discharge. We contend that the approach is an improvement over existing methods for characterizing SWI vulnerability, because the method has theoretical underpinnings and yet calculations are simple, although the coastal aquifer conceptualization is highly idealized.

  9. Timescales alter the inferred strength and temporal consistency of intraspecific diet specialization

    USGS Publications Warehouse

    Novak, Mark; Tinker, M. Tim

    2015-01-01

    Many populations consist of individuals that differ substantially in their diets. Quantification of the magnitude and temporal consistency of such intraspecific diet variation is needed to understand its importance, but the extent to which different approaches for doing so reflect instantaneous vs. time-aggregated measures of individual diets may bias inferences. We used direct observations of sea otter individuals (Enhydra lutris nereis) to assess how: (1) the timescale of sampling, (2) under-sampling, and (3) the incidence- vs. frequency-based consideration of prey species affect the inferred strength and consistency of intraspecific diet variation. Analyses of feeding observations aggregated over hourly to annual intervals revealed a substantial bias associated with time aggregation that decreases the inferred magnitude of specialization and increases the inferred consistency of individuals’ diets. Time aggregation also made estimates of specialization more sensitive to the consideration of prey frequency, which decreased estimates relative to the use of prey incidence; time aggregation did not affect the extent to which under-sampling contributed to its overestimation. Our analyses demonstrate the importance of studying intraspecific diet variation with an explicit consideration of time and thereby suggest guidelines for future empirical efforts. Failure to consider time will likely produce inconsistent predictions regarding the effects of intraspecific variation on predator–prey interactions.

  10. Processing of SeaMARC swath sonar imagery

    SciTech Connect

    Pratson, L.; Malinverno, A.; Edwards, M.; Ryan, W. )

    1990-05-01

    Side-scan swath sonar systems have become an increasingly important means of mapping the sea floor. Two such systems are the deep-towed, high-resolution SeaMARC I sonar, which has a variable swath width of up to 5 km, and the shallow-towed, lower-resolution SeaMARC II sonar, which has a swath width of 10 km. The sea-floor imagery of acoustic backscatter output by the SeaMARC sonars is analogous to aerial photographs and airborne side-looking radar images of continental topography. Geologic interpretation of the sea-floor imagery is greatly facilitated by image processing. Image processing of the digital backscatter data involves removal of noise by median filtering, spatial filtering to remove sonar scans of anomalous intensity, across-track corrections to remove beam patterns caused by nonuniform response of the sonar transducers to changes in incident angle, and contrast enhancement by histogram equalization to maximize the available dynamic range. Correct geologic interpretation requires submarine structural fabrics to be displayed in their proper locations and orientations. Geographic projection of sea-floor imagery is achieved by merging the enhanced imagery with the sonar vehicle navigation and correcting for vehicle attitude. Co-registration of bathymetry with sonar imagery introduces sea-floor relief and permits the imagery to be displayed in three-dimensional perspectives, furthering the ability of the marine geologist to infer the processes shaping formerly hidden subsea terrains.

  11. Directions of strong winds on Mars inferred

    NASA Technical Reports Server (NTRS)

    Howard, A. D.

    1972-01-01

    Asymmetrical crater shadings and diffuse light and dark streaks visible on the photography returned by the 1969 Mars flyby of Mariners 6 and 7 are probably eolian in origin. Wind directions inferred from mapping of these features parallel motions of observed global dust storms or relate to expected patterns of topographic funneling of winds.

  12. Decision generation tools and Bayesian inference

    NASA Astrophysics Data System (ADS)

    Jannson, Tomasz; Wang, Wenjian; Forrester, Thomas; Kostrzewski, Andrew; Veeris, Christian; Nielsen, Thomas

    2014-05-01

    Digital Decision Generation (DDG) tools are important software sub-systems of Command and Control (C2) systems and technologies. In this paper, we present a special type of DDGs based on Bayesian Inference, related to adverse (hostile) networks, including such important applications as terrorism-related networks and organized crime ones.

  13. Efficient Bayesian inference for ARFIMA processes

    NASA Astrophysics Data System (ADS)

    Graves, T.; Gramacy, R. B.; Franzke, C. L. E.; Watkins, N. W.

    2015-03-01

    Many geophysical quantities, like atmospheric temperature, water levels in rivers, and wind speeds, have shown evidence of long-range dependence (LRD). LRD means that these quantities experience non-trivial temporal memory, which potentially enhances their predictability, but also hampers the detection of externally forced trends. Thus, it is important to reliably identify whether or not a system exhibits LRD. In this paper we present a modern and systematic approach to the inference of LRD. Rather than Mandelbrot's fractional Gaussian noise, we use the more flexible Autoregressive Fractional Integrated Moving Average (ARFIMA) model which is widely used in time series analysis, and of increasing interest in climate science. Unlike most previous work on the inference of LRD, which is frequentist in nature, we provide a systematic treatment of Bayesian inference. In particular, we provide a new approximate likelihood for efficient parameter inference, and show how nuisance parameters (e.g. short memory effects) can be integrated over in order to focus on long memory parameters, and hypothesis testing more directly. We illustrate our new methodology on the Nile water level data, with favorable comparison to the standard estimators.

  14. Statistical inference for serial dilution assay data.

    PubMed

    Lee, M L; Whitmore, G A

    1999-12-01

    Serial dilution assays are widely employed for estimating substance concentrations and minimum inhibitory concentrations. The Poisson-Bernoulli model for such assays is appropriate for count data but not for continuous measurements that are encountered in applications involving substance concentrations. This paper presents practical inference methods based on a log-normal model and illustrates these methods using a case application involving bacterial toxins.

  15. Inverse Ising inference with correlated samples

    NASA Astrophysics Data System (ADS)

    Obermayer, Benedikt; Levine, Erel

    2014-12-01

    Correlations between two variables of a high-dimensional system can be indicative of an underlying interaction, but can also result from indirect effects. Inverse Ising inference is a method to distinguish one from the other. Essentially, the parameters of the least constrained statistical model are learned from the observed correlations such that direct interactions can be separated from indirect correlations. Among many other applications, this approach has been helpful for protein structure prediction, because residues which interact in the 3D structure often show correlated substitutions in a multiple sequence alignment. In this context, samples used for inference are not independent but share an evolutionary history on a phylogenetic tree. Here, we discuss the effects of correlations between samples on global inference. Such correlations could arise due to phylogeny but also via other slow dynamical processes. We present a simple analytical model to address the resulting inference biases, and develop an exact method accounting for background correlations in alignment data by combining phylogenetic modeling with an adaptive cluster expansion algorithm. We find that popular reweighting schemes are only marginally effective at removing phylogenetic bias, suggest a rescaling strategy that yields better results, and provide evidence that our conclusions carry over to the frequently used mean-field approach to the inverse Ising problem.

  16. Permutation inference for the general linear model

    PubMed Central

    Winkler, Anderson M.; Ridgway, Gerard R.; Webster, Matthew A.; Smith, Stephen M.; Nichols, Thomas E.

