scholarly journals SEISMICITY of NORTHERN EURASIA in 2015

2021 ◽  
pp. 10-30
Author(s):  
A. Malovichko ◽  
N. Petrova ◽  
I. Gabsatarova ◽  
R. Mikhailova ◽  
V. Levina ◽  
...  
Keyword(s):  
Seismic Station ◽  
Seismic Energy ◽  
Annual Number ◽  
Northern Eurasia ◽  
Middle Urals ◽  
Induced Earthquakes ◽  
Seismic Regime ◽  
East European ◽  
Tectonic Earthquakes ◽  
Seismic Networks

The review of the Northern Eurasia seismicity for 2015 includes a description of seismic networks, the results of analysis of the seismic regime and individual noticeable earthquakes in 16 regions of Russia and neighbouring countries. Seismic monitoring was carried out by the networks of seismic station of Russia, Azerbaijan, Armenia, Belarus, Kazakhstan, Kyrgyzstan, Latvia, Moldova, Turkmenistan, Tajikistan, Uzbekistan, Ukraine, including 599 digital, 7 analogue stations and eight seismic groups. In 2015, these networks registered about 27 thousand tectonic earthquakes, over 6 thousand volcanic earthquakes, 599 explosions, 23 mountain-tectonic shocks and induced earthquakes. Focal mechanisms of 592 earthquakes were determined, the information on manifestations of 449 perceptible earthquakes was collected. 26 shocks were felt in settlements of Northern Eurasia with an intensity Ii≥5. According to estimates of the annual number and released seismic energy in 2015 in comparison with the long-term characteristics of the seismic regime, the seismic process in most regions of Northern Eurasia proceeded in the “background” regime. An exception is Tajikistan and adjacent territories, where two strong earthquakes occurred – the Hindu Kush earthquake on October 26 with Mw=7.5, h=230 km in northern Afghanistan, near the border with Tajikistan, and the Sarez earthquake on December 7 with Mw=7.2, Ms=7.6, h=20 km in Tajikistan. Both earthquakes were accompanied by numerous aftershocks and were felt in Tajikistan with intensities Imax=7 and Imax=7–8 respectively, on the MSK-64 scale. Notable event on the territory of Northern Eurasia in 2015 is the emergence of the Muyakan sequence of earthquakes, the largest for the period of instrumental observations in the region "Baikal and Transbaikalia", as a result of which the number of recorded earthquakes in the region quadrupled concerning 2014. The other interesting fact is occurrence of tangible earthquakes in the regions, traditionally considered weakly seismic – near the Semipalatinsk test area in Eastern Kazakhstan (Chingiz earthquake on January 20, Ms=4.1, I0=5–6), in the Middle Urals (Middle Ural earthquake on October 18 with ML=4.7, I0=6) and in the southwest of East -European platform (Poltava earthquake on February 3 with KR=10.7, I0=6).

scholarly journals SEISMICITY OF NORTHERN EURASIA in 2014

2020 ◽  
pp. 10-26
Author(s):  
Alexey Malovichko ◽  
Nataliya Petrova ◽  
Irina Gabsatarova ◽  
Oleg Starovoit ◽  
E. Rogozhin ◽  
...  
Keyword(s):  
Seismic Energy ◽  
Focal Mechanisms ◽  
Northern Eurasia ◽  
Seismic Process ◽  
Fold Belt ◽  
Seismic Regime ◽  
The Past ◽  
Source Zones ◽  
Regions Of Russia

