scholarly journals A harmonised instrumental earthquake catalogue for Iceland and the northern Mid-Atlantic Ridge

2021 ◽  
Vol 21 (7) ◽  
pp. 2197-2214
Author(s):  
Kristján Jónasson ◽  
Bjarni Bessason ◽  
Ásdís Helgadóttir ◽  
Páll Einarsson ◽  
Gunnar B. Guðmundsson ◽  
...  
Keyword(s):  
Body Wave ◽  
Historical Earthquakes ◽  
The Body ◽  
Plate Motion ◽  
Hazard Mapping ◽  
Local Data ◽  
Scientific Publications ◽  
Uncertainty Estimates ◽  
Completeness Magnitude ◽  
Mid Atlantic Ridge

Abstract. A comprehensive catalogue of historical earthquakes, with accurate epicentres and harmonised magnitudes is a crucial resource for seismic hazard mapping. Here we update and combine catalogues from several sources to compile a catalogue of earthquakes in and near Iceland, in the years 1900–2019. In particular the epicentres are based on local information, whereas the magnitudes are based on teleseismic observations, primarily from international online catalogues. The most reliable epicentre information comes from the catalogue of the Icelandic Meteorological Office, but this is complemented with information from several technical reports, scientific publications, and newspaper articles. The catalogue contains 1281 moment magnitude (Mw) ≥4 events, and the estimated completeness magnitude is Mw 5.5 in the first years, going down to Mw 4.5 for recent years. The largest magnitude is Mw 7.0. Such merging of local data and teleseismic catalogues has not been done before for Icelandic earthquakes, and the result is an earthquake map with much more accurate locations than earlier maps. The catalogue also lists 5640 additional earthquakes on the Mid-Atlantic Ridge, north of 43∘, with both epicentres and magnitudes determined teleseismically. When moment magnitudes are not available, proxy Mw values are computed using χ2 regression, normally on the surface-wave magnitude but exceptionally on the body-wave magnitude. Magnitudes of Mw≥4.5 have associated uncertainty estimates. The actual combined seismic moment released in the Icelandic earthquakes is found to be consistent with the moment estimated using a simple plate motion model, indicating that the seismic activity of the catalogue period might be typical of any 120-year time span. The catalogue is named ICEL-NMAR, and it is available online at http://data.mendeley.com (last access: 19 July 2021).

scholarly journals A Harmonised Instrumental Earthquake Catalogue for Iceland and the Northern Mid-Atlantic Ridge

2021 ◽  
Author(s):  
Kristján Jónasson ◽  
Bjarni Bessason ◽  
Ásdís Helgadóttir ◽  
Páll Einarsson ◽  
Gunnar B. Gudmundsson ◽  
...  
Keyword(s):  
Historical Earthquakes ◽  
Plate Motion ◽  
Hazard Mapping ◽  
Scientific Publications ◽  
Teleseismic Data ◽  
Uncertainty Estimates ◽  
Completeness Magnitude ◽  
Mid Atlantic Ridge ◽  
On Line ◽  
The Moment

Abstract. A comprehensive catalogue of historical earthquakes, with accurate epicentres and homogenised magnitudes is a crucial resource for seismic hazard mapping. Here we update and combine catalogues from several sources to compile a catalogue of earthquakes in and near Iceland, in the years 1900–2019. In particular the epicentres are based on local information, whereas the magnitudes are based on teleseismic observations, primarily from international on-line catalogues. The most reliable epicentre information comes from the catalogue of the Icelandic Meteorological Office, but this is complemented with information from several technical reports, scientific publications, newspaper articles, and modified by some expert judgement. The catalogue contains 1272 MW ≥ 4 events and the estimated completeness magnitude is W 5.5 in the first years, going down to MW 4.5 for recent years. The largest magnitude is MW 7.01. Such melting of local and teleseismic data has not been done before for Icelandic earthquakes, and the result is an earthquake map with no obviously mislocated events. The catalogue also lists additional 5654 earthquakes on the Mid-Atlantic Ridge, north of 43°, with both epicentres and magnitudes determined teleseismically. When moment magnitudes are not available, proxy MW values are computed with χ2-regression, normally on MS, but exceptionally on mb. All the presented magnitudes have associated uncertainty estimates. The actual combined seismic moment released in the Icelandic earthquakes is found to be consistent with the moment estimated using a simple plate motion model. The catalogue is named ICEL-NMAR and it is available online at http://dx.doi.org/10.17632/7zh6xg22cv.1.