    2014-01-01

    Permutation methods can provide exact control of false positives and allow the use of non-standard statistics, making only weak assumptions about the data. With the availability of fast and inexpensive computing, their main limitation would be some lack of flexibility to work with arbitrary experimental designs. In this paper we report on results on approximate permutation methods that are more flexible with respect to the experimental design and nuisance variables, and conduct detailed simulations to identify the best method for settings that are typical for imaging research scenarios. We present a generic framework for permutation inference for complex general linear models (glms) when the errors are exchangeable and/or have a symmetric distribution, and show that, even in the presence of nuisance effects, these permutation inferences are powerful while providing excellent control of false positives in a wide range of common and relevant imaging research scenarios. We also demonstrate how the inference on glm parameters, originally intended for independent data, can be used in certain special but useful cases in which independence is violated. Detailed examples of common neuroimaging applications are provided, as well as a complete algorithm – the “randomise” algorithm – for permutation inference with the glm. PMID:24530839

  17. Perceptual inferences about indeterminate arrangements of figures.

    PubMed

    Moreno-Ríos, Sergio; Rojas-Barahona, Cristian A; García-Madruga, Juan A

    2014-05-01

    Previous studies in spatial propositional reasoning showed that adults use a particular strategy for making representations and inferences from indeterminate descriptions (those consistent with different alternatives). They do not initially represent all the alternatives, but construct a unified mental representation that includes a kind of mental footnote. Only when the task requires access to alternatives is the unified representation re-inspected. The degree of generalisation of this proposal to other perceptual situations was evaluated in three experiments with children, adolescents and adults, using a perceptual inference task with diagrammatic premises that gave information about the location of one of three possible objects. Results obtained with this very quick perceptual task support the kind of representation proposed from propositional spatial reasoning studies. However, children and adults differed in accuracy, with the results gradually changing with age: indeterminacy leads adults to require extra time for understanding and inferring alternatives, whereas children commit errors. These results could help inform us of how people can make inferences from diagrammatic information and make wrong interpretations.

  18. "Comments on Slavin": Synthesizing Causal Inferences

    ERIC Educational Resources Information Center

    Briggs, Derek C.

    2008-01-01

    When causal inferences are to be synthesized across multiple studies, efforts to establish the magnitude of a causal effect should be balanced by an effort to evaluate the generalizability of the effect. The evaluation of generalizability depends on two factors that are given little attention in current syntheses: construct validity and external…

  19. Evolutionary inference via the Poisson Indel Process.

    PubMed

    Bouchard-Côté, Alexandre; Jordan, Michael I

    2013-01-22

    We address the problem of the joint statistical inference of phylogenetic trees and multiple sequence alignments from unaligned molecular sequences. This problem is generally formulated in terms of string-valued evolutionary processes along the branches of a phylogenetic tree. The classic evolutionary process, the TKF91 model [Thorne JL, Kishino H, Felsenstein J (1991) J Mol Evol 33(2):114-124] is a continuous-time Markov chain model composed of insertion, deletion, and substitution events. Unfortunately, this model gives rise to an intractable computational problem: The computation of the marginal likelihood under the TKF91 model is exponential in the number of taxa. In this work, we present a stochastic process, the Poisson Indel Process (PIP), in which the complexity of this computation is reduced to linear. The Poisson Indel Process is closely related to the TKF91 model, differing only in its treatment of insertions, but it has a global characterization as a Poisson process on the phylogeny. Standard results for Poisson processes allow key computations to be decoupled, which yields the favorable computational profile of inference under the PIP model. We present illustrative experiments in which Bayesian inference under the PIP model is compared with separate inference of phylogenies and alignments.

  20. Causal Inferences with Group Based Trajectory Models

    ERIC Educational Resources Information Center

    Haviland, Amelia M.; Nagin, Daniel S.

    2005-01-01

    A central theme of research on human development and psychopathology is whether a therapeutic intervention or a turning-point event, such as a family break-up, alters the trajectory of the behavior under study. This paper lays out and applies a method for using observational longitudinal data to make more confident causal inferences about the…

  1. The Role of Inference in Effective Communication.

    ERIC Educational Resources Information Center

    Brown, Paula M.; Dell, Gary S.

    A study was conducted to determine whether speakers vary the explicitness of a message in accordance with a listener's likelihood of inferring the intended information. Thirty-six hearing and hearing-impaired college students were asked to read a series of 20 paragraphs. After each one, they were to re-tell the story in their own words to the…

  2. HIERARCHICAL PROBABILISTIC INFERENCE OF COSMIC SHEAR

    SciTech Connect

    Schneider, Michael D.; Dawson, William A.; Hogg, David W.; Marshall, Philip J.; Bard, Deborah J.; Meyers, Joshua; Lang, Dustin

    2015-07-01

    Point estimators for the shearing of galaxy images induced by gravitational lensing involve a complex inverse problem in the presence of noise, pixelization, and model uncertainties. We present a probabilistic forward modeling approach to gravitational lensing inference that has the potential to mitigate the biased inferences in most common point estimators and is practical for upcoming lensing surveys. The first part of our statistical framework requires specification of a likelihood function for the pixel data in an imaging survey given parameterized models for the galaxies in the images. We derive the lensing shear posterior by marginalizing over all intrinsic galaxy properties that contribute to the pixel data (i.e., not limited to galaxy ellipticities) and learn the distributions for the intrinsic galaxy properties via hierarchical inference with a suitably flexible conditional probabilitiy distribution specification. We use importance sampling to separate the modeling of small imaging areas from the global shear inference, thereby rendering our algorithm computationally tractable for large surveys. With simple numerical examples we demonstrate the improvements in accuracy from our importance sampling approach, as well as the significance of the conditional distribution specification for the intrinsic galaxy properties when the data are generated from an unknown number of distinct galaxy populations with different morphological characteristics.

  3. Making statistical inferences about software reliability

    NASA Technical Reports Server (NTRS)

    Miller, Douglas R.

    1988-01-01

    Failure times of software undergoing random debugging can be modelled as order statistics of independent but nonidentically distributed exponential random variables. Using this model inferences can be made about current reliability and, if debugging continues, future reliability. This model also shows the difficulty inherent in statistical verification of very highly reliable software such as that used by digital avionics in commercial aircraft.

  4. Inference and the Introductory Statistics Course

    ERIC Educational Resources Information Center

    Pfannkuch, Maxine; Regan, Matt; Wild, Chris; Budgett, Stephanie; Forbes, Sharleen; Harraway, John; Parsonage, Ross

    2011-01-01

    This article sets out some of the rationale and arguments for making major changes to the teaching and learning of statistical inference in introductory courses at our universities by changing from a norm-based, mathematical approach to more conceptually accessible computer-based approaches. The core problem of the inferential argument with its…

  5. What Children Infer from Social Categories

    ERIC Educational Resources Information Center

    Diesendruck, Gil; Eldror, Ehud

    2011-01-01

    Children hold the belief that social categories have essences. We investigated what kinds of properties children feel licensed to infer about a person based on social category membership. Seventy-two 4-6-year-olds were introduced to novel social categories defined as having one internal--psychological or biological--and one external--behavioral or…

  6. Active interoceptive inference and the emotional brain

    PubMed Central

    Friston, Karl J.