An overview of Northern Eurasia seismicity in 2014 is given. This territory includes 16 regions of Russia and neighboring countries. Seismic monitoring was carried out by 618 stationary seismic stations, including 591 digital, 27 analog stations and eight seismic groups. Also, temporary stations operated in some re-gions. These networks have registered over 30 thousand tectonic and volcanic earthquakes, for 571 of them the focal mechanisms are determined. According to the data collected and presented in the Annual, 413 earthquakes were felt in settlements of Northern Eurasia in 2014, manifestations of 14 of them were surveyed and described in the special articles of this issue, together with data on the focal mechanisms, preceding seismicity, aftershock processes and seismotectonic conditions. Estimates of the number of earthquakes and seismic energy released in 2014 in the regions of Northern Eurasia in comparison with long-term characteristics of seismic regime indicate that in most regions the seismic process proceeded in the “background” or “background lowered” regimes accor-ding to the definition on the SOUS'09 scale. Only the level of seismicity in the Pribaikalye and Transbaikalia region is assessed as “background increased”. The intensification of seismicity in the source zones of the past strongest earthquakes in the Alpine-Himalayan collision-fold belt – Crimean 1927, Spitak 1988, Zakatala 2012 – is noted. The tangible earthquakes that occurred in the previously aseismic areas of the Siberian and Turan platforms – Gonam earthquake on January 4 with KP=14.2, I0=8, Boguchan earthquake on January 17 with KP=13.3, I0=7 and Karaganda earthquake on June 21 with KP=11.7, I0=5–6 – indicate the need to revise the concept of a low seismic hazard in these platform areas.

scholarly journals URAL

2019 ◽  
pp. 256-267 ◽  
Author(s):  
Aleksey Malovichko ◽  
Ruslan Dyagilev ◽  
F. Verkholantsev ◽  
I. Golubeva ◽  
T. Zlobina
Keyword(s):  
Seismic Activity ◽  
Wide Spectrum ◽  
Seismic Network ◽  
Seismic Events ◽  
Induced Earthquakes ◽  
Rock Falls ◽  
Seismic Regime ◽  
Seismic Stations ◽  
Chelyabinsk Meteorite ◽  
Tectonic Earthquakes

The article shows the monitoring results of the Ural region seismic network in 2013. It describes the seismic stations and registration abilities of the network. The analysis of seismic activity in Ural in 2013 and infor-mation about changes of the regional seismic regime since 2006 are given. The seismicity in the Ural is unique as it is presented by a wide spectrum of natural earthquakes (tectonic, earthquakes due to collapse, impact) as well as induced earthquakes (explosions, rock falls, rockbursts). Whereby the number of explosions in the region predominates among other seismic events, the number of rockbursts is much more than tectonic earth-quakes. A structural ordering can be seen for tectonic earthquakes. They tend to the basic geologic structure of the region to the Main Ural Fault. The induced events tend to mining regions. Also, there is a weak scat-tered seismicity that is typical for platform territories. Acting since 1999 the regional seismic network pro-vides the representative registration on the magnitude level ML≥2.5. In general in 2013 in Ural it was regis-tered 173 seismic events, and their basic seismic parameters were determined. The common number of in-dustrial explosions was 173. The summarized seismic explosions energy was 3.99E+9 Joules. The number of rockbursts was 29; their seismic energy was 2.82E+9 Joules. The five tectonic earthquakes made the min-imal contribution to the seismicity of the region. The unique event registered by seismic network was the ex-plosion of Chelyabinsk meteorite, and its parameters are shown in the article. Parameters of all mentioned above seismic events are presented in catalogue. The strongest events with ML≥3.0 including Chelyabinsk meteorite explosion, are considered separately, including their seismograms and parameters provided by other international seismic centers. The article shows the map with the actual locations of regional seismic stations and event epicenters in 2013. Generally the seismic regime of the region in 2013 was quite calm; the summarized seismic explosions energy was low. The trend to the seismic activity decay continues since 2010. The location of the natural and induced seismic events in space confirms the active zones previously determined.

scholarly journals Indicators for site characterization at seismic station: recommendation from a dedicated survey

2021 ◽  
Author(s):  
Giovanna Cultrera ◽  
Cécile Cornou ◽  
Giuseppe Di Giulio ◽  
Pierre-Yves Bard
Keyword(s):  
Seismic Station ◽  
International Workshop ◽  
Site Characterization ◽  
Companion Paper ◽  
Background Information ◽  
Online Questionnaire ◽  
Seismic Records ◽  
Seismic Networks ◽  
High Level ◽  
Data Acquisition And Processing

