Variation of source properties: The Inangahua, New Zealand, aftershocks of 1968

1975 ◽  
Vol 65 (1) ◽  
pp. 261-276
Author(s):  
S. J. Gibowicz
Keyword(s):  
Seismic Moment ◽  
Source Parameters ◽  
Aftershock Sequence ◽  
Suitable Parameter ◽  
The Moment ◽  
Earthquake Sequences ◽  
Source Dimension ◽  
The Relationship ◽  
Frequency Magnitude

abstract A theoretical relationship between seismic moment and local magnitude ML is derived from the relationship between magnitude ML and source dimension given by Randall (1973). For a circular fault of radius smaller than about 0.5 km, the magnitude ML is proportional to the logarithm of the seismic moment Mo, and these values alone cannot specify other source parameters. For greater radii the values of Mo and ML define Brune's (1970) far-field spectrum and in these cases other source characteristics can be readily obtained. The seismic moment can be estimated from the long-period amplitudes, and therefore the moment-magnitude relation provides a convenient method for determination of the source properties. The relationship between the logarithm of the various source parameters and seismic moment is considered for a number of regions and earthquake sequences. It appears to be of linear form and, furthermore, it seems that the same slope coefficient can be used in different regions. Source properties show regional differences, and the most suitable parameter to describe these differences is the average displacement. Besides the regional variations, there seems to be a time variation of source properties. This is the case for the Inangahua aftershock sequence, during which the variation of the displacement residuals correlates with the variation of the coefficient b, which defines the frequency-magnitude relation.

Aftershock Analysis of the 2018 Mw 7.1 Anchorage, Alaska, Earthquake: Relocations and Regional Moment Tensors

2019 ◽  
Vol 91 (1) ◽  
pp. 114-125 ◽  
Author(s):  
Natalia A. Ruppert ◽  
Avinash Nayak ◽  
Clifford Thurber ◽  
Cole Richards
Keyword(s):  
Moment Tensor ◽  
Hanging Wall ◽  
Velocity Model ◽  
Aftershock Sequence ◽  
Fault Rupture ◽  
Moment Tensors ◽  
3D Velocity Model ◽  
The Moment ◽  
The Relationship ◽  
Alaska Earthquake

Abstract The 30 November 2018 magnitude 7.1 Anchorage earthquake occurred as a result of normal faulting within the lithosphere of subducted Yakutat slab. It was followed by a vigorous aftershock sequence with over 10,000 aftershocks reported through the end of July 2019. The Alaska Earthquake Center produced a reviewed aftershock catalog with a magnitude of completeness of 1.3. This well‐recorded dataset provides a rare opportunity to study the relationship between the aftershocks and fault rupture of a major intraslab event. We use tomoDD algorithm to relocate 2038 M≥2 aftershocks with a regional 3D velocity model. The relocated aftershocks extend over a 20 km long zone between 47 and 57 km depth and are primarily confined to a high VP/VS region. Aftershocks form two clusters, a diffuse southern cluster and a steeply west‐dipping northern cluster with a gap in between where maximum slip has been inferred. We compute moment tensors for the Mw>4 aftershocks using a cut‐and‐paste method and careful selection of regional broadband stations. The moment tensor solutions do not exhibit significant variability or systematic differences between the northern and southern clusters and, on average, agree well with the mainshock fault‐plane parameters. We propose that the mainshock rupture initiated in the Yakutat lower crust or uppermost mantle and propagated both upward into the crust to near its top and downward into the mantle. The majority of the aftershocks are confined to the seismically active Yakutat crust and located both on and in the hanging wall of the mainshock fault rupture.

scholarly journals A SOURCE PARAMETERS STUDY OF THE AFTERSHOCK SEQUENCE OF THE KOZANI- GREVENA 1995 EARTHQUAKE BASED ON ACCELERATION RECORDS

2004 ◽  
Vol 36 (3) ◽  
pp. 1457 ◽  
Author(s):  
A. A. Panou ◽  
C. B. Papazachos ◽  
Ch. Papaioannou ◽  
P. M. Hatzidimitriou
Keyword(s):  
Source Parameters ◽  
Strong Motion ◽  
Aftershock Sequence ◽  
Propagation Path ◽  
Data Set ◽  
Near Surface ◽  
Anelastic Attenuation ◽  
Geological Formation ◽  
Good Agreement