    2016-01-01

    We review a recent shift in conceptions of interoception and its relationship to hierarchical inference in the brain. The notion of interoceptive inference means that bodily states are regulated by autonomic reflexes that are enslaved by descending predictions from deep generative models of our internal and external milieu. This re-conceptualization illuminates several issues in cognitive and clinical neuroscience with implications for experiences of selfhood and emotion. We first contextualize interoception in terms of active (Bayesian) inference in the brain, highlighting its enactivist (embodied) aspects. We then consider the key role of uncertainty or precision and how this might translate into neuromodulation. We next examine the implications for understanding the functional anatomy of the emotional brain, surveying recent observations on agranular cortex. Finally, we turn to theoretical issues, namely, the role of interoception in shaping a sense of embodied self and feelings. We will draw links between physiological homoeostasis and allostasis, early cybernetic ideas of predictive control and hierarchical generative models in predictive processing. The explanatory scope of interoceptive inference ranges from explanations for autism and depression, through to consciousness. We offer a brief survey of these exciting developments. This article is part of the themed issue ‘Interoception beyond homeostasis: affect, cognition and mental health’. PMID:28080966

  7. Linguistic Markers of Inference Generation While Reading

    ERIC Educational Resources Information Center

    Clinton, Virginia; Carlson, Sarah E.; Seipel, Ben

    2016-01-01

    Words can be informative linguistic markers of psychological constructs. The purpose of this study is to examine associations between word use and the process of making meaningful connections to a text while reading (i.e., inference generation). To achieve this purpose, think-aloud data from third-fifth grade students (N = 218) reading narrative…

  8. Campbell's and Rubin's Perspectives on Causal Inference

    ERIC Educational Resources Information Center

    West, Stephen G.; Thoemmes, Felix

    2010-01-01

    Donald Campbell's approach to causal inference (D. T. Campbell, 1957; W. R. Shadish, T. D. Cook, & D. T. Campbell, 2002) is widely used in psychology and education, whereas Donald Rubin's causal model (P. W. Holland, 1986; D. B. Rubin, 1974, 2005) is widely used in economics, statistics, medicine, and public health. Campbell's approach focuses on…

  9. Rates inferred from the space debris catalog

    SciTech Connect

    Canavan, G.H.

    1996-08-01

    Collision and fragmentation rates are inferred from the AFSPC space debris catalog and compare with estimates from other treatments. The collision rate is evaluated without approximation. The fragmentation rate requires additional empirical assessments. The number of fragments per collision is low compared to analytic and numerical treatments, is peaked low, and falls rapidly with altitude.

  10. Quasi-Experimental Designs for Causal Inference

    ERIC Educational Resources Information Center

    Kim, Yongnam; Steiner, Peter

    2016-01-01

    When randomized experiments are infeasible, quasi-experimental designs can be exploited to evaluate causal treatment effects. The strongest quasi-experimental designs for causal inference are regression discontinuity designs, instrumental variable designs, matching and propensity score designs, and comparative interrupted time series designs. This…

  11. Making statistical inferences about software reliability

    NASA Technical Reports Server (NTRS)

    Miller, Douglas R.

    1986-01-01

    Failure times of software undergoing random debugging can be modeled as order statistics of independent but nonidentically distributed exponential random variables. Using this model inferences can be made about current reliability and, if debugging continues, future reliability. This model also shows the difficulty inherent in statistical verification of very highly reliable software such as that used by digital avionics in commercial aircraft.

  12. Double jeopardy in inferring cognitive processes

    PubMed Central

    Fific, Mario

    2014-01-01

    Inferences we make about underlying cognitive processes can be jeopardized in two ways due to problematic forms of aggregation. First, averaging across individuals is typically considered a very useful tool for removing random variability. The threat is that averaging across subjects leads to averaging across different cognitive strategies, thus harming our inferences. The second threat comes from the construction of inadequate research designs possessing a low diagnostic accuracy of cognitive processes. For that reason we introduced the systems factorial technology (SFT), which has primarily been designed to make inferences about underlying processing order (serial, parallel, coactive), stopping rule (terminating, exhaustive), and process dependency. SFT proposes that the minimal research design complexity to learn about n number of cognitive processes should be equal to 2n. In addition, SFT proposes that (a) each cognitive process should be controlled by a separate experimental factor, and (b) The saliency levels of all factors should be combined in a full factorial design. In the current study, the author cross combined the levels of jeopardies in a 2 × 2 analysis, leading to four different analysis conditions. The results indicate a decline in the diagnostic accuracy of inferences made about cognitive processes due to the presence of each jeopardy in isolation and when combined. The results warrant the development of more individual subject analyses and the utilization of full-factorial (SFT) experimental designs. PMID:25374545

  13. Causal Inferences in the Campbellian Validity System

    ERIC Educational Resources Information Center

    Lund, Thorleif

    2010-01-01

    The purpose of the present paper is to critically examine causal inferences and internal validity as defined by Campbell and co-workers. Several arguments are given against their counterfactual effect definition, and this effect definition should be considered inadequate for causal research in general. Moreover, their defined independence between…

  14. Inferring Internet Denial-of-Service Activity

    DTIC Science & Technology

    2007-11-02

    Inferring Internet Denial-of-Service Activity David Moore CAIDA San Diego Supercomputer Center University of California, San Diego dmoore@caida.org...the local network topology. kc claffy and Colleen Shannon at CAIDA provided support and valuable feed- back throughout the project. David Wetherall

  15. Investigating Mathematics Teachers' Thoughts of Statistical Inference

    ERIC Educational Resources Information Center

    Yang, Kai-Lin

    2012-01-01

    Research on statistical cognition and application suggests that statistical inference concepts are commonly misunderstood by students and even misinterpreted by researchers. Although some research has been done on students' misunderstanding or misconceptions of confidence intervals (CIs), few studies explore either students' or mathematics…

  16. Centennial-scale paleoceanography during sapropel S1 deposition in the NE Aegean (Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Triantaphyllou, Maria; Gogou, Alexandra; Dimiza, Margarita; Kostopoulou, Sofia; Parinos, Constantine; Roussakis, Grigoris; Geraga, Maria; Skampa, Elisavet; Bouloubassi, Ioanna; Fleitmann, Dominik; Zervakis, Vassilis; Velaoras, Dimitris; Diamantopoulou, Antonia; Sampatakaki, Angeliki; Lykousis, Vassilis

    2016-04-01

    Combined micropaleontological and geochemical analyses in the high-sedimentation gravity core M-4G, provided new centennial scale paleoceanographic data for the sapropel S1 deposition in the NE Aegean Sea. Sapropel layer S1a (10.2-8.0 ka) is deposited in dysoxic to oxic bottom waters; sediments are characterized by the high abundance of benthic foraminifers Chilostomella mediterranensis and Globobulimina affinis that are able to tolerate surface sediment and/or pore water oxygen depletion and the presence of the oxic mesotrophic-eutrophic U. mediterranea. Adequate preservation of organic matter is proven by the high organic carbon and loliolide and isololiolide contents, whereas the biomarker record and the abundances of eutrophic planktonic foraminifera document enhanced productivity. Both alkenone-based SSTs and δO18 G. bulloides records indicate coolings at 8.2 ka (S1a) and at ~7.8 ka (S1 interruption). Sapropelic layer S1b (7.7-6.4 ka) is characterized by rather oxic conditions marked by the prominent increase of U. mediterranea. The highly fluctuating SSTs demonstrate repeated coolings and associated dense water formation; major event at 7.4 ka, followed by cold spells at 7.0, 6.8, 6.5 ka. Besides, the increase of algal biomarkers, labile organic matter-feeding foraminifera and eutrophic planktonic species pinpoints rise in in situ marine productivity, which is enhanced by more efficient vertical convection due to repeated cold events. The associated contributions of labile marine organic matter (OM) along with fresher terrestrial OM inputs after ~7.7 ka BP imply alternative/ additional than the north Aegean riverine borderland sources for the influx of organic matter at the south Limnos Basin, also related to the inflow of highly productive Marmara/Black Sea waters

  17. Inferring late-Holocene climate in the Ecuadorian Andes using a chironomid-based temperature inference model

    NASA Astrophysics Data System (ADS)

    Matthews-Bird, Frazer; Brooks, Stephen J.; Holden, Philip B.; Montoya, Encarni; Gosling, William D.

