Counting statistics of f −β fluctuations: a new method for analysis of earthquake data     

H. R. Bittner  P. Tosi  C. Braun  M. Meesmann  K. -D. Kniffki 《International Journal of Earth Sciences》1996,85(1):110-115

In a variety of biological and physical phenomena, temporal fluctuations are found, which are not explainable as consequences of statistically independent random events. If these fluctuations are characterized by a power spectrum density S(f) decaying as f ^– at low frequencies, this behaviour is called 1/f noise.Counting statistics applied to earthquake activity data leads to three time scales with different characteristics, represented by the exponent : at interval lengths less than 1 h, the shocks are randomly distributed as in a Poisson process. For medium time intervals (1 day to 3 months), the exponent 1 + is larger (1.4 for M ₀=3), but approaches unity for higher threshold magnitudes M ₀. In longer time ranges the exponent assumes values near 1.55, however, with increasing statistical variation at higher M ₀, due to lower counts.The temporal sequence is different from white noise; thus, it might be fruitful to apply neural network algorithms, because this method allows predictions in some other cases with similar characteristics.  相似文献   

Aquifer-induced Seismicity in the Central Apennines (Italy)     

F. Bella  P. F. Biagi  M. Caputo  E. Cozzi  G. Della Monica  A. Ermini  W. Plastino  V. Sgrigna 《Pure and Applied Geophysics》1998,153(1):179-194

—The Gran Sasso chain (Central Apennines, Italy) contains one of the largest aquifers of Central Italy. From 1970–1986 the massif was tunnelled through in order to build up a highway and an international underground laboratory for nuclear physics research. These works have strongly modified the hydrogeological situation of the chain, as shown by the decrease in flow rate that occurred in many springs located at the border of the carbonatic structure, along the boundary between the permeable limestone of the massif and the surrounding aquicludes. The analysis of the seismicity (M≥ 3.0) that occurred in the Gran Sasso area from 1956 to 1995 suggests that after the tunnelling works both the number of earthquakes has increased and epicenters have migrated, gathering at the northwestern border zone. The foremost events which occurred in this zone in recent years took place on May 5, 1992 (M = 3.1), August 25, 1992 (M = 3.9) and March 13, 1994 (M = 3.5). The flow rate data of four springs and water level data of an underground karst pool located at the border of the carbonatic structure of the massif show clear anomalies before the occurrence of the quoted earthquakes. Regardless, these anomalies can be explained by the rapid melting of the thick mantle of snow on the Gran Sasso chain, due to sudden increases of mean temperatures. In this paper we present and discuss the possibility that the quoted earthquakes are induced by the irregular variations of the Gran Sasso aquifer, evidenced by the quoted anomalies in the flow rate and water level.  相似文献   

The Juiz De Fora Granulite Complex of the Central Ribeira Belt, SE Brazil: A Paleoproterozoic Crustal Segment Thrust During the Pan-African Orogeny     

Monica Heilbron  Beatriz Paschoal Duarte  Jos Renato Nogueira 《Gondwana Research》1998,1(3-4):373-381

The granulites of the Juiz de Fora complex occur within thick basement thrust slices associated with the Pan-African shortening process in the central segment of the Ribeira belt. Five lithological units of the Intermediate tectonic domain of the belt can be identified on the basis of detailed geological mapping: a) orthogranulites, b) orthogneisses; c) kinzigite; d) intrusive garnet charnockite and e) amphibolite facies metasediments of probable Meso to Neoproterozoic age, correlated to the cover of the belt. Petrological data indicate high temperatures and intermediate to low lithostatic pressure conditions for the Paleoproterozoic granulite facies metamorphism. Textures and CO₂-rich fluid inclusions are probably related to an IBC path. Geochemical data do not show relevant compositional change as a result of the granulite metamorphism. Two calc-alkaline suites and tholeiitic to alkaline basic rocks can be related to compressional and extensional settings, respectively. The overall composition of the granulites, the lack of substantial LILE depletion as well as the composition of the fluid inclusion points to granulitization process driven by CO₂-rich fluids. Orthogranulites gave rise to banded gneisses as a result of the Pan-African retrograde metamorphism and intense deformation. The U and Th depletion detected in few rocks is possibly related with the hydrated conditions of the retrograde reactions.  相似文献   

Limitations of an Eddy-Covariance System in Measuring Low Ammonia Fluxes     

Ferrara  Rossana Monica  Di Tommasi  Paul  Famulari  Daniela  Rana  Gianfranco 《Boundary-Layer Meteorology》2021,180(1):173-186

Green manuring of legume crops can improve soil fertility and sustainability. To evaluate its agronomic and environmental effectiveness, gaseous losses of ammonia (NH₃) in the surface layer need to be quantified by direct measurements in the field. However, the application of the eddy-covariance technique to atmospheric NH₃ is challenging: its high reactivity, water solubility, and low background concentrations all hinder the response time of closed-path sensors for fast measurements of NH₃ concentration. Ammonia emissions following green manuring were measured for 21 days using a flux system equipped with a fast-pulsed quantum-cascade tunable-infrared-laser spectrometer. The noisy cross-covariance function for this configuration indicates flux measurements are close to the limit of detection; the low signal-to-noise ratio further increases the uncertainties, introducing a mirroring effect on the fluxes, which results in the rapid alternation between emission and deposition, within the limit of detection (around 13 and 20 ng m^?2 s^?1, at the 95 and 99% confidence limits, respectively). An evaluation of the measurement errors is presented, focussing on three technical aspects of the eddy-covariance system: (1) time lag, (2) random error, and (3) limit of detection. The NH₃ fluxes measured by the spectrometer are close to its limit of detection, with a random error of the same order as the flux.