AbstractIn recent years, the permanent seismic networks worldwide have largely increased, raising the amount of earthquake signals and the applications using seismic records. Although characterization of the soil properties at recording stations has a large impact on hazard estimates, it has not been implemented so far in a standardized way for reaching high-level metadata. To address this issue, we built an online questionnaire for the identification of the indicators useful for a reliable site characterization at a seismic station. We analysed the answers of a large number of experts in different fields, which allowed us to rank 24 different indicators and to identify the most relevant ones: fundamental frequency (f0), shear-wave velocity profile (VS), time-averaged Vs over 30 m (VS30), depth of seismological and engineering bedrock (Hseis_bed and Heng_bed), surface geology and soil class. Moreover, the questionnaire proposed two additional indices in terms of cost and difficulty to obtain a reliable value of each indicator, showing that the selection of the most relevant indicators results from a complex balance between physical relevancy, average cost and reliability. For each indicator we propose a summary report, provided as editable pdf, containing the background information of data acquisition and processing details, with the aim to homogenize site metadata information at European level and to define the quality of the site characterization (see companion paper Di Giulio et al. 2021). The selected indicators and the summary reports have been shared within European and worldwide scientific community and discussed in a dedicated international workshop. They represent a first attempt to reach a homogeneous set of high-level metadata for site characterization.

Monazite stability, composition and geochronology as tracers of Paleoproterozoic events at the eastern margin of the East European Craton (Taratash complex, Middle Urals)

Lithos ◽  
2012 ◽  
Vol 132-133 ◽  
pp. 82-97 ◽  
Author(s):  
Sven Sindern ◽  
Axel Gerdes ◽  
Yuri L. Ronkin ◽  
Annika Dziggel ◽  
Ralf Hetzel ◽  
...  
Keyword(s):  
East European Craton ◽  
Middle Urals ◽  
East European ◽  
Eastern Margin

Risk from Oklahoma’s Induced Earthquakes: The Cost of Declustering

2020 ◽  
Author(s):  
Jeremy Maurer ◽  
Deborah Kane ◽  
Marleen Nyst ◽  
Jessica Velasquez
Keyword(s):  
Financial Risk ◽  
B Value ◽  
Earthquake Risk ◽  
Eastern United States ◽  
Induced Earthquakes ◽  
Magnitude Distribution ◽  
Seismicity Rate ◽  
Seismicity Rates ◽  
Tectonic Earthquakes ◽  
Frequency Magnitude

ABSTRACT The U.S. Geological Survey (USGS) has for each year 2016–2018 released a one-year seismic hazard map for the central and eastern United States (CEUS) to address the problem of induced and triggered seismicity (ITS) in the region. ITS in areas with historically low rates of earthquakes provides both challenges and opportunities to learn about crustal conditions, but few scientific studies have considered the financial risk implications of damage caused by ITS. We directly address this issue by modeling earthquake risk in the CEUS using the 1 yr hazard model from the USGS and the RiskLink software package developed by Risk Management Solutions, Inc. We explore the sensitivity of risk to declustering and b-value, and consider whether declustering methods developed for tectonic earthquakes are suitable for ITS. In particular, the Gardner and Knopoff (1974) declustering algorithm has been used in every USGS hazard forecast, including the recent 1 yr forecasts, but leads to the counterintuitive result that earthquake risk in Oklahoma is at its highest level in 2018, even though there were one-fifth as many earthquakes as occurred in 2016. Our analysis shows that this is a result of (1) the peculiar characteristics of the declustering algorithm with space-varying and time-varying seismicity rates, (2) the fact that the frequency–magnitude distribution of earthquakes in Oklahoma is not well described by a single b-value, and (3) at later times, seismicity is more spatially diffuse and seismicity rate increases are closer to more populated areas. ITS in Oklahoma may include a combination of swarm-like events with tectonic-style events, which have different frequency–magnitude and aftershock distributions. New algorithms for hazard estimation need to be developed to account for these unique characteristics of ITS.