    2016-06-01

    Presented here is the first chironomid calibration data set for tropical South America. Surface sediments were collected from 59 lakes across Bolivia (15 lakes), Peru (32 lakes), and Ecuador (12 lakes) between 2004 and 2013 over an altitudinal gradient from 150 m above sea level (a.s.l) to 4655 m a.s.l, between 0-17° S and 64-78° W. The study sites cover a mean annual temperature (MAT) gradient of 25 °C. In total, 55 chironomid taxa were identified in the 59 calibration data set lakes. When used as a single explanatory variable, MAT explains 12.9 % of the variance (λ1/λ2 = 1.431). Two inference models were developed using weighted averaging (WA) and Bayesian methods. The best-performing model using conventional statistical methods was a WA (inverse) model (R2jack = 0.890; RMSEPjack = 2.404 °C, RMSEP - root mean squared error of prediction; mean biasjack = -0.017 °C; max biasjack = 4.665 °C). The Bayesian method produced a model with R2jack = 0.909, RMSEPjack = 2.373 °C, mean biasjack = 0.598 °C, and max biasjack = 3.158 °C. Both models were used to infer past temperatures from a ca. 3000-year record from the tropical Andes of Ecuador, Laguna Pindo. Inferred temperatures fluctuated around modern-day conditions but showed significant departures at certain intervals (ca. 1600 cal yr BP; ca. 3000-2500 cal yr BP). Both methods (WA and Bayesian) showed similar patterns of temperature variability; however, the magnitude of fluctuations differed. In general the WA method was more variable and often underestimated Holocene temperatures (by ca. -7 ± 2.5 °C relative to the modern period). The Bayesian method provided temperature anomaly estimates for cool periods that lay within the expected range of the Holocene (ca. -3 ± 3.4 °C). The error associated with both reconstructions is consistent with a constant temperature of 20 °C for the past 3000 years. We would caution, however, against an over-interpretation at this stage. The reconstruction can only

  18. Geoid undulations and gravity anomalies over the Aral Sea, the Black Sea and the Caspian Sea from a combined GEOS-3/SEASAT/GEOSAT altimeter data set

    NASA Technical Reports Server (NTRS)

    Au, Andrew Y.; Brown, Richard D.; Welker, Jean E.

    1991-01-01

    Satellite-based altimetric data taken by GOES-3, SEASAT, and GEOSAT over the Aral Sea, the Black Sea, and the Caspian Sea are analyzed and a least squares collocation technique is used to predict the geoid undulations on a 0.25x0.25 deg. grid and to transform these geoid undulations to free air gravity anomalies. Rapp's 180x180 geopotential model is used as the reference surface for the collocation procedure. The result of geoid to gravity transformation is, however, sensitive to the information content of the reference geopotential model used. For example, considerable detailed surface gravity data were incorporated into the reference model over the Black Sea, resulting in a reference model with significant information content at short wavelengths. Thus, estimation of short wavelength gravity anomalies from gridded geoid heights is generally reliable over regions such as the Black Sea, using the conventional collocation technique with local empirical covariance functions. Over regions such as the Caspian Sea, where detailed surface data are generally not incorporated into the reference model, unconventional techniques are needed to obtain reliable gravity anomalies. Based on the predicted gravity anomalies over these inland seas, speculative tectonic structures are identified and geophysical processes are inferred.

  19. Aral Sea basin: a sea dies, a sea also rises.

    PubMed

    Glantz, Michael H

    2007-06-01

    The thesis of this article is quite different from many other theses of papers, books, and articles on the Aral Sea. It is meant to purposely highlight the reality of the situation in Central Asia: the Aral Sea that was once a thriving body of water is no more. That sea is dead. What does exist in its place are the Aral seas: there are in essence three bodies of water, one of which is being purposefully restored and its level is rising (the Little Aral), and two others which are still marginally connected, although they continue to decline in level (the Big Aral West and the Big Aral East). In 1960 the level of the sea was about 53 m above sea level. By 2006 the level had dropped by 23 m to 30 m above sea level. This was not a scenario generated by a computer model. It was a process of environmental degradation played out in real life in a matter of a few decades, primarily as a result of human activities. Despite wishes and words to the contrary, it will take a heroic global effort to save what remains of the Big Aral. It would also take a significant degree of sacrifice by people and governments in the region to restore the Big Aral to an acceptable level, given that the annual rate of flow reaching the Amudarya River delta is less than a 10th of what it was several decades ago. Conferring World Heritage status to the Aral Sea(s) could spark restoration efforts for the Big Aral.

  20. Holocene paleo-sea level changes along the coast of Rio de Janeiro, southern Brazil: Comment on Castro et al. (2014).

    PubMed

    Angulo, Rodolfo J; Giannini, Paulo C F; Souza, Maria Cristina DE; Lessa, Guilherme C

    2016-01-01

    The present work discusses and reinterprets paleo-sea level indicators used to build Holocene sea-level curve for the coast of Rio de Janeiro at former works. We conclude that: (a) the paleo-sea levels inferred by vermetid remains show that sea-level has fallen over the past 4400 years, at least; (b) the paleo-sea level inferred by the beachrock facies and dated shells of Jaconé shows that sea-level was near the present elevation between 8198 and 5786 years before present; and (c) several shells from other beachrocks were deposited probably thousands of years after the specimens died and consequently do not allow precise reconstructions of paleo-sea levels. These conclusions differ from the conclusions of the original paper.

  1. 7 CFR 1437.310 - Sea grass and sea oats.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Sea grass and sea oats. 1437.310 Section 1437.310... Determining Coverage Using Value § 1437.310 Sea grass and sea oats. (a) Sea grass and sea oats are value loss... boundaries; and (3) Be managed and maintained using acceptable growing practices for the geographical...

  2. 7 CFR 1437.310 - Sea grass and sea oats.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Sea grass and sea oats. 1437.310 Section 1437.310... Determining Coverage Using Value § 1437.310 Sea grass and sea oats. (a) Sea grass and sea oats are value loss... boundaries; and (3) Be managed and maintained using acceptable growing practices for the geographical...