Strong motion recordings of the May 13, 1995 Mw=6.6, earthquake sequence that occurred in the Kozani-Grevena region (Western Macedonia, Greece) have been analyzed for the determination of their source parameters. The data set for this study comes from a temporarily deployed accelerograph network and the source parameters using the shear-wave displacement spectra have been estimated. For this estimation the spectral records have been corrected for the site effects and for the propagation path (geometrical spreading and anelastic attenuation). The magnitude of each event was also re-calculated by estimating appropriate station corrections. The derived relationships arelogMo =(1.43 ±0.09) M, + (16.92 ± 0.29), 2.0 < ML< 5.0 (1)logfc = (-0.56± 0.08) · ML + (2.52 + 0.29), 2.0 < ML< 5.0 (2)logM0 = (-2.20 + 0.08) · log fc + (23.16 ± 0.84), 0.6 < fc < 10.0 (3)The near-surface attenuation parameter κ0 has also been determined for the strong motion stations sites. These values of κ0 are in good agreement with those of Margaris and Boore (1998) for the geological formation on which each station was positioned. The obtained source parameters are in good agreement with those from previous studies for the Aegean region.

scholarly journals ANALISIS PARAMETER SUMBER SPEKTRAL GEMPABUMI VTA (VULKANO TEKTONIK-A) TERHADAP AKTIVITAS VULKANIK GUNUNG SINABUNG

2019 ◽  
Vol 5 (1) ◽  
pp. 18-23
Author(s):  
Tri Kusmita ◽  
Kirbani Brotopuspito ◽  
Hetty Triastuty
Keyword(s):  
Stress Drop ◽  
Seismic Moment ◽  
Source Parameters ◽  
Radiation Energy ◽  
Angular Frequency ◽  
Moment Magnitude ◽  
Corner Frequency ◽  
Volcanic Earthquake ◽  
Seismic Volumes ◽  
The Relationship

The source parameters describe the different physical properties of seismic volumes under the volcanoes. Source parameters that can be used to distinguish seismic events that are generated by different types of volcanoes activities. Temporary changes of the spectral source parameters provided a description of the main events during the eruption process.  Source parameters are calculated by correlating the relationship between source frequency at spectral displacement (corner frequency) and source parameters based on spectral sources of the Brune model (1970). The angular frequency obtained by applying the FFT algorithm to the VTA spectral displacement. The source parameters analyzed from this VTA earthquake are the spectral slope, seismic moment, stress drop, length of rupture, moment magnitude and radiation energy. Based on the obtained corner frequency (12 Hz-13 Hz), seismic moment, moment magnitude and energy radiation respectively were at 0.2 -1.9 x 1012 Nm, 0.7 - 2 Mw, and 0.1 - 9.5 x 1015 erg. The length of rupture were from 144.2 to 243.1 m, the spectra slope has 2.1 - 7.8 dB/cm, and stress drop are 0.1 - 7,6 bar. From the results of this study, it can be concluded that the changes of spectra characteristic and fluctuate of source patrameters value of VTA earthquakes was asosiated with the different  volcanic activity of Sinabung. Keywords: spectral, VTA, source parameter, volcanic earthquake

Internal Cathodic Protection Of Large Steel Pipes Carrying Sea Water

CORROSION ◽  
1959 ◽  
Vol 15 (8) ◽  
pp. 35-40 ◽  
Author(s):  
JOHN H. MORGAN
Keyword(s):  
Cathodic Protection ◽  
Sea Water ◽  
Measuring Device ◽  
Steel Pipes ◽  
Large Steel ◽  
Diameter Pipe ◽  
The Moment ◽  
The Cost ◽  
The Relationship

Abstract The internal cathodic protection of large steel pipe carrying sea water is discussed both from the practical and the theoretical viewpoint. Systems considered involved use of such devices as concentric cylindrical anodes, off-center cylindrical anodes, wall mounted anodes, and central point lead alloy anodes fed with impressed current from a dc source. The cathodic protection was applied to both bare and coated pipe. Testing was done both in the laboratory and on a full scale level. The designing of a potential measuring device and the determination of protection criteria are considered briefly. Other topics discussed include coating the pipe interior, computing the costs of cathodic protection, and determining the relationship between anode separation and anode diameter in pipes with the same coating and electrolyte. It was found that coatings will effect the largest economies on the smaller diameter pipe where the cost of the cable is lowest and where smaller anode supports can be used with small anodes. At the moment the most economical method of protection seems to involve the use of a cheap readily applied coating of reasonable resistance and cathodic protection from point anodes mounted at or close to the center line of the pipe. 5.2.3

scholarly journals SOURCE PARAMETERS of STRONG EARTHQUAKES of the EARTH

2020 ◽  
pp. 244-249
Author(s):  
L. Chepkunas ◽  
L. Malyanova
Keyword(s):  
Seismic Moment ◽  
Source Parameters ◽  
P Wave ◽  
Apparent Stress ◽  
Dynamic Parameters ◽  
Strong Earthquakes ◽  
Rupture Length ◽  
The Earth ◽  
The World ◽  
The Moment