Forecast of the Pyroclastic Volume by Precursory Seismicity of Merapi Volcano

2019 ◽  
Vol 14 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Masato Iguchi ◽  
Haruhisa Nakamichi ◽  
Kuniaki Miyamoto ◽  
Makoto Shimomura ◽  
I Gusti Made Agung Nandaka ◽  
...  
Keyword(s):  
Seismic Energy ◽  
Volcanic Eruptions ◽  
Pyroclastic Flows ◽  
Energy Calculation ◽  
Cumulative Energy ◽  
Merapi Volcano ◽  
Tectonic Earthquakes ◽  
Order Of Magnitude ◽  
The Difference ◽  
Log Linear

We propose a method to evaluate the potential volume of eruptive material using the seismic energy of volcanic earthquakes prior to eruptions of Merapi volcano. For this analysis, we used well-documented eruptions of Merapi volcano with pyroclastic flows (1994, 1997, 1998, 2001, 2006, and 2010) and the rates and magnitudes of volcano-tectonic A-type, volcano-tectonic B-type, and multiphase earthquakes before each of the eruptions. Using the worldwide database presented by White and McCausland [1], we derived a log-linear formula that describes the upper limit of the potential volume of erupted material estimated from the cumulative seismic energy of distal volcano-tectonic earthquakes. The relationship between the volume of pyroclastic material and the cumulative seismic energy released in 1994, 1997, 1998, 2001, 2006, and 2010 at Merapi volcano is well-approximated by the empirical formula derived from worldwide data within an order of magnitude. It is possible to expand this to other volcanic eruptions with short (< 30 years) inter-eruptive intervals. The difference in the intruded and extruded volumes between intrusions and eruptions, and the selection of the time period for the cumulative energy calculation are problems that still need to be addressed.

scholarly journals A new model of the upper mantle structure beneath the western rim of the East European Craton

2014 ◽  
Vol 6 (1) ◽  
pp. 559-598
Author(s):  
M. Dec ◽  
M. Malinowski ◽  
E. Perchuc
Keyword(s):  
Upper Mantle ◽  
Seismic Velocity ◽  
Seismic Station ◽  
Structural Features ◽  
East European Craton ◽  
P Wave ◽  
Mantle Structure ◽  
Reflected Waves ◽  
East European ◽  
Upper Mantle Structure

Abstract. In this article we present a new 1-D P wave seismic velocity model (called MP1-SUW) of the upper mantle structure beneath the western rim of the East European Craton (EEC) based on the analysis of the earthquakes recorded at the Suwałki (SUW) seismic station located in NE Poland which belongs to the Polish Seismological Network (PLSN). This analysis was carried out due to the fact that in the wavefield recorded at this station we observed a group of reflected waves after expected P410P at epicentral distances 2300–2800 km from SUW station. Although the existing global models represent the first arrivals, they do not represent the full wavefield with all reflected waves because they do not take into account the structural features occurring regionally such as 300 km discontinuity. We perform P wave traveltime analysis using 1-D forward ray-tracing modelling for the distances up to 3000 km. We analysed 249 natural seismic events that were divided into four azimuthal spans with epicentres in the western Mediterranean Sea region (WMSR), the Greece and Turkey region (GTR), the Caucasus region (CR) and the part of the North Atlantic Ridge near the January Mayen Island (JMR). Events from each group were sorted into four seismic sections respectively. The MP1-SUW model documents bottom of the asthenospheric low velocity zone (LVZ) at the depth of 220 km, 335 km discontinuity and the zone with the reduction of P wave velocity atop 410 km discontinuity which is depressed to 440 km depth. The nature of a regionally occurring 300 km boundary here we explained by tracing the ancient subduction regime related to the closure of the Iapetus Ocean, the Rheic Ocean and the Tornquist Sea.

