scholarly journals Scaling properties of gravity-driven sediments

1995 ◽  
Vol 2 (3/4) ◽  
pp. 178-185 ◽  
Author(s):  
D. H. Rothman ◽  
J. P. Grotzinger
Keyword(s):  
Critical Thickness ◽  
Sedimentary Basin ◽  
Scaling Law ◽  
Scaling Exponent ◽  
Power Law Distribution ◽  
Scaling Properties ◽  
Number Of Layers ◽  
Gravity Driven ◽  
Gravity Driven Flow ◽  
Open Question

Abstract. Recent field observations of the statistical distribution of turbidite and debris flow deposits are discussed. In some cases one finds a good fit over 1.5-2 orders of magnitude to the scaling law N(h) α h-B, where N(h) is the number of layers thicker than h. Observations show that the scaling exponent B varies widely from deposit to deposit, ranging from about 1/2 to 2. Moreover, one case is characterized by a sharp crossover in which B increases by a factor of two as h increases past a critical thickness. We propose that the variations in B, either regional or within the same deposit, are indicative of the geometry of the sedimentary basin and the rheological properties of the original gravity-driven flow. The origin of the power-law distribution remains an open question.

scholarly journals Intra-Urban Scaling Properties Examined by Automatically Extracted City Hotspots from Street Data and Nighttime Light Imagery

2021 ◽  
Vol 13 (7) ◽  
pp. 1322
Author(s):  
Ding Ma ◽  
Renzhong Guo ◽  
Ying Jing ◽  
Ye Zheng ◽  
Zhigang Zhao ◽  
...  
Keyword(s):  
Urban Form ◽  
Infrared Imaging ◽  
Spatial Clustering ◽  
Scaling Law ◽  
City Size ◽  
Power Law Distribution ◽  
Scaling Properties ◽  
Country Level ◽  
Nighttime Light ◽  
Urban Scaling

A country can be well-comprehended through its core cities. Similarly, we can learn about a city from its hotspots, as they manifest the concentration of urban infrastructures and human activities. Following this philosophy, this paper studies the intra-urban form and function from a complexity science perspective by exploring the power law distribution of hotspot sizes and related socio-economic attributes. To detect hotspots, we rely on spatial clustering of geospatial big data sets, including street data from OpenStreetMap platform and nighttime light (NTL) data from the visible infrared imaging radiometer suite (VIIRS) imagery. Unlike conventional spatial units, which are imposed by governments or authorities (such as census block), the delineation of hotspots is done in a totally bottom-up manner and, more importantly, can help us examine precisely the scaling pattern of urban morphological and functional aspects. This results in two types of urban hotspots—street-based and NTL-based hotspots—being generated across 20 major cities in China. We find that Zipf’s law of hotspot sizes (both types) holds remarkably well for each city, as do the city-size distributions at the country level, indicating a statistically self-similar structure of geographic space. We further find that the urban scaling law can be effectively detected when using NTL-based hotspots as basic units. Furthermore, the comparison between two types of hotspots enables us to gain in-depth insights of urban planning and urban economic development.

scholarly journals Buoyancy-driven dispersion in a layered porous rock

2015 ◽  
Vol 767 ◽  
pp. 226-239 ◽  
Author(s):  
Adrian Farcas ◽  
Andrew W. Woods
Keyword(s):  
Constant Pressure ◽  
Single Layer ◽  
Flow Speed ◽  
Longitudinal Dispersion ◽  
Longitudinal Distribution ◽  
Porous Rock ◽  
Pressure Source ◽  
Number Of Layers ◽  
Gravity Driven ◽  
Gravity Driven Flow

AbstractWe investigate the longitudinal dispersion of a passive tracer by a gravity-driven flow in a porous medium consisting of a series of independent horizontal layers connected to a constant pressure source. We show that in a formation of given vertical extent, the total flux is only weakly dependent on the number of layers, and is very similar to that in a single layer of the same total depth. However, although the flow speed in each layer is approximately uniform, the speed gradually increases with layer depth. As a result, if a pulse of tracer is released in the flow it will migrate more rapidly through the lower layers, leading to longitudinal dispersion of the tracer. Eventually, the location of the tracer in the different layers may become separated in space so that a sufficiently distant observation well would detect a series of discrete pulses of tracer rather than the original coherent input, as would occur in a single permeable layer. For a constant pressure source, at long times, the standard deviation of the longitudinal distribution of tracer asymptotes to a fraction of order 0.1 of the position of the centre of mass, depending on the number of layers and the overpressure of the source.

scholarly journals Synchronization and desynchronization in the Olami-Feder-Christensen earthquake model and potential implications for real seismicity

2011 ◽  
Vol 18 (5) ◽  
pp. 635-642 ◽  
Author(s):  
S. Hergarten ◽  
R. Krenn
Keyword(s):  
Power Law ◽  
Statistical Properties ◽  
Scaling Exponent ◽  
Power Law Distribution ◽  
Scaling Properties ◽  
Temporal Clustering ◽  
Self Organized ◽  
Earthquake Model ◽  
Self Organized Criticality ◽  
Large Earthquakes