  3. 7 CFR 1437.310 - Sea grass and sea oats.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Sea grass and sea oats. 1437.310 Section 1437.310... Determining Coverage Using Value § 1437.310 Sea grass and sea oats. (a) Sea grass and sea oats are value loss... boundaries; and (3) Be managed and maintained using acceptable growing practices for the geographical...

  4. 7 CFR 1437.310 - Sea grass and sea oats.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Sea grass and sea oats. 1437.310 Section 1437.310... Determining Coverage Using Value § 1437.310 Sea grass and sea oats. (a) Sea grass and sea oats are value loss..., as determined by CCC. (e) The land, waterbed, or facility in which the eligible commodity was...

  5. 7 CFR 1437.310 - Sea grass and sea oats.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Sea grass and sea oats. 1437.310 Section 1437.310... Determining Coverage Using Value § 1437.310 Sea grass and sea oats. (a) Sea grass and sea oats are value loss..., as determined by CCC. (e) The land, waterbed, or facility in which the eligible commodity was...

  6. Tasman Leakage of intermediate waters as inferred from Argo floats

    NASA Astrophysics Data System (ADS)

    Rosell-Fieschi, Miquel; Rintoul, Stephen R.; Gourrion, Jeröme; Pelegrí, Josep L.

    2013-10-01

    use Argo float trajectories to infer ocean current velocity at the sea surface and 1000 dbar near Australia. The East Australian Current flows southward along the east coast of Australia at both surface and intermediate levels, but only the intermediate waters leak round the southern tip of Tasmania and cross the Great Australian Bight. We calculate the transport of Antarctic Intermediate Water (AAIW) between the southern Australian coast and the Antarctic Circumpolar Current (ACC) as the velocity at 1000 dbar times the layer thickness. Between March 2006 and December 2012, the Eulerian AAIW transport through 147°E ranges between 0 and 12.0 sverdrup (Sv). The mean Tasman Leakage of intermediate waters from the Pacific Ocean into the Indian Ocean, obtained using all Argo data until March 2013, is 3.8 ± 1.3 Sv. The mean intermediate water transport into the Indian Ocean through 115°E increases to 5.2 ± 1.8 Sv due to contributions from the westward recirculation of ACC waters.

  7. Inferring directed climatic interactions with renormalized partial directed coherence and directed partial correlation

    NASA Astrophysics Data System (ADS)

    Tirabassi, Giulio; Sommerlade, Linda; Masoller, Cristina

    2017-03-01

    Inferring interactions between processes promises deeper insight into mechanisms underlying network phenomena. Renormalised partial directed coherence is a frequency-domain representation of the concept of Granger causality, while directed partial correlation is an alternative approach for quantifying Granger causality in the time domain. Both methodologies have been successfully applied to neurophysiological signals for detecting directed relationships. This paper introduces their application to climatological time series. We first discuss the application to El Niño-Southern Oscillation—Monsoon interaction and then apply the methodologies to the more challenging air-sea interaction in the South Atlantic Convergence Zone (SACZ). In the first case, the results obtained are fully consistent with the present knowledge in climate modeling, while in the second case, the results are, as expected, less clear, and to fully elucidate the SACZ air-sea interaction, further investigations on the specificity and sensitivity of these methodologies are needed.

  8. Deep sea waste disposal

    SciTech Connect

    Kester, D.R.; Burt, W.V.; Capuzzo, J.M.; Park, P.K.; Ketchum, B.W.; Duedall, I.W.

    1985-01-01

    The book presents papers on the marine disposal of wastes. Topics considered include incineration at sea, the modelling and biological effects of industrial wastes, microbial studies of ocean dumping, deep-sea mining wastes, the chemical analysis of ferromanganese nodules, and economic aspects of deep-sea disposal.

  9. All That Unplowed Sea

    ERIC Educational Resources Information Center

    MOSAIC, 1975

    1975-01-01

    Hunting and gathering at sea may fast be approaching their productive limits. Aquaculture - farming at sea - linked to conservation represents the sea's promise. If the system works, it might prove to be the key to supplying large amounts of food and fresh water at no cost in nonrenewable energy resources. (BT)

  10. Eutrophication Increases Phytoplankton Methylmercury Concentrations in a Coastal Sea-A Baltic Sea Case Study.

    PubMed

    Soerensen, Anne L; Schartup, Amina T; Gustafsson, Erik; Gustafsson, Bo G; Undeman, Emma; Björn, Erik

    2016-11-01

    Eutrophication is expanding worldwide, but its implication for production and bioaccumulation of neurotoxic monomethylmercury (MeHg) is unknown. We developed a mercury (Hg) biogeochemical model for the Baltic Sea and used it to investigate the impact of eutrophication on phytoplankton MeHg concentrations. For model evaluation, we measured total methylated Hg (MeHgT) in the Baltic Sea and found low concentrations (39 ± 16 fM) above the halocline and high concentrations in anoxic waters (1249 ± 369 fM). To close the Baltic Sea MeHgT budget, we inferred an average normoxic water column Hg(II) methylation rate constant of 2 × 10(-4) d(-1). We used the model to compare Baltic Sea's present-day (2005-2014) eutrophic state to an oligo/mesotrophic scenario. Eutrophication increases primary production and export of organic matter and associated Hg to the sediment effectively removing Hg from the active biogeochemical cycle; this results in a 27% lower present-day water column Hg reservoir. However, increase in organic matter production and remineralization stimulates microbial Hg methylation resulting in a seasonal increase in both water and phytoplankton MeHg reservoirs above the halocline. Previous studies of systems dominated by external MeHg sources or benthic production found eutrophication to decrease MeHg levels in plankton. This Baltic Sea study shows that in systems with MeHg production in the normoxic water column eutrophication can increase phytoplankton MeHg content.

  11. Inferring network topology via the propagation process

    NASA Astrophysics Data System (ADS)

    Zeng, An

    2013-11-01

    Inferring the network topology from the dynamics is a fundamental problem, with wide applications in geology, biology, and even counter-terrorism. Based on the propagation process, we present a simple method to uncover the network topology. A numerical simulation on artificial networks shows that our method enjoys a high accuracy in inferring the network topology. We find that the infection rate in the propagation process significantly influences the accuracy, and that each network corresponds to an optimal infection rate. Moreover, the method generally works better in large networks. These finding are confirmed in both real social and nonsocial networks. Finally, the method is extended to directed networks, and a similarity measure specific for directed networks is designed.

  12. Interoceptive inference, emotion, and the embodied self.

    PubMed

    Seth, Anil K

    2013-11-01

    The concept of the brain as a prediction machine has enjoyed a resurgence in the context of the Bayesian brain and predictive coding approaches within cognitive science. To date, this perspective has been applied primarily to exteroceptive perception (e.g., vision, audition), and action. Here, I describe a predictive, inferential perspective on interoception: 'interoceptive inference' conceives of subjective feeling states (emotions) as arising from actively-inferred generative (predictive) models of the causes of interoceptive afferents. The model generalizes 'appraisal' theories that view emotions as emerging from cognitive evaluations of physiological changes, and it sheds new light on the neurocognitive mechanisms that underlie the experience of body ownership and conscious selfhood in health and in neuropsychiatric illness.

