scholarly journals Glacial rumblings from Jakobshavn ice stream, Greenland

2009 ◽  
Vol 55 (191) ◽  
pp. 389-399 ◽  
Author(s):  
J.A. Rial ◽  
C. Tang ◽  
K. Steffen
Keyword(s):  
Seismic Activity ◽  
Seismic Energy ◽  
Seismic Events ◽  
Earthquake Activity ◽  
Mass Wasting ◽  
Close Inspection ◽  
Seismic Amplitude ◽  
Ice Stream ◽  
Long Duration ◽  
Seismographic Network

AbstractThe steep increase in Greenland’s glacial earthquake activity detected by the Global Seismographic Network since the late 1990s suggests that a close inspection of these events might provide clues to the nature and origin of such seismic activity. Here we discuss the detection of large, unexpected seismic events of extraordinarily long duration (10–40 min) occurring about once every 2 days, and localized in the ice stream that feeds the Earth’s fastest-moving glacier (Jakobshavn Isbræ) from the east. These ‘glacial rumblings’ represent an ice-mass wasting process that is greater and more frequent than glacial earthquakes have suggested. Probably triggered by calving, the rumblings are all very similar regardless of duration, and all end with a sharp, earthquake-like event in which the largest seismic amplitude is in the rumbling and that might signal the collapse of large ice masses upstream. By calculating the total amount of seismic energy released as rumblings, we estimate that the maximum seasonal amount of ice moved seismogenically down the ice stream is up to 12 km3, or ∼30% of the average annual iceberg discharge in Jakobshavn.

scholarly journals The recent instrumental seismicity of Syria and its implications

2018 ◽  
Vol 57 (2) ◽  
Author(s):  
Mohamad Khir Abdul-Wahed ◽  
Jamal Asfahani
Keyword(s):  
Seismic Activity ◽  
Current Knowledge ◽  
Active Faults ◽  
Historical Seismicity ◽  
Focal Mechanisms ◽  
Seismic Events ◽  
Earthquake Activity ◽  
Return Periods ◽  
Cluster Type ◽  
Large Earthquakes

This contribution is an attempt to enlarge the current knowledge about the recent instrumental seismicity, recorded during the period 1995- 2012 by the Syrian national seismological network, as well as the seismotectonic settings in Syria. The recent instrumental seismicity has shown that the earthquake activity has produced a little number of low magnitude events. Consequently, it indicates that this activity is actually passing through a relative quiescence in comparison with the historical seismicity. The correlation between the instrumental seismicity and the seismotectonic features was performed by analyzing spatial distributions of seismic events and focal mechanisms of some strongest events. The current results, allow observing many types of the seismic activity as follows: Swarm-type, Cluster- type, and Occasional-type, which could improve the understanding of the behavior of the seismically active faults. The long return periods of large earthquakes (M?5) and the shortness of instrumental seismicity, prevent us to completely characterize the seismic activity and to discover all the active faults in the country.

Basic principles for building seismic monitoring systems in rockburst-hazardous coal seam mining

2021 ◽  
pp. 8-12
Author(s):  
E. E. Razumov ◽  
◽  
S. M. Prostov ◽  
G. D. Rukavishnikov ◽  
S. N. Mulev ◽  
...  
Keyword(s):  
Seismic Activity ◽  
Average Energy ◽  
Seismic Monitoring ◽  
Acoustic Properties ◽  
Signal Frequency ◽  
Monitoring Systems ◽  
Seismic Events ◽  
Seismic Monitoring Systems ◽  
Seismic Sensors ◽  
Seam Mining

The main directions of development of seismic monitoring systems in underground mineral mining are analyzed. The expediency of passive registration of natural seismic activity is proved, which provides prediction of geodynamic phenomena by locating the centers of seismic events and determining their energy level. The methods of active seismic monitoring (seismic tomography, cross-borehole survey, recording of seismic signal from a rock-breaking tool) are technically more difficult to implement. The promising methods for processing seismic information are geolocation, neural network technology, cluster analysis, and integration with numerical stress–strain analysis of and changes in acoustic properties of rock mass. The configuration of the platform developed at VNIMI and the GITS seismic monitoring system, which includes from 6 to 12 three-component seismic sensors installed permanently in wells or on pedestals, is described. The detailed layouts of seismic sensors at recording points and in gateways in extraction panels are presented. The main technical characteristics of GITS are given: the signal frequency range is 0.1–1000 Hz, the minimum recorded signal level is 0.01 mV. The main test data of GITS in Komsomolskaya mine of Vorkutaugol are described: the average annual levels of seismic activity and energy of seismic events are found to be relatively stable; the relationship between seismic event with the maximum total energy and the alternating increment in the relative criterion is defined, and the local increase in the average energy of a single event in time from the moment the main roof caving is identified. Aimed to substantiate the regional and local prediction criteria of probability of geodynamic events caused by confining pressure, VNIMI implements integrated research in mines in different regions.

Wavelet analysis of the temporal-spatial distribution in the Eurasia seismic belt

2017 ◽  
Vol 15 (03) ◽  
pp. