A 24-Yr-Long Seismic Bulletin for the European Arctic

2021 ◽  
Author(s):  
Johannes Schweitzer ◽  
Berit Paulsen ◽  
Galina N. Antonovskaya ◽  
Andrey V. Fedorov ◽  
Yana V. Konechnaya ◽  
...  
Keyword(s):  
Seismic Event ◽  
Seismic Events ◽  
Study Region ◽  
Entire Study ◽  
Svalbard Archipelago ◽  
Long Period ◽  
Northern Fennoscandia ◽  
European Arctic ◽  
International Seismological Centre ◽  
Different Sources

Abstract To understand the seismic activity in the European Arctic, the seismic bulletins for the region should be as complete as possible. We present the collection results of a new seismic event bulletin of the European Arctic (70° to 90° N, −15° to 75° E) for the 24-yr-long period 1990–2013. The contribution describes in detail the merging of the different sources taken in account for the compilation, the homogenization of the data, and the relocation of the seismic events. With respect to the International Seismological Centre bulletin, the new bulletin contains 5957 new seismic events and 58,242 new seismic onset readings from stations mostly located at regional distances. The gains are distributed over the entire study region, with the most significant contributions across the Svalbard archipelago, along the Knipovich and northern Mohns ridges, as well as northern Fennoscandia.

scholarly journals Impact of seasonal variations of ambient seismic noise level on the number of registered earthquakes in the Arctic regions

2019 ◽  
Vol 19 (3) ◽  
pp. 123-128
Author(s):  
ER Morozova ◽  
AP Turova
Keyword(s):  
Seasonal Variations ◽  
The Arctic ◽  
Svalbard Archipelago ◽  
Russian Academy Of Sciences ◽  
Arctic Regions ◽  
European Arctic ◽  
Academy Of Sciences ◽  
International Seismological Centre ◽  
The Impact

Researchers at the Seismological Laboratory of the Institute of Geodynamics and Geology of the Federal Center for Integrated Arctic Research of the Russian Academy of Sciences (FCIARctic) have been engaged in the seismological monitoring of the European Arctic sector since 2011. In this paper, we present a comparative assessment of the earthquakes spatial distribution in this region based on the data from the International Seismological Centre (ISC) and the FCIARctic’s Arkhangelsk Seismic Network (ASN) obtained in 2012–2016. The paper presents the waveforms of earthquakes occurred at the Gakkel Ridge and the Svalbard archipelago processed with the use of a Russian software package WSG (Windows Seismic Grafer) recommended by the Unified Geophysical Service of the Russian Academy of Sciences. A standard 4–8 Hz bandpass filter was used for the processing of regional Arctic earthquakes. The impact of seasonal variations on the quality of earthquakes registration was analysed based on the seismograms recorded by the ASN’s island-based Arctic stations from 2012 to 2014 The same analysis was done for the central broadband sensor SPA0 of the Norwegian NORSAR-owned SPITS group installed at the Svalbard archipelago. A correlation has been established between the number of earthquakes recorded by the ASN’s island Arctic stations and SPA0 station. The number of regional earthquakes, recorded by ASN’s island Arctic stations is is smaller in summer-autumn periods than in winter periods. Forthe SPA0 station, which is part of SPITS group, there is not seasonality in the number of registered earthquakes. Generally, earthquakes are recorded uniformly, exception on January. This might be due to the increased seismic activity in the Svalbard archipelago during that period.

