scholarly journals Supplemental Material: Seismicity trends and detachment fault structure at 13°N, Mid-Atlantic Ridge

2020 ◽  
Author(s):  
Ross Parnell-Turner ◽  
et al.
Keyword(s):  
Detachment Fault ◽  
Data Repository ◽  
Earthquake Catalog ◽  
Data Set ◽  
Fault Structure ◽  
Additional Information ◽  
Mid Atlantic Ridge ◽  
Earthquake Data

Additional information and figures describing the acquisition and processing of the micro-earthquake data set, including links to data repository and 3-D visualization of the earthquake catalog.<br>

scholarly journals Supplemental Material: Seismicity trends and detachment fault structure at 13°N, Mid-Atlantic Ridge

2020 ◽  
Author(s):  
Ross Parnell-Turner ◽  
et al.
Keyword(s):  
Detachment Fault ◽  
Data Repository ◽  
Earthquake Catalog ◽  
Data Set ◽  
Fault Structure ◽  
Additional Information ◽  
Mid Atlantic Ridge ◽  
Earthquake Data

Additional information and figures describing the acquisition and processing of the micro-earthquake data set, including links to data repository and 3-D visualization of the earthquake catalog.<br>

Application of RTM 3D angle gathers to wide-azimuth data subsalt imaging

Geophysics ◽  
2011 ◽  
Vol 76 (5) ◽  
pp. WB175-WB182 ◽  
Author(s):  
Yan Huang ◽  
Bing Bai ◽  
Haiyong Quan ◽  
Tony Huang ◽  
Sheng Xu ◽  
...  
Keyword(s):  
Model Updating ◽  
Velocity Model ◽  
Azimuth Angle ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Data Set ◽  
Additional Information ◽  
Time Migration ◽  
Reflection Angle ◽  
Subsalt Imaging

The availability of wide-azimuth data and the use of reverse time migration (RTM) have dramatically increased the capabilities of imaging complex subsalt geology. With these improvements, the current obstacle for creating accurate subsalt images now lies in the velocity model. One of the challenges is to generate common image gathers that take full advantage of the additional information provided by wide-azimuth data and the additional accuracy provided by RTM for velocity model updating. A solution is to generate 3D angle domain common image gathers from RTM, which are indexed by subsurface reflection angle and subsurface azimuth angle. We apply these 3D angle gathers to subsalt tomography with the result that there were improvements in velocity updating with a wide-azimuth data set in the Gulf of Mexico.

Southern California Earthquake Data Now Available in the AWS Cloud

2021 ◽  
Author(s):  
Ellen Yu ◽  
Aparna Bhaskaran ◽  
Shang-Lin Chen ◽  
Zachary E. Ross ◽  
Egill Hauksson ◽  
...  
Keyword(s):  
Southern California ◽  
Data Availability ◽  
First Year ◽  
Earthquake Catalog ◽  
High Data ◽  
Seismic Waveform ◽  
Challenges And Opportunities ◽  
Amazon Web Services ◽  
Computationally Intensive ◽  
Earthquake Data

Abstract The Southern California Earthquake Data Center is hosting its earthquake catalog and seismic waveform archive in the Amazon Web Services (AWS) Open Dataset Program (s3://scedc-pds; us-west-2 region). The cloud dataset’s high data availability and scalability facilitate research that uses large volumes of data and computationally intensive processing. We describe the data archive and our rationale for the formats and data organization. We provide two simple examples to show how storing the data in AWS Simple Storage Service can benefit the analysis of large datasets. We share usage statistics of our data during the first year in the AWS Open Dataset Program. We also discuss the challenges and opportunities of a cloud-hosted archive.

scholarly journals Comparison between XBT data and TOPEX/Poseidon satellite altimetry in the Ligurian-Tyrrhenian area

2003 ◽  
Vol 21 (1) ◽  
pp. 123-135 ◽  
Author(s):  
S. Vignudelli ◽  
P. Cipollini ◽  
F. Reseghetti ◽  
G. Fusco ◽  
G. P. Gasparini ◽  
...  
Keyword(s):  
Pilot Project ◽  
Atlantic Water ◽  
Data Sets ◽  
Tyrrhenian Sea ◽  
Satellite Altimeter ◽  
Ligurian Sea ◽  
Data Set ◽  
Additional Information ◽  
Forecasting System ◽  
Computational Errors