Estimates of magnitudes and short-period wave attenuation of Chinese earthquakes from Modified Mercalli intensity data

1984 ◽  
Vol 74 (3) ◽  
pp. 957-968
Author(s):  
Peishan Chen ◽  
Otto W. Nuttli
Keyword(s):  
Wave Attenuation ◽  
Body Wave ◽  
Empirical Relation ◽  
Historical Earthquakes ◽  
The Body ◽  
Intensity Data ◽  
Mountainous Regions ◽  
Short Period ◽  
Recent Earthquakes ◽  
Period Wave

Abstract Intensity data for Chinese earthquakes are used to estimate the body-wave magnitude, mb, of selected historical earthquakes and to estimate Q0, the 1-sec period Q value of Lg waves for various geographical areas of China. In order to derive the necessary empirical relation between the intensity distribution and mb, data are used from recent earthquakes, for which instrumentally obtained mb values as well as isoseismal maps are available. Average Qo values are approximately 175 for the mountainous regions of southwest China, 550 for southeastern China, and 150 for Taiwan. These values agree qualitatively with those obtained by Evernden (1983) and Chen et al. (1983), who utilized a different method of analysis of the intensity data

scholarly journals Teleseismic analysis of the 1980 Mammoth Lakes earthquake sequence

1982 ◽  
Vol 72 (4) ◽  
pp. 1093-1109
Author(s):  
Jeffrey W. Given ◽  
Terry C. Wallace ◽  
Hiroo Kanamori
Keyword(s):  
Surface Wave ◽  
Sierra Nevada ◽  
Body Wave ◽  
The Body ◽  
Body Waves ◽  
Earthquake Sequence ◽  
Local Data ◽  
Fault Plane Solutions ◽  
Principal Axes ◽  
Mammoth Lakes

abstract The source mechanisms of the three largest events of the 1980 Mammoth Lakes earthquake sequence have been determined using surface waves recorded on the global digital seismograph network and the long-period body waves recorded on the WWSSN network. Although the fault-plane solutions from local data (Cramer and Toppozada, 1980; Ryall and Ryall, 1981) suggest nearly pure left-lateral strike-slip on north-south planes, the teleseismic waveforms require a mechanism with oblique slip. The first event (25 May 1980, 16h 33m 44s) has a mechanism with a strike of N12°E, dip of 50°E, and a rake of −35°. The second event (27 May 19h 44m 51s) has a mechanism with a strike of N15°E, dip of 50°, and a slip of −11°. The third event (27 May, 14h 50m 57s) has a mechanism with a strike of N22°E, dip of 50°, and a rake of −28°. The first event is the largest and has a moment of 2.9 × 1025 dyne-cm. The second and third events have moments of 1.3 and 1.1 × 1025 dyne-cm, respectively. The body- and surface-wave moments for the first and third events agree closely while for the second event the body-wave moment (approximately 0.6 × 1025 dyne-cm) is almost a factor of 3 smaller than the surface-wave moment. The principal axes of extension of all three events is in the approximate direction of N65°E which agrees with the structural trends apparent along the eastern front of the Sierra Nevada.

Predicting the citation and impact factor of terms for scientific publications using machine learning algorithms

2020 ◽  
Author(s):  
Aleksey Klokov ◽  
Evgenii Slobodyuk ◽  
Michael Charnine
Keyword(s):  
Machine Learning ◽  
Semantic Processing ◽  
The Body ◽  
Machine Learning Algorithms ◽  
Scientific Publications ◽  
Text Data ◽  
Semantic Relationships ◽  
Subject Areas ◽  
The Subject ◽  
Scientific Environment

The object of the research when writing the work was the body of text data collected together with the scientific advisor and the algorithms for processing the natural language of analysis. The stream of hypotheses has been tested against computer science scientific publications through a series of simulation experiments described in this dissertation. The subject of the research is algorithms and the results of the algorithms, aimed at predicting promising topics and terms that appear in the course of time in the scientific environment. The result of this work is a set of machine learning models, with the help of which experiments were carried out to identify promising terms and semantic relationships in the text corpus. The resulting models can be used for semantic processing and analysis of other subject areas.