Geochemical evidence of different sources of long-period seismic events at Deception volcano, South Shetland Islands, Antarctica

2015 ◽  
Vol 27 (6) ◽  
pp. 557-565 ◽  
Author(s):  
Eleazar Padrón ◽  
Pedro A. Hernández ◽  
Enrique Carmona ◽  
Nemesio M. Pérez ◽  
Gladys Melián ◽  
...  
Keyword(s):  
Time Series ◽  
Detailed Analysis ◽  
Pressure Fluctuations ◽  
Temporal Correlation ◽  
Hydrothermal Systems ◽  
South Shetland Islands ◽  
Seismic Events ◽  
Shetland Islands ◽  
Long Period ◽  
Different Sources

AbstractThis is the first detailed analysis of a CO2 diffuse degassing time series from Deception volcano, South Shetland Islands, Antarctica, performed during an episode of anomalously high long-period (LP) seismicity. Diffuse CO2 emissions measured by an automatic geochemical station between 7 December 2009 and 13 February 2010 showed an excellent temporal agreement with the LP seismicity in December 2009. The absence of such a temporal correlation with the second burst of seismicity that occurred in late January 2010 suggests a different source for this LP activity. This was confirmed by analysis of seismic array data. The LP seismicity observed during December 2009 was caused by fluid-driven cracks that originated from pressure fluctuations in the volcano-hydrothermal systems beneath Deception volcano that were probably caused by a deep injection of undegassed magma before December 2009. The diffuse CO2 degassing data have provided evidence of the activation of at least two different sources of seismicity during the study period at Deception volcano.

Performance of a rotational sensor at Etna, Italy focusing on back-azimuth estimations of volcano-seismic events

2021 ◽  
Author(s):  
Martina Rosskopf ◽  
Eva P. S. Eibl ◽  
Gilda Currenti ◽  
Philippe Jousset ◽  
Joachim Wassermann ◽  
...  
Keyword(s):  
Rotation Rate ◽  
Mount Etna ◽  
Seismic Events ◽  
Volcano Seismology ◽  
Rotational Seismology ◽  
Long Period ◽  
Tectonic Events ◽  
Back Azimuth ◽  
Seismic Wavefield

<p>The field of rotational seismology has only recently emerged. Portable 3 component rotational sensors are commercially available since a few years which opens the pathway for a first use in volcano-seismology. The combination of rotational and translational components of the wavefield allows identifying and filtering for specific seismic wave types, estimating the back azimuth of an earthquake, and calculating local seismic phase velocities.</p><p>Our work focuses on back-azimuth calculations of volcano-tectonic and long-period events detected at Etna volcano in Italy. Therefore, a continuous full seismic wavefield of 30 days was recorded by a BlueSeis-3A, the first portable rotational sensor, and a broadband Trillium Compact seismometer located next to each other at Mount Etna in August and September of 2019. In this study, we applied two methods for back-azimuth calculations. The first one is based on the similarity of the vertical rotation rate to the horizontal acceleration and the second one uses a polarization analysis from the two horizontal components of the rotation rate. The estimated back-azimuths for volcano-tectonic events were compared to theoretical back-azimuths based on the INGV event catalog and the long-period event back-azimuths were analyzed for their dominant directions. We discuss the quality of our back azimuths with respect to event locations and evaluate the sensitivity and benefits of the rotational sensor focusing on volcano-seismic events on Etna regarding the signal to noise ratios, locations, distances, and magnitudes.</p>

scholarly journals Long-term accumulation and improvements in seismic event data for the polar regions by the International Seismological Centre

Polar Science ◽  
2015 ◽  
Vol 9 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Dmitry A. Storchak ◽  
Masaki Kanao ◽  
Emily Delahaye ◽  
James Harris
Keyword(s):  
Seismic Event ◽  
Polar Regions ◽  
Event Data ◽  
International Seismological Centre

Short visits reveal consistent patterns of interyear and intercolony variation in seabird nestling diet and performance

2002 ◽  
Vol 80 (12) ◽  
pp. 2190-2199 ◽  
Author(s):  
D F Bertram ◽  
T Golumbia ◽  
G K Davoren ◽  
A Harfenist ◽  
J Brown
Keyword(s):  
Growth Performance ◽  
Large Scale ◽  
Southern Oscillation ◽  
Large Contribution ◽  
Fish Prey ◽  
Study Region ◽  
Entire Study ◽  
Nestling Growth ◽  
Nestling Development ◽  
Nestling Diet