  13. Pointwise probability reinforcements for robust statistical inference.

    PubMed

    Frénay, Benoît; Verleysen, Michel

    2014-02-01

    Statistical inference using machine learning techniques may be difficult with small datasets because of abnormally frequent data (AFDs). AFDs are observations that are much more frequent in the training sample that they should be, with respect to their theoretical probability, and include e.g. outliers. Estimates of parameters tend to be biased towards models which support such data. This paper proposes to introduce pointwise probability reinforcements (PPRs): the probability of each observation is reinforced by a PPR and a regularisation allows controlling the amount of reinforcement which compensates for AFDs. The proposed solution is very generic, since it can be used to robustify any statistical inference method which can be formulated as a likelihood maximisation. Experiments show that PPRs can be easily used to tackle regression, classification and projection: models are freed from the influence of outliers. Moreover, outliers can be filtered manually since an abnormality degree is obtained for each observation.

  14. Neural Circuit Inference from Function to Structure.

    PubMed

    Real, Esteban; Asari, Hiroki; Gollisch, Tim; Meister, Markus

    2017-01-23

    Advances in technology are opening new windows on the structural connectivity and functional dynamics of brain circuits. Quantitative frameworks are needed that integrate these data from anatomy and physiology. Here, we present a modeling approach that creates such a link. The goal is to infer the structure of a neural circuit from sparse neural recordings, using partial knowledge of its anatomy as a regularizing constraint. We recorded visual responses from the output neurons of the retina, the ganglion cells. We then generated a systematic sequence of circuit models that represents retinal neurons and connections and fitted them to the experimental data. The optimal models faithfully recapitulated the ganglion cell outputs. More importantly, they made predictions about dynamics and connectivity among unobserved neurons internal to the circuit, and these were subsequently confirmed by experiment. This circuit inference framework promises to facilitate the integration and understanding of big data in neuroscience.

  15. Dopamine, reward learning, and active inference

    PubMed Central

    FitzGerald, Thomas H. B.; Dolan, Raymond J.; Friston, Karl

    2015-01-01

    Temporal difference learning models propose phasic dopamine signaling encodes reward prediction errors that drive learning. This is supported by studies where optogenetic stimulation of dopamine neurons can stand in lieu of actual reward. Nevertheless, a large body of data also shows that dopamine is not necessary for learning, and that dopamine depletion primarily affects task performance. We offer a resolution to this paradox based on an hypothesis that dopamine encodes the precision of beliefs about alternative actions, and thus controls the outcome-sensitivity of behavior. We extend an active inference scheme for solving Markov decision processes to include learning, and show that simulated dopamine dynamics strongly resemble those actually observed during instrumental conditioning. Furthermore, simulated dopamine depletion impairs performance but spares learning, while simulated excitation of dopamine neurons drives reward learning, through aberrant inference about outcome states. Our formal approach provides a novel and parsimonious reconciliation of apparently divergent experimental findings. PMID:26581305

  16. The empirical accuracy of uncertain inference models

    NASA Technical Reports Server (NTRS)

    Vaughan, David S.; Yadrick, Robert M.; Perrin, Bruce M.; Wise, Ben P.

    1987-01-01

    Uncertainty is a pervasive feature of the domains in which expert systems are designed to function. Research design to test uncertain inference methods for accuracy and robustness, in accordance with standard engineering practice is reviewed. Several studies were conducted to assess how well various methods perform on problems constructed so that correct answers are known, and to find out what underlying features of a problem cause strong or weak performance. For each method studied, situations were identified in which performance deteriorates dramatically. Over a broad range of problems, some well known methods do only about as well as a simple linear regression model, and often much worse than a simple independence probability model. The results indicate that some commercially available expert system shells should be used with caution, because the uncertain inference models that they implement can yield rather inaccurate results.

  17. The NIFTY way of Bayesian signal inference

    SciTech Connect

    Selig, Marco

    2014-12-05

    We introduce NIFTY, 'Numerical Information Field Theory', a software package for the development of Bayesian signal inference algorithms that operate independently from any underlying spatial grid and its resolution. A large number of Bayesian and Maximum Entropy methods for 1D signal reconstruction, 2D imaging, as well as 3D tomography, appear formally similar, but one often finds individualized implementations that are neither flexible nor easily transferable. Signal inference in the framework of NIFTY can be done in an abstract way, such that algorithms, prototyped in 1D, can be applied to real world problems in higher-dimensional settings. NIFTY as a versatile library is applicable and already has been applied in 1D, 2D, 3D and spherical settings. A recent application is the D{sup 3}PO algorithm targeting the non-trivial task of denoising, deconvolving, and decomposing photon observations in high energy astronomy.

  18. Spectral likelihood expansions for Bayesian inference

    NASA Astrophysics Data System (ADS)

    Nagel, Joseph B.; Sudret, Bruno

    2016-03-01

    A spectral approach to Bayesian inference is presented. It pursues the emulation of the posterior probability density. The starting point is a series expansion of the likelihood function in terms of orthogonal polynomials. From this spectral likelihood expansion all statistical quantities of interest can be calculated semi-analytically. The posterior is formally represented as the product of a reference density and a linear combination of polynomial basis functions. Both the model evidence and the posterior moments are related to the expansion coefficients. This formulation avoids Markov chain Monte Carlo simulation and allows one to make use of linear least squares instead. The pros and cons of spectral Bayesian inference are discussed and demonstrated on the basis of simple applications from classical statistics and inverse modeling.

  19. Unified Theory of Inference for Text Understanding

    DTIC Science & Technology

    1986-11-25

    reataurant script is recognized, script application would lead to inferences such as identifying the waiter as ’ ’the waiter who is employed by the...relations between the objects. Objects have names as a convenience for the system modeler, but the names are not used for purposes other than...intent is that we can consider talking to be a frame with a talker slot which must be filled by a person. This is just a convenient notation; the

  20. Inferring Trust Based on Similarity with TILLIT

    NASA Astrophysics Data System (ADS)

    Tavakolifard, Mozhgan; Herrmann, Peter; Knapskog, Svein J.

    A network of people having established trust relations and a model for propagation of related trust scores are fundamental building blocks in many of today’s most successful e-commerce and recommendation systems. However, the web of trust is often too sparse to predict trust values between non-familiar people with high accuracy. Trust inferences are transitive associations among users in the context of an underlying social network and may provide additional information to alleviate the consequences of the sparsity and possible cold-start problems. Such approaches are helpful, provided that a complete trust path exists between the two users. An alternative approach to the problem is advocated in this paper. Based on collaborative filtering one can exploit the like-mindedness resp. similarity of individuals to infer trust to yet unknown parties which increases the trust relations in the web. For instance, if one knows that with respect to a specific property, two parties are trusted alike by a large number of different trusters, one can assume that they are similar. Thus, if one has a certain degree of trust to the one party, one can safely assume a very similar trustworthiness of the other one. In an attempt to provide high quality recommendations and proper initial trust values even when no complete trust propagation path or user profile exists, we propose TILLIT — a model based on combination of trust inferences and user similarity. The similarity is derived from the structure of the trust graph and users’ trust behavior as opposed to other collaborative-filtering based approaches which use ratings of items or user’s profile. We describe an algorithm realizing the approach based on a combination of trust inferences and user similarity, and validate the algorithm using a real large-scale data-set.