The Powers of Testosterone: Obscuring Race and Regional Bias in the Regulation of Women Athletes

2019 ◽  
Vol 25 (1-2019) ◽  
pp. 83-120
Author(s):  
Katrina Karkazis ◽  
Rebecca M. Jordan-Young
Keyword(s):  
Women Athletes ◽  
Women Of Color ◽  
Media Coverage ◽  
The Body ◽  
Feminist Studies ◽  
Sport Organizations ◽  
Scientific Publications ◽  
Cultural Symbol ◽  
Western Modernity ◽  
Fair Competition

Using strategies from critical race studies and feminist studies of science, medicine, and the body, we examine the covert operation of race and region in a regulation restricting the natural levels of testosterone in women athletes. Sport organizations claim the rule promotes fair competition and benefits the health of women athletes. Intersectional and postcolonial analyses have shown that "gender challenges" of specific women athletes engage racialized judgments about sex atypicality that emerged in the context of Western colonialism and are at the heart of Western modernity. Here, we introduce the concept of "T talk" to refer to the web of direct claims and indirect associations that circulate around testosterone as a material substance and a multivalent cultural symbol. In the case we discuss, T talk naturalizes the idea of sport as a masculine domain while deflecting attention from the racial politics of intrasex competition. Using regulation documents, scientific publications, media coverage, in-depth interviews, and sport officials’ public presentations, we show how this supposedly neutral and scientific regulation targets women of color from the Global South. Contrary to claims that the rule is beneficent, both racialization and medically-authorized harms are inherent to the regulation.

ANALGESIC AND ANTI-INFLAMMATORY EFFECTS OF ACETYLSALICYLIC ACID: PHYSIOLOGICAL MECHANISMS

2020 ◽  
Vol 6(72) (1) ◽  
pp. 197-219
Author(s):  
I. V. Cheretaev ◽  
D. R. Khusainov ◽  
E. N. Chuyan ◽  
M. Yu. Ravaeva ◽  
A. N. Gusev ◽  
...  
Keyword(s):  
Acetylsalicylic Acid ◽  
Physiological Mechanism ◽  
The Body ◽  
Physiological Mechanisms ◽  
Scientific Publications ◽  
Thermal Pain ◽  
Order Of Magnitude ◽  
Anti Inflammatory ◽  
Number Of Publications ◽  
Electrical Stimuli

The purpose of the review is to summarize current literature data and the results of our own research on the analgesic and anti-inflammatory effects of acetylsalicylic acid, as well as the physiological mechanisms underlying them. This acid is the most studied reference representative of salicylates, which is convenient to consider the physiological effects characteristic in general for this group of chemical and medicinal products. Acetylsalicylic acid has analgesic properties against thermal pain and pain caused by electrical stimuli, as well as a pronounced anti-inflammatory effect. The realization of these properties depends on the peculiarities of aspirin metabolism in the body, ion and synaptic mechanisms for controlling the functional state of the cell, neurotransmitter systems of the сentral nervous system, and mechanisms of peripheral and сentral analgesia. Analgesic properties of acetylsalicylic acid founded not only in normal, but also in ultra-small doses. Various physical and especially chemical factors significantly change their effects. This increases the interest in studying the analgesic activity of salicylates and their physiological mechanisms, since such studies can serve as a basis for creating new non-steroidal anti-inflammatory drugs with low toxicity and high safety for patients, and improve the strategy of their practical use. Currently, the most detailed study of the physiological mechanism of analgesic and anti-inflammatory action of aspirin and its main metabolite – salicylic acid. However, it should be note that despite the abundance of existing data obtained in scientific studies of the effects of aspirin and its practical use, there are a number of unexplained aspects of the action of this drug, the mechanism of which has not yet been deciphered. The continuing interest in the effects and mechanisms of action of this drug and in connection with the expansion of its use evidenced by a consistently high number of scientific publications on aspirin in the most famous foreign and domestic publications. At the same time, the number of publications about aspirin is an order of magnitude higher than about any other drug known to humanity.