Abstract. From September 1999 to December 2000, eXpendable Bathy-Thermograph (XBT) profiles were collected along the Genova-Palermo shipping route in the framework of the Mediterranean Forecasting System Pilot Project (MFSPP). The route is virtually coincident with track 0044 of the TOPEX/Poseidon satellite altimeter, crossing the Ligurian and Tyrrhenian basins in an approximate N–S direction. This allows a direct comparison between XBT and altimetry, whose findings are presented in this paper. XBT sections reveal the presence of the major features of the regional circulation, namely the eastern boundary of the Ligurian gyre, the Bonifacio gyre and the Modified Atlantic Water inflow along the Sicily coast. Twenty-two comparisons of steric heights derived from the XBT data set with concurrent realizations of single-pass altimetric heights are made. The overall correlation is around 0.55 with an RMS difference of less than 3 cm. In the Tyrrhenian Sea the spectra are remarkably similar in shape, but in general the altimetric heights contain more energy. This difference is explained in terms of oceanographic signals, which are captured with a different intensity by the satellite altimeter and XBTs, as well as computational errors. On scales larger than 100 km, the data sets are also significantly coherent, with increasing coherence values at longer wavelengths. The XBTs were dropped every 18–20 km along the track: as a consequence, the spacing scale was unable to resolve adequately the internal radius of deformation (< 20 km). Furthermore, few XBT drops were carried out in the Ligurian Sea, due to the limited north-south extent of this basin, so the comparison is problematic there. On the contrary, the major features observed in the XBT data in the Tyrrhenian Sea are also detected by TOPEX/Poseidon. The manuscript is completed by a discussion on how to integrate the two data sets, in order to extract additional information. In particular, the results emphasize their complementariety in providing a dynamically complete description of the observed structures. Key words. Oceanography: general (descriptive and regional oceanography) Oceanography: physical (sea level variations; instruments and techniques)

Nodal Seismograph Recordings of the 2019 Ridgecrest Earthquake Sequence

2020 ◽  
Vol 91 (6) ◽  
pp. 3622-3633
Author(s):  
Rufus D. Catchings ◽  
Mark R. Goldman ◽  
Jamison H. Steidl ◽  
Joanne H. Chan ◽  
Amir A. Allam ◽  
...  
Keyword(s):  
Wave Velocity ◽  
Large Volume ◽  
Ambient Noise ◽  
Temporal Variations ◽  
Earthquake Sequence ◽  
S Wave ◽  
Data Set ◽  
Fault Structure ◽  
Nodal Data ◽  
Dense Arrays

Abstract The 2019 Ridgecrest, California, earthquake sequence included Mw 6.4 and 7.1 earthquakes that occurred on successive days beginning on 4 July 2019. These two largest earthquakes of the sequence occurred on orthogonal faults that ruptured the Earth’s surface. To better evaluate the 3D subsurface fault structure, (P- and S-wave) velocity, 3D and temporal variations in seismicity, and other important aspects of the earthquake sequence, we recorded aftershocks and ambient noise using up to 461 three-component nodal seismographs for about two months, beginning about one day after the Mw 7.1 mainshock. The ∼30,000Mw≥1 earthquakes that were recorded on the dense arrays provide an unusually large volume of data with which to evaluate the earthquake sequence. This report describes the recording arrays and is intended to provide metadata for researchers interested in evaluating various aspects of the 2019 Ridgecrest earthquake sequence using the nodal data set.

scholarly journals Investigating the earthquake catalog of the National Observatory of Athens

2009 ◽  
Vol 9 (3) ◽  
pp. 905-912 ◽  
Author(s):  
G. Chouliaras
Keyword(s):  
B Value ◽  
Spatial And Temporal Variability ◽  
Earthquake Catalog ◽  
National Observatory ◽  
Data Set ◽  
Seismicity Rate ◽  
Earthquake Prediction Research ◽  
The Times ◽  
Seismicity Rate Changes ◽  
Selection Of