scholarly journals CARPATHIANS

2020 ◽  
pp. 27-37
Author(s):  
S. Verbitsky ◽  
R. Pronishin ◽  
V. Prokopishin ◽  
A. Stetskiv ◽  
M. Chuba ◽  
...  
Keyword(s):  
Seismic Station ◽  
Seismic Energy ◽  
Earthquake Source ◽  
National Academy Of Sciences ◽  
The Carpathians ◽  
Carpathian Region ◽  
Vrancea Zone ◽  
Active Zones ◽  
Maximum Earthquake ◽  
Academy Of Sciences

The article describes seismic observations in the Carpathian region in 2014, which were carried out, as before, by two organizations from two states: in Ukraine – the Seismicity Department of the Carpathian region of the Institute of Geophysics of the National Academy of Sciences of Ukraine, in Moldova – the Seismology Laboratory of the Institute of Geology and Seismology of the Academy of Sciences of Moldova. In Ukraine, 20 stationary digital stations and 3 temporary ones worked in the Dniester energy complex with a processing center in Lviv, in Moldova - six stations with a center in Chisinau. Different programs, local hodo-graphs and magnitudes were used. The consolidated catalog of earthquakes was created in Lviv. A map of epi-centers and a table of the distribution of earthquakes of different classes by region are given. The total number of earthquakes in 2014 was NΣ=81 in the range KP =5.2–14.3 with the interval of hypocenter depths h=1–154 km and the total seismic energy ΣE=2.11·1014 J. Of these, 18 earthquakes with depths h=77–154 km located in the Vrancea zone. The maximum earthquake with KP=14.3 was registered on November 22 in the Precarpathian Trough with hрР=37 km. In the Vrancha mountains the maximum earthquake occurred on March 29 with the KP=12.5 and hрР=136 km. In the Precarpathian and Transcarpathian regions, all earthquakes were weaker. The most powerful event in Transcarpathia was a perceptible earthquake that occurred near the Trostnyk seismic station on November 15 with KP=8.9. The earthquake source is located in the Earth's crust at a depth of h=10 km. The earthquake was felt by the population of the Dyakovo, Trostnyk, Fanchykovo villages with the intensity of 5 and 4–5. In general, in all the seismically active zones of the Carpathians in 2014, there was a slight increase in the level of seismicity compared to that in 2013.

scholarly journals METHODOLOGICAL APPROACHES TO DETERMINING THE STATE OF BLOCK SEISMOGENIC MEDIUM ON THE EXAMPLE OF THE 2008-2011 SEISMIC ACTIVATION IN THE CENTRAL PART OF THE BAIKAL RIFT

2019 ◽  
pp. 4-13
Author(s):  
P. G. Dyadkov ◽  
Y. M. Romanenko ◽  
M. P. Kozlova ◽  
L. V. Tsibizov ◽  
A. A. Duchkova
Keyword(s):  
Energy Release ◽  
Seismic Activity ◽  
Seismic Energy ◽  
B Value ◽  
The State ◽  
Joint Analysis ◽  
Block Medium ◽  
Seismic Regime ◽  
Methodological Approaches ◽  
Epicentral Region

Based on the joint analysis of the seismic regime parameters, such as anomalies of seismic energy release, b-value, seismic activity A10, approaches to assess the state of the block-seismic medium are proposed. The method validation was done for the example of preparation and development of seismic activity in 2008-2011 in the Central part of the Baikal rift, during which there were 2 strong M5.3 earthquakes. It was found that within 2 years before the strong Maximihinskoye Earthquake of 2008 in the Earth's crust of the epicentral region there is a transformation from softening to strengthening (consolidation) of the block medium. At the same time, in the neighboring region (the area of the Svyatoy Nos Peninsula), the opposite nature of the changes is observed.

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