  1. Ambiguity and Uncertainty in Probabilistic Inference.

    DTIC Science & Technology

    1983-09-01

    Bruner , J. S. Going beyond the information given. In J. S. Bruner et al. (Eds.), Contemporary approaches to cognition. Cambridge, MA: Harvard University...82179the non-additivity of complementary probabilities, current psychological theories of risk, and Ellsberg’s original paradox. The model is tested in...most psychological work on inference has been guided by a Bayesian or subjectivist view of probability, increasing concerns have been expressed about

  2. A Theory of Diagnostic Inference: Judging Causality.

    DTIC Science & Technology

    1983-08-01

    Lepper, 1981) and the lack of search for disconfirming hypotheses (e.g., Mynatt , et al. 1977, 1978; Tweney, et al., 1980), we stress that a...perception de la causalite. Paris: Vrin, 1946. Mynatt , C. R., Doherty, M. Z., a Tweney, R. D. Confirmation bias in a simulated research environment: An...experimental study of scientific inference. Quarterly Journal of Experimental Psychology, 1977, 29, 85-95. =4 57 Mynatt , C. R., Doherty, M. E., & Tweney, R

  3. Thermodynamics of statistical inference by cells.

    PubMed

    Lang, Alex H; Fisher, Charles K; Mora, Thierry; Mehta, Pankaj

    2014-10-03

    The deep connection between thermodynamics, computation, and information is now well established both theoretically and experimentally. Here, we extend these ideas to show that thermodynamics also places fundamental constraints on statistical estimation and learning. To do so, we investigate the constraints placed by (nonequilibrium) thermodynamics on the ability of biochemical signaling networks to estimate the concentration of an external signal. We show that accuracy is limited by energy consumption, suggesting that there are fundamental thermodynamic constraints on statistical inference.

  4. A Unified Approach to Abductive Inference

    DTIC Science & Technology

    2014-09-30

    performance hacks . Alchemy Lite allows for fast, exact inference for models formulated in terms of TML, as well as the ability to update models with...Kimelfeld (bennyk@gmail.com) Molham Aref (molham.aref@logicblox.com) Charles Rivers Analytics Avi Pfeffer (apfeffer@cra.com) Facebook ...works at Yahoo; now at Facebook ) BAE systems Gregory Sullivan (gregory.sullivan@baesystems.com) Raytheon Kenric P Nelson

  5. The Caspian Sea Environment

    NASA Astrophysics Data System (ADS)

    Kostianoy, Andrey; Kosarev, A.

    The systematic description of the knowledge accumulated on the physical oceanography, marine chemistry and pollution, and marine biology of the Caspian Sea forms the basis of this book. It presents the principal characteristic features of the environmental conditions of the sea and their changes in the second half of the 20th century. At present, the principal problems of the Caspian Sea are related to the interannual sea level changes and their forecast and to the estimation of the intensity of the chemical pollution of the sea and its impact upon the biota.

  6. Inferring Genetic Ancestry: Opportunities, Challenges, and Implications

    PubMed Central

    Royal, Charmaine D.; Novembre, John; Fullerton, Stephanie M.; Goldstein, David B.; Long, Jeffrey C.; Bamshad, Michael J.; Clark, Andrew G.

    2010-01-01

    Increasing public interest in direct-to-consumer (DTC) genetic ancestry testing has been accompanied by growing concern about issues ranging from the personal and societal implications of the testing to the scientific validity of ancestry inference. The very concept of “ancestry” is subject to misunderstanding in both the general and scientific communities. What do we mean by ancestry? How exactly is ancestry measured? How far back can such ancestry be defined and by which genetic tools? How do we validate inferences about ancestry in genetic research? What are the data that demonstrate our ability to do this correctly? What can we say and what can we not say from our research findings and the test results that we generate? This white paper from the American Society of Human Genetics (ASHG) Ancestry and Ancestry Testing Task Force builds upon the 2008 ASHG Ancestry Testing Summary Statement in providing a more in-depth analysis of key scientific and non-scientific aspects of genetic ancestry inference in academia and industry. It culminates with recommendations for advancing the current debate and facilitating the development of scientifically based, ethically sound, and socially attentive guidelines concerning the use of these continually evolving technologies. PMID:20466090

  7. Bayesian Inference for Skewed Stable Distributions

    NASA Astrophysics Data System (ADS)

    Shokripour, Mona; Nassiri, Vahid; Mohammadpour, Adel

    2011-03-01

    Stable distributions are a class of distributions which allow skewness and heavy tail. Non-Gaussian stable random variables play the role of normal distribution in the central limit theorem, for normalized sums of random variables with infinite variance. The lack of analytic formula for density and distribution functions of stable random variables has been a major drawback to the use of stable distributions, also in the case of inference in Bayesian framework. Buckle introduced priors for the parameters of stable random variables to obtain an analytic form of posterior distribution. However, many researchers tried to solve the problem, through the Markov chain Monte Carlo methods, e.g. [8] and their references. In this paper a new class of heavy-tailed distribution is introduced, called skewed stable. This class has two main advantages: It has many inferential advantages, since it is a member of exponential family, so the Bayesian inference can be drawn similar to the exponential family of distributions and modelling skew data with stable distributions is dominated by this family. Finally, Bayesian inference for skewed stable arc compared to the stable distributions through a few simulations study.

  8. Can orangutans (Pongo abelii) infer tool functionality?

    PubMed

    Mulcahy, Nicholas J; Schubiger, Michèle N

    2014-05-01

    It is debatable whether apes can reason about the unobservable properties of tools. We tested orangutans for this ability with a range of tool tasks that they could solve by using observational cues to infer tool functionality. In experiment 1, subjects successfully chose an unbroken tool over a broken one when each tool's middle section was hidden. This prevented seeing which tool was functional but it could be inferred by noting the tools' visible ends that were either disjointed (broken tool) or aligned (unbroken tool). We investigated whether success in experiment 1 was best explained by inferential reasoning or by having a preference per se for a hidden tool with an aligned configuration. We conducted a similar task to experiment 1 and included a functional bent tool that could be arranged to have the same disjointed configuration as the broken tool. The results suggested that subjects had a preference per se for the aligned tool by choosing it regardless of whether it was paired with the broken tool or the functional bent tool. However, further experiments with the bent tool task suggested this preference was a result of additional demands of having to attend to and remember the properties of the tools from the beginning of the task. In our last experiment, we removed these task demands and found evidence that subjects could infer the functionality of a broken tool and an unbroken tool that both looked identical at the time of choice.

  9. Inference of magnetic fields in inhomogeneous prominences

    NASA Astrophysics Data System (ADS)

    Milić, I.; Faurobert, M.; Atanacković, O.