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Interaction between Climate Changes, Eustacy and Land Subsidence in the North Adriatic Region, Italy   总被引：4，自引：0，他引：4  

Laura Carbognin  Luigi Tosi 《Marine Ecology》2002,23(S1):38-50

Abstract. The North Adriatic coastal area has experienced a serious relative sea level rise whose main component is land subsidence. Geological regional subsidence is ascribable to compaction and to deformation of substratum. Anthropogenic subsidence, which is due to ground fluid removal, has been severe in the second half of the 19th century, reaching values in meters. It is without doubt the main factor responsible for the instability of the entire coastal ecosystem. Widespread retreat of shoreline, seawater invasion, decay of vegetation, changes in the habitat of the flora and fauna have occurred. Sea level rise alone is linked to climate changes, which exhibit fluctuations of the order of a few hundred years; here, cold-wet periods alternated with warm-dry periods and, within them, shorter cold-wet and hot-dry cycles lasting for decades also alternated.  相似文献   

Finding spatial outliers in collective mobility patterns coupled with social ties     

Monica Wachowicz  Tianyu Liu 《International journal of geographical information science》2016,30(9):1806-1831

ABSTRACT

Currently the increase in the variety and volume of data sources is demanding new data analytical workflows for exploring them concurrently, especially if the goal is to detect spatial outliers. In this paper, we propose a data analytical workflow for exploring Call Detail Records in conjunction with geotagged tweets. The aim was to investigate how massive data point observations can be analyzed to detect spatial outliers in collective mobility patterns that are coupled with social ties. This workflow consists of analytical tasks that are developed based on the a-priori assumption of two isometric spaces where Natural Language Processing techniques are used to find spatial clusters from geotagged tweets in a Social Space which are later used to aggregate the Call Detail Records generated by antennas located in the Mobility Space. The dynamic weighted centroids that are given by the mean location of the number of calls per hour of all antennas that belong to a particular cluster are used to compute Standard Deviation Ellipses. The longer the period of time a weighted centroid stays outside of the 99.7% probability region of an ellipse, the highest the likelihood that they are spatial outliers. The workflow was implemented for the city of Dakar in Senegal. The results indicate that the further the hourly weighted centroids are skewed from the normal mean of an ellipse, the stronger the influence of a cluster is in finding spatial outliers. Furthermore, the longer the period of time the outliers stays outside of the 99.7% probability region of an ellipse, the highest the likelihood that the outliers are genuine and can be associated to extraordinary events such as natural disasters and national holidays.  相似文献   

Polyphase metamorphism in the eastern Carnic Alps (N Italy–S Austria): clay minerals and conodont Colour Alteration Index evidence     

Covadonga Brime  Maria Cristina Perri  Monica Pondrelli  Claudia Spalletta  Corrado Venturini 《International Journal of Earth Sciences》2008,97(6):1213-1229

Thermal evolution of the Palaeozoic–Triassic sequences of the Carnic Alps has been characterized by b cell dimension and Kübler Index (illite “crystallinity”) of K-white micas (KI), árkai Index (AI) of chlorites, clay mineral assemblages and conodont Colour Alteration Index (CAI). Data indicate at least two metamorphic events, Variscan and Alpine. In the older event high anchizonal conditions predominated although epizonal conditions were reached over wide areas. It was characterized by low-intermediate pressure facies. The thermal peak was mainly due to an extensional regime during the Bashkirian. A younger thermal overprint generated by Alpine orogeny was of lower grade, reaching high diagenetic–anchizonal conditions characterized by high-pressure facies. Inverted metamorphic patterns are associated with middle to late Miocene thrusting. Hydrothermal alteration in the northern part of the region can be linked with emplacement of Oligocene plutons and high heat flow along the Periadratic lineament. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

Experiments in scientific computation on the PlayStation 3     

Erik O. D. Sevre  Monica D. Christiansen  Matt Broten  Shuo M. Wang  David A. Yuen 《Visual Geosciences》2008,13(1):125-132

The Sony PlayStation 3 (PS3) offers the computational power of a parallel processor at low cost, which makes it a great starter unit for development in parallel programming. To explore the capabilities of the unit, we took a simple ray tracing program and extended it to render triangulated height field data across the PS3’s 6 synergistic processing units (SPUs). We also implemented the heat averaging equation as a precursor to CFD analysis on the PS3. In our studies, we found the Cell engine in the PS3 to be a powerful machine, however great care must be taken while developing because its unique platform calls for many levels of optimization to ensure efficiency. For insight on early work done on modern stream computing and GPU processing look up the Merrimac project and Pat Hanrahan.  相似文献   

REDD+ politics in the media: a case from Nepal     

Dil B. Khatri  Thuy Thu Pham  Monica Di Gregorio  Rahul Karki  Naya S. Paudel  Maria Brockhaus  Ramesh Bhushal 《Climatic change》2016,138(1-2):309-323

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Moving consensus and managing expectations: media and REDD+ in Indonesia     

Tim Cronin  Levania Santoso  Monica Di Gregorio  Maria Brockhaus  Sofi Mardiah  Efrian Muharrom 《Climatic change》2016,137(1-2):57-70

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