Abstract. The Olami-Feder-Christensen model is probably the most studied model in the context of self-organized criticality and reproduces several statistical properties of real earthquakes. We investigate and explain synchronization and desynchronization of earthquakes in this model in the nonconservative regime and its relevance for the power-law distribution of the event sizes (Gutenberg-Richter law) and for temporal clustering of earthquakes. The power-law distribution emerges from synchronization, and its scaling exponent can be derived as τ = 1.775 from the scaling properties of the rupture areas' perimeter. In contrast, the occurrence of foreshocks and aftershocks according to Omori's law is closely related to desynchronization. This mechanism of foreshock and aftershock generation differs strongly from the widespread idea of spontaneous triggering and gives an idea why some even large earthquakes are not preceded by any foreshocks in nature.

EFFECT OF FLOCCULATING AGENTS ON DRAG IN GRAVITY-DRIVEN FLOW SYSTEMS

2017 ◽  
Vol 44 (4) ◽  
pp. 339-347
Author(s):  
M. K. S. V. Raghav ◽  
Ravi Teja ◽  
Chirravuri Subbarao
Keyword(s):  
Flow Systems ◽  
Gravity Driven ◽  
Gravity Driven Flow

Drag reduction using mixed solutions of hydrotrope and surfactant in gravity driven flow systems

2013 ◽  
Vol 8 (3) ◽  
pp. 22-27
Author(s):  
M. Venkata Ramana ◽  
◽  
Ch. V. Subbarao ◽  
P. V. Gopal singh ◽  
Krishna Prasad K.M.M ◽  
...  
Keyword(s):  
Drag Reduction ◽  
Mixed Solutions ◽  
Flow Systems ◽  
Gravity Driven ◽  
Gravity Driven Flow

scholarly journals Two-Dimensional Convection Induced by Gravity and Centrifugal Forces in a Rotating Porous Layer Far Away from the Axis of Rotation

1998 ◽  
Vol 4 (2) ◽  
pp. 73-90 ◽  
Author(s):  
Peter Vadasz ◽  
Saneshan Govender
Keyword(s):  
Rayleigh Number ◽  
Porous Layer ◽  
Temperature Fields ◽  
Wave Number ◽  
Marginal Stability ◽  
Two Dimensional ◽  
Wide Range ◽  
Gravity Driven ◽  
Gravity Driven Flow ◽  
The Stability

The stability and onset of two-dimensional convection in a rotating fluid saturated porous layer subject to gravity and centrifugal body forces is investigated analytically. The problem corresponding to a layer placed far away from the centre of rotation was identified as a distinct case and therefore justifying special attention. The stability of a basic gravity driven convection is analysed. The marginal stability criterion is established in terms of a critical centrifugal Rayleigh number and a critical wave number for different values of the gravity related Rayleigh number. For any given value of the gravity related Rayleigh number there is a transitional value of the wave number, beyond which the basic gravity driven flow is stable. The results provide the stability map for a wide range of values of the gravity related Rayleigh number, as well as the corresponding flow and temperature fields.

scholarly journals Modelling gravity-driven flow over uneven surfaces

2010 ◽  
Author(s):  
K. A. Ogden ◽  
S. J. D. D’Alessio ◽  
J. P. Pascal
Keyword(s):  
Gravity Driven ◽  
Gravity Driven Flow

scholarly journals Characterizing the Foreshock, Main Shock, and Aftershock Sequences of the Recent Major Earthquakes in Southern Alaska, 2016–2018

2020 ◽  
Vol 8 ◽  
Author(s):  
B. G. Bukchin ◽  
A. S. Fomochkina ◽  
V. G. Kossobokov ◽  
A. K. Nekrasova
Keyword(s):  
Control Parameter ◽  
Empirical Distribution ◽  
Scaling Law ◽  
Plate Boundary ◽  
Scaling Properties ◽  
Second Moments ◽  
The Pacific ◽  
Unified Scaling Law ◽  
Aftershock Sequences ◽  
Integral Estimation

For each of three major M ≥ 7.0 earthquakes (i.e., the January 24, 2016, M7.1 earthquake 86 km E of Old Iliamna; the January 23, 2018, M7.9 earthquake 280 km SE of Kodiak; and the November 30, 2018, M7.1 earthquake 14 km NNW of Anchorage, Alaska), the study considers characterization of the foreshock and aftershock sequences in terms of their variations and scaling properties, including the behavior of the control parameter η of the unified scaling law for earthquakes (USLE), along with a detailed analysis of the surface wave records for reconstruction of the source in the approximation of the second moments of the stress glut tensor to obtain integral estimation of its length, orientation, and development over time. The three major earthquakes at 600 km around Anchorage are, in fact, very different due to apparent complexity of earthquake flow dynamics in the orogenic corner of the Pacific and North America plate boundary. The USLE generalizes the classic Gutenberg-Richter relationship taking into account the self-similar scaling of the empirical distribution of earthquake epicenters. The study confirms the existence of the long-term periods of regional stability of the USLE control parameter that are interrupted by mid- or even short-term bursts of activity associated with major catastrophic events.

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