    2017-01-01

    Context. Most of the quantitative information about the magnetic field vector in solar prominences comes from the analysis of the Hanle effect acting on lines formed by scattering. As these lines can be of non-negligible optical thickness, it is of interest to study the line formation process further. Aims: We investigate the multidimensional effects on the interpretation of spectropolarimetric observations, particularly on the inference of the magnetic field vector. We do this by analyzing the differences between multidimensional models, which involve fully self-consistent radiative transfer computations in the presence of spatial inhomogeneities and velocity fields, and those which rely on simple one-dimensional geometry. Methods: We study the formation of a prototype line in ad hoc inhomogeneous, isothermal 2D prominence models. We solve the NLTE polarized line formation problem in the presence of a large-scale oriented magnetic field. The resulting polarized line profiles are then interpreted (i.e. inverted) assuming a simple 1D slab model. Results: We find that differences between input and the inferred magnetic field vector are non-negligible. Namely, we almost universally find that the inferred field is weaker and more horizontal than the input field. Conclusions: Spatial inhomogeneities and radiative transfer have a strong effect on scattering line polarization in the optically thick lines. In real-life situations, ignoring these effects could lead to a serious misinterpretation of spectropolarimetric observations of chromospheric objects such as prominences.

  10. Combinatorics of distance-based tree inference

    PubMed Central

    Pardi, Fabio; Gascuel, Olivier

    2012-01-01

    Several popular methods for phylogenetic inference (or hierarchical clustering) are based on a matrix of pairwise distances between taxa (or any kind of objects): The objective is to construct a tree with branch lengths so that the distances between the leaves in that tree are as close as possible to the input distances. If we hold the structure (topology) of the tree fixed, in some relevant cases (e.g., ordinary least squares) the optimal values for the branch lengths can be expressed using simple combinatorial formulae. Here we define a general form for these formulae and show that they all have two desirable properties: First, the common tree reconstruction approaches (least squares, minimum evolution), when used in combination with these formulae, are guaranteed to infer the correct tree when given enough data (consistency); second, the branch lengths of all the simple (nearest neighbor interchange) rearrangements of a tree can be calculated, optimally, in quadratic time in the size of the tree, thus allowing the efficient application of hill climbing heuristics. The study presented here is a continuation of that by Mihaescu and Pachter on branch length estimation [Mihaescu R, Pachter L (2008) Proc Natl Acad Sci USA 105:13206–13211]. The focus here is on the inference of the tree itself and on providing a basis for novel algorithms to reconstruct trees from distances. PMID:23012403

  11. Combinatorics of distance-based tree inference.

    PubMed

    Pardi, Fabio; Gascuel, Olivier

    2012-10-09

    Several popular methods for phylogenetic inference (or hierarchical clustering) are based on a matrix of pairwise distances between taxa (or any kind of objects): The objective is to construct a tree with branch lengths so that the distances between the leaves in that tree are as close as possible to the input distances. If we hold the structure (topology) of the tree fixed, in some relevant cases (e.g., ordinary least squares) the optimal values for the branch lengths can be expressed using simple combinatorial formulae. Here we define a general form for these formulae and show that they all have two desirable properties: First, the common tree reconstruction approaches (least squares, minimum evolution), when used in combination with these formulae, are guaranteed to infer the correct tree when given enough data (consistency); second, the branch lengths of all the simple (nearest neighbor interchange) rearrangements of a tree can be calculated, optimally, in quadratic time in the size of the tree, thus allowing the efficient application of hill climbing heuristics. The study presented here is a continuation of that by Mihaescu and Pachter on branch length estimation [Mihaescu R, Pachter L (2008) Proc Natl Acad Sci USA 105:13206-13211]. The focus here is on the inference of the tree itself and on providing a basis for novel algorithms to reconstruct trees from distances.

  12. Inferring Pedigree Graphs from Genetic Distances

    NASA Astrophysics Data System (ADS)

    Tamura, Takeyuki; Ito, Hiro

    In this paper, we study a problem of inferring blood relationships which satisfy a given matrix of genetic distances between all pairs of n nodes. Blood relationships are represented by our proposed graph class, which is called a pedigree graph. A pedigree graph is a directed acyclic graph in which the maximum indegree is at most two. We show that the number of pedigree graphs which satisfy the condition of given genetic distances may be exponential, but they can be represented by one directed acyclic graph with n nodes. Moreover, an O(n3) time algorithm which solves the problem is also given. Although phylogenetic trees and phylogenetic networks are similar data structures to pedigree graphs, it seems that inferring methods for phylogenetic trees and networks cannot be applied to infer pedigree graphs since nodes of phylogenetic trees and networks represent species whereas nodes of pedigree graphs represent individuals. We also show an O(n2) time algorithm which detects a contradiction between a given pedigreee graph and distance matrix of genetic distances.

  13. Functional neuroanatomy of intuitive physical inference.

    PubMed

    Fischer, Jason; Mikhael, John G; Tenenbaum, Joshua B; Kanwisher, Nancy

    2016-08-23

    To engage with the world-to understand the scene in front of us, plan actions, and predict what will happen next-we must have an intuitive grasp of the world's physical structure and dynamics. How do the objects in front of us rest on and support each other, how much force would be required to move them, and how will they behave when they fall, roll, or collide? Despite the centrality of physical inferences in daily life, little is known about the brain mechanisms recruited to interpret the physical structure of a scene and predict how physical events will unfold. Here, in a series of fMRI experiments, we identified a set of cortical regions that are selectively engaged when people watch and predict the unfolding of physical events-a "physics engine" in the brain. These brain regions are selective to physical inferences relative to nonphysical but otherwise highly similar scenes and tasks. However, these regions are not exclusively engaged in physical inferences per se or, indeed, even in scene understanding; they overlap with the domain-general "multiple demand" system, especially the parts of that system involved in action planning and tool use, pointing to a close relationship between the cognitive and neural mechanisms involved in parsing the physical content of a scene and preparing an appropriate action.

  14. Inferring sparse networks for noisy transient processes

    NASA Astrophysics Data System (ADS)

    Tran, Hoang M.; Bukkapatnam, Satish T. S.

    2016-02-01

    Inferring causal structures of real world complex networks from measured time series signals remains an open issue. The current approaches are inadequate to discern between direct versus indirect influences (i.e., the presence or absence of a directed arc connecting two nodes) in the presence of noise, sparse interactions, as well as nonlinear and transient dynamics of real world processes. We report a sparse regression (referred to as the -min) approach with theoretical bounds on the constraints on the allowable perturbation to recover the network structure that guarantees sparsity and robustness to noise. We also introduce averaging and perturbation procedures to further enhance prediction scores (i.e., reduce inference errors), and the numerical stability of -min approach. Extensive investigations have been conducted with multiple benchmark simulated genetic regulatory network and Michaelis-Menten dynamics, as well as real world data sets from DREAM5 challenge. These investigations suggest that our approach can significantly improve, oftentimes by 5 orders of magnitude over the methods reported previously for inferring the structure of dynamic networks, such as Bayesian network, network deconvolution, silencing and modular response analysis methods based on optimizing for sparsity, transients, noise and high dimensionality issues.

  15. Functional neuroanatomy of intuitive physical inference

    PubMed Central

    Mikhael, John G.; Tenenbaum, Joshua B.; Kanwisher, Nancy

    2016-01-01

    To engage with the world—to understand the scene in front of us, plan actions, and predict what will happen next—we must have an intuitive grasp of the world’s physical structure and dynamics. How do the objects in front of us rest on and support each other, how much force would be required to move them, and how will they behave when they fall, roll, or collide? Despite the centrality of physical inferences