Abstract. The earthquake catalog of the National Observatory of Athens (NOA) since the beginning of the Greek National Seismological Network development in 1964, is compiled and analyzed in this study. The b-value and the spatial and temporal variability of the magnitude of completeness of the catalog is determined together with the times of significant seismicity rate changes. It is well known that man made inhomogeneities and artifacts exist in earthquake catalogs that are produced by changing seismological networks and in this study the chronological order of periods of network expansion, instrumental upgrades and practice and procedures changes at NOA are reported. The earthquake catalog of NOA is the most detailed data set available for the Greek area and the results of this study may be employed for the selection of trustworthy parts of the data in earthquake prediction research.

scholarly journals Normative Data for Derived Measures and Discrepancy Scores for the Uniform Data Set 3.0 Neuropsychological Battery

2019 ◽  
Vol 35 (1) ◽  
pp. 75-89 ◽  
Author(s):  
Paulina V Devora ◽  
Samantha Beevers ◽  
Andrew M Kiselica ◽  
Jared F Benge
Keyword(s):  
Normative Data ◽  
Lewy Bodies ◽  
Data Repository ◽  
Neuropsychological Battery ◽  
Cross Sectional ◽  
Data Set ◽  
Validity Data ◽  
Retention Score ◽  
Discrepancy Scores ◽  
Error Index

Abstract Objective The Uniform Data Set 3.0 (UDS 3.0) neuropsychological battery is a recently published battery intended for clinical research with older adult populations. While normative data for the core measures has been published, several additional discrepancy and derived scores can also be calculated. We present normative data for Trail Making Test (TMT) A & B discrepancy and ratio scores, semantic and phonemic fluency discrepancy scores, Craft Story percent retention score, Benson Figure percent retention score, difference between verbal and visual percent retention, and an error index. Method Cross-Sectional data from 1803 English speaking, cognitively normal control participants were obtained from the NACC central data repository. Results Descriptive information for derived indices is presented. Demographic variables, most commonly age, demonstrated small but significant associations with the measures. Regression values were used to create a normative calculator, made available in a downloadable supplement. Statistically abnormal values (i.e., raw scores corresponding to the 5th, 10th, 90th, and 95th percentiles) were calculated to assist in practical application of normative findings to individual cases. Preliminary validity of the indices are demonstrated by a case study and group comparisons between a sample of individuals with Alzheimer's (N = 81) and Dementia with Lewy Bodies (DLB; N = 100). Conclusions Clinically useful normative data of such derived indices from the UDS 3.0 neuropsychological battery are presented to help researchers and clinicians interpret these scores, accounting for demographic factors. Preliminary validity data is presented as well along with limitations and future directions.

Phylogeography of black bears (Ursus americanus) of the Pacific Northwest

2000 ◽  
Vol 78 (7) ◽  
pp. 1218-1223 ◽  
Author(s):  
Karen D Stone ◽  
Joseph A Cook
Keyword(s):  
Pacific Northwest ◽  
Pacific Coast ◽  
Ursus Americanus ◽  
Black Bear ◽  
Data Set ◽  
Southeast Alaska ◽  
Additional Information ◽  
The North ◽  
The Pacific ◽  
And Control

Phylogeographic study across codistributed taxa provides temporal and spatial perspectives on the assemblage of communities. A repeated pattern of intraspecific diversification within several taxa of the Pacific Northwest has been documented, and we contribute additional information to this growing data set. We analyzed variation in two mitochondrial genes (cytochrome b and control region) for the black bear (Ursus americanus) and expand previous analyses of phylogeographic variation. Two lineages (coastal and continental) exist; the coastal lineage extends along the Pacific coast from the Takhin River north of Glacier Bay National Park, southeast Alaska, to northern California, whereas the continental lineage is more widespread, occurring from central Alaska to the east coast. Both lineages occur along the coast of southeast Alaska, where interlineage divergence ranged from 3.1 to 3.6% (uncorrected p distances). Multiple lineages of other species have also been identified from southeast Alaska, indicating a complex history for the assembly of biotic communities along the North Pacific coast. The overlapping of the distributions of the black bear lineages with those of other birds and mammals suggests comparable routes of colonization.

scholarly journals Seismicity of the Atlantis Massif detachment fault, 30°N at the Mid-Atlantic Ridge

2012 ◽  
Vol 13 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
John A. Collins ◽  
Deborah K. Smith ◽  
Jeffrey J. McGuire
Keyword(s):  
Detachment Fault ◽  
Atlantis Massif ◽  
Mid Atlantic Ridge
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