Fractures in the northern plains, stream patterns, and the midcontinent stress field

1987 ◽  
Vol 24 (6) ◽  
pp. 1086-1097 ◽  
Author(s):  
Mel R. Stauffer ◽  
Don J. Gendzwill
Keyword(s):  
Stress Field ◽  
Horizontal Stress ◽  
The Body ◽  
North American Plate ◽  
Plate Motion ◽  
Viscous Drag ◽  
Near Surface ◽  
The North ◽  
Elastic Rebound ◽  
Western North Dakota

Fractures in Late Cretaceous to Late Pleistocene sediments in Saskatchewan, eastern Montana, and western North Dakota form two vertical, orthogonal sets trending northeast–southwest and northwest–southeast. The pattern is consistent, regardless of rock type or age (except for concretionary sandstone). Both sets appear to be extensional in origin and are similar in character to joints in Alberta. Modem stream valleys also trend in the same two dominant directions and may be controlled by the underlying fractures.Elevation variations on the sub-Mannville (Early Cretaceous) unconformity form a rectilinear pattern also parallel to the fracture sets, suggesting that fracturing was initiated at least as early as Late Jurassic. It may have begun earlier, but there are insufficient data at present to extend the time of initiation.We interpret the fractures as the result of vertical uplift together with plate motion: the westward drift of North America. The northeast–southwest-directed maximum principal horizontal stress of the midcontinent stress field is generated by viscous drag effects between the North American plate and the mantle. Vertical uplift, erosion, or both together produce a horizontal tensile state in near-surface materials, and with the addition of a directed horizontal stress through plate motion, vertical tension cracks are generated parallel to that horizontal stress (northeast–southwest). Nearly instantaneous elastic rebound results in the production of second-order joints (northwest–southeast) perpendicular to the first. In this manner, the body of rock is being subjected with time to complex alternation of northeast–southwest and northwest–southeast horizontal stresses, resulting in the continuous and contemporaneous production of two perpendicular extensional joint sets.

Focal mechanism and source depth of earthquakes from body- and surface-wave data

1971 ◽  
Vol 61 (5) ◽  
pp. 1369-1379 ◽  
Author(s):  
Nezihi Canitez ◽  
M. Nafi Toksöz
Keyword(s):  
Surface Wave ◽  
Body Wave ◽  
Source Parameters ◽  
Focal Depth ◽  
Spectral Ratio ◽  
The Body ◽  
Spectral Ratios ◽  
Motion Data ◽  
Wave Data ◽  
Surface Wave Data

abstract The determination of focal depth and other source parameters by the use of first-motion data and surface-wave spectra is investigated. It is shown that the spectral ratio of Love to Rayleigh waves (L/R) is sensitive to all source parameters. The azimuthal variation of the L/R spectral ratios can be used to check the fault-plane solution as well as for focal depth determinations. Medium response, attenuation, and source finiteness seriously affect the absolute spectra and introduce uncertainty into the focal depth determinations. These effects are nearly canceled out when L/R amplitude ratios are used. Thus, the preferred procedure for source mechanism studies of shallow earthquakes is to use jointly the body-wave data, absolute spectra of surface waves, and the Love/Rayleigh spectral ratios. With this procedure, focal depths can be determined to an accuracy of a few kilometers.

Preliminary body-wave analysis of the St. Elias, Alaska earthquake of February 28, 1979

1980 ◽  
Vol 70 (2) ◽  
pp. 419-436
Author(s):  
John Boatwright
Keyword(s):  
New York ◽  
Body Wave ◽  
The Body ◽  
Rupture Velocity ◽  
Wave Analysis ◽  
S Waves ◽  
Initial Event ◽  
Whole Space ◽  
A New Technique ◽  
Alaska Earthquake

abstract Employing a new technique for the body-wave analysis of shallow-focus earthquakes, we have made a preliminary analysis of the St. Elias, Alaska earthquake of February 28, 1979, using five long-period P and S waves recorded at three WWSSN stations and at Palisades, New York. Using a well determined focal mechanism and an average source depth of ≈ 11 km, the interference of the depth phases (i.e., pP and sP, or sS) has been deconvolved from the recorded pulse shapes to obtain velocity and displacement pulse shapes as they would appear if the earthquake had occurred within an infinite medium. These “approximate whole space” pulse shapes indicate that the rupture contained three distinct subevents as well as a small initial event which preceded this subevent sequence by about 7 sec. From the pulse rise times of the subevents, their rupture lengths are estimated as 12, 27, and 17 km, assuming that the subevent rupture velocity was 3 km/sec. Overall, the earthquake ruptured ≈ 60 km to the southeast with an average rupture velocity of 2.2 km/sec. The cumulative body-wave moment for the whole event, 1.2 × 1027 dyne-cm, is substantially smaller than the surface-wave moments reported by Lahr et al. (1979) of 5 × 1027 dyne-cm. The moments of the subevents are estimated to be 0.6, 3.2, and 7.5 × 1026 dyne-cm, respectively.

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