To investigate the utility of short visits to seabird colonies to gauge nestling growth performance and diet, in 4 consecutive years (1995–1998) we measured nestling development and diet of Rhinoceros Auklets (Cerorhinca monocerata) at three colonies in British Columbia: Seabird Rocks, Triangle Island, and SGaang Gwaii (Anthony Island). In all years, nestlings of a given wing length on Triangle Island were significantly smaller than those on Seabird Rocks or SGaang Gwaii. Meals were also significantly lighter on Triangle Island than on Seabird Rocks or SGaang Gwaii; meals on the latter two islands were indistinguishable in mass. Retarded nestling development and small meal size on Triangle Island likely reflect the large contribution of rockfish (Sebastes spp.) to nestling diet on that colony alone. The intercolony differences in nestling performance appear to reflect the strong influence of local fish prey populations. Nonetheless, a united decline in performance in 1996 and subsequent increase on all colonies suggest the influence of large-scale ocean climate phenomena on our entire study region and beyond. We did not, however, observe noticeable effects of the 1997–1998 El Niño Southern Oscillation event on nestling growth performance or diet. We discuss the utility of our short-visit techniques for seabird-monitoring programs.

The Koyna earthquake of December 10 1967: A multiple seismic event

1971 ◽  
Vol 61 (1) ◽  
pp. 167-176 ◽  
Author(s):  
Harsh K. Gupta ◽  
B. K. Rastogi ◽  
Hari Narain
Keyword(s):  
Seismic Event ◽  
Strong Motion ◽  
Seismic Events ◽  
Field Observations ◽  
Rupture Velocity ◽  
P Waves ◽  
Seismic Arrays ◽  
Sine Curve ◽  
Curve Method ◽  
Different Origin

abstract The analysis of P waves recorded at seismological observatories and seismic arrays at teleseismic distances and strong motion seismographs located at Koyna Dam suggest the Koyna earthquake of December 10 1967 to be a complex multiple event. Six of the events could be identified, and the second and third events are located with respect to the initiation using the Gutenberg sine-curve method at distances of 6 and 17 km due south, the average rupture velocity being 3.4 km/sec. The findings are consistent with the field observations and the different origin times, epicenters and magnitudes reported for the earthquake. Seismic array records are found to be very useful in examining the multiplicity of seismic events.

scholarly journals Spatial Paradigms in Road Networks and Their Delimitation of Urban Boundaries Based on KDE

2020 ◽  
Vol 9 (4) ◽  
pp. 204 ◽  
Author(s):  
Yuying Lin ◽  
Xisheng Hu ◽  
Mingshui Lin ◽  
Rongzu Qiu ◽  
Jinguo Lin ◽  
...  
Keyword(s):  
Spatial Data ◽  
Rural Areas ◽  
Urban Areas ◽  
Critical Role ◽  
Road Networks ◽  
Spatial Data Analysis ◽  
Easy Method ◽  
Study Region ◽  
Entire Study ◽  
Depth Analysis

An in-depth analysis of urban road network distribution plays a critical role in understanding the urbanization process. However, effective ways to quantitatively analyze the spatial paradigms of road networks are still lacking, and few studies have utilized road networks to rapidly identify urban areas of a region. Thus, using a fast-developing region in the south-eastern costal region of China, Fuzhou City, as a case, we introduced kernel density estimation (KDE) to characterize road networks and quantified the area’s spatial heterogeneity using exploratory spatial data analysis (ESDA) and semivariance analysis (SA). The results show that there is an uneven spatial distribution of the networks both at the regional and downtown levels. At the regional level, there is a conspicuous polarization in the road distribution, with the KDE being much higher in the urban areas than in the rural areas; at the downtown level, the KDE gradually decreases from the center to the periphery. Quantitatively, the ranges of the spatial dependence of the networks are approximately 25 km for the entire study region and 12 km for the downtown area. Additionally, the spatial variations vary among different directions, with greater variations in the northeast–southwest and the southeast–northwest directions compared with the other directions, which is in line with the urban sprawl policy of the study area. Both the qualitative and quantitative results show that the distribution of road networks has a clear urban–rural dual structure, which indicates that road networks can be an active tool in identifying the urban areas of a region. To this end, we propose a quick and easy method to delimit urban areas using KDE. The extraction results of KDE are better than those of the index-based built-up index (IBI), indicating the effectivity and feasibility of our proposed method to identify the urban areas in the region. This research sheds new light on urbanization development research.