For nine strongest earthquakes in Russia and the World, dynamic parameters were determined. They were calculated from the P-wave spectra recorded by IRIS-IDA digital equipmentat Obninsk (OBN), Talaya (TLY) and Arti (ARU) stations at the epicentral distances =30–80°.The following parameters are given: seismic moment, rupture length, stress drop and apparent stress, average displacement during rupture of earthquake. The moment magnitude Mw obtained from seismic moment M0 at Obninsk, Talaya, and Arti stations was calculate by the formula of H. Kanamori.A comparison of the obtained parameters M0 and Mw with the data of the GCMT international center showed their proximity.

scholarly journals Spatio – Temporal Characteristics of the Aftershocks Sequences that followed the Strong Earthquakes in Ionian Islands, Greece

2020 ◽  
Author(s):  
Alexandra Moshou ◽  
George Drakatos ◽  
Vassilios Moussas ◽  
Panagiotis Argyrakis ◽  
Antonios Konstantaras ◽  
...  
Keyword(s):  
Moment Tensor ◽  
Source Parameters ◽  
Local Population ◽  
Secondary Data ◽  
Aftershock Sequence ◽  
Ionian Sea ◽  
Strong Earthquakes ◽  
Seismological Data ◽  
Spatio Temporal ◽  
The Moment

During the period January 2014 &ndash; October 2018, four strong earthquakes occurred in the Ionian Sea, Greece. A rich aftershock sequence followed each event of them. More analytically, according to the manual solutions of National Observatory of Athens, the first event (K1), occurred on 26 January 2014 in Kefallinia Island with magnitude ML = 5.8, which was followed by another in the same region (K2) on 3 February 2014 with magnitude ML = 5.7. The third event occurred on 17 November 2015, ML = 6.0 in Lefkas Island (L1) and the last on 25 October 2018, ML = 6.6 in Zande Island (Z1). The first three of these earthquakes caused moderate structural damages mainly in houses and produced particular unrest to the local population. This work presents first the calculation of the source parameters of the strong events as well as for all earthquakes with magnitude ML &gt; 4.0, using the methodology of the Moment tensor inversion and secondary data from permanent GPS stations were analyzed to confirm the findings from seismological data and to investigate the displacement due to the earthquakes.

Thromboplastin Related Differences in the Determination of International Normalised Ratio: A Cause for Concern?

1994 ◽  
Vol 72 (03) ◽  
pp. 426-429 ◽  
Author(s):  
S Kitchen ◽  
I D Walker ◽  
T A L Woods ◽  
F E Preston
Keyword(s):  
Patient Management ◽  
External Quality Assessment ◽  
Oral Anticoagulant Therapy ◽  
Warfarin Dosage ◽  
External Quality ◽  
External Quality Assessment Scheme ◽  
International Normalised Ratio ◽  
The Uk ◽  
The Relationship

SummaryWhen the International Normalised Ratio (INR) is used for control of oral anticoagulant therapy the same result should be obtained irrespective of the laboratory reagent used. However, in the UK National External Quality Assessment Scheme (NEQAS) for Blood Coagulation INRs determined using different reagents have been significantly different.For 18 NEQAS samples Manchester Reagent (MR) was associated with significantly lower INRs than those obtained using Diagen Activated (DA, p = 0.0004) or Instrumentation Laboratory PT-Fib HS (IL, p = 0.0001). Mean INRs for this group were 3.15, 3.61, and 3.65 for MR, DA, and IL respectively. For 61 fresh samples from warfarin-ised patients with INRs of greater than 3.0 the relationship between thromboplastins in respect of INR was similar to that observed for NEQAS data. Thus INRs obtained with MR were significantly lower than with DA or IL (p <0.0001). Mean INRs for this group were 4.01, 4.40, and 4.59 for MR, DA, and IL respectively.We conclude that the differences between INRs measured with the thromboplastins studied here are sufficiently great to influence patient management through warfarin dosage schedules, particularly in the upper therapeutic range of INR. There is clearly a need to address the issues responsible for the observed discrepancies.

COMPARATIVE ACTION OF VARIOUS OESTROGENIC COMPOUNDS ON MOUSE VAGINAL SIALIC ACIDS (II)

1969 ◽  
Vol 62 (4) ◽  
pp. 663-670 ◽  
Author(s):  
Lars Carlborg
Keyword(s):  
Sialic Acid ◽  
Response Curve ◽  
Sialic Acids ◽  
Clear Cut ◽  
Suitable Parameter ◽  
Sufficient Degree ◽  
Comparative Action ◽  
Relative Potencies ◽  
Good Agreement

ABSTRACT Oestrogens administered in lower doses than necessary to induce full cornification of the mouse vagina induce mucification. It was shown previously that the degree of mucification could be estimated by quantitative determination of sialic acids. A suitable parameter for oestrogen assay was the measurement of vaginal sialic acid concentration which exhibited a clear cut dose response curve. Eleven assays of various oestrogens were performed with this method. Their estimated relative potencies were in good agreement with other routine oestrogen assays. A statistically sufficient degree of precision was found. The sensitivity was of the same order, or slightly higher, than the Allen-Doisy test.

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