Early Cambrian Seismic Events and Their Tectonic Significance in Western Zhejiang

2012 ◽  
Vol 524-527 ◽  
pp. 42-48
Author(s):  
Fu Sheng Guo ◽  
Zhao Bin Yan ◽  
Liu Qin Chen
Keyword(s):  
Seismic Event ◽  
Regional Distribution ◽  
Sedimentary Rocks ◽  
Seismic Events ◽  
Time Interval ◽  
Early Cambrian ◽  
Distribution Characteristics ◽  
Early Paleozoic ◽  
Tectonic Events ◽  
Tectonic Significance

The two early Cambrian seismic events could be found from sedimentary rocks at Peilingjiao section of Kaihua County, Baishi and Fangcun sections of Changshan County in western Zhejiang, except for Jiangshan area. The seismic event at Baishi outcrop can be correlated to the second seismic event at Peilingjiao section. Taking Fangcun as epicenter of the second seismic event, the magnitude of paleoseism in western Zhejiang is about 7~7.6. According to investigation on regional distribution of seismic events, the two seismic activities should be regulated by large Kaihua-Chun’an fault, but unrelated with Jiangshan-Shaoxing fault or Changshan-Xiaoshan fault. However, the formation time of Kaihua-Chun’an fault has not yet been determinate. Based on controlling on Silurian, the possible formation age was inferred to early Paleozoic. The distribution characteristics of seismites indicate that the Kaihua-Chun’an fault was already being active during early Cambrian and seismic activities may be response to Sinian tectonic events in western Zhejiang. By the way of analysis on paleoseismic rhythm, the time interval of the two seismic events in western Zhejiang is less than 5.0 Ma, which may be the result of early frequent activities of Kaihua-Chun’an fault.

LONG‐PERIOD SIGNAL PROCESSING RESULTS FOR THE LARGE APERTURE SEISMIC ARRAY

Geophysics ◽  
1969 ◽  
Vol 34 (3) ◽  
pp. 305-329 ◽  
Author(s):  
J. Capon ◽  
R. J. Greenfield ◽  
R. T. Lacoss
Keyword(s):  
Signal Processing ◽  
Surface Wave ◽  
Maximum Likelihood ◽  
Surface Waves ◽  
Body Wave ◽  
Seismic Array ◽  
Seismic Events ◽  
Long Period ◽  
Large Aperture ◽  
Period Data

The results of a series of off‐line signal processing experiments are presented for long‐period data obtained from the Large Aperture Seismic Array (LASA) located in eastern Montana. The signal‐to‐noise ratio gains obtained with maximum‐likelihood processing, as well as other simpler forms of processing, are presented for body‐wave as well as surface‐wave phases. A discussion of the frequency‐wavenumber characteristics of the noise which led to these results is also given. On the basis of these experiments, several recommendations are made concerning optimum long‐period array configurations and on‐line or off‐line processing methods. The usefulness of maximum‐likelihood processing in suppressing an interfering teleseism is demonstrated. An experiment is given in which maximum‐likelihood processing achieved about 20 db suppression of an interfering teleseism, while simpler forms of processing such as beam‐forming obtained about 11 db. The matched filtering of surface waves using chirp waveforms is shown to be highly effective. A useful discriminant for distinguishing between natural seismic events and underground nuclear explosions, using both the long‐period and short‐period data, was found to be the relationship between the surface‐wave and body‐wave magnitudes. Measurements of this discriminant made on events from four tectonic regions of the earth are presented. It is shown that 60 and 100 percent detectability of surface waves for natural seismic events from the Central Asian‐Kurile Islands‐Kamchatka region occurs at about LASA body‐wave magnitudes 4.5 and 4.9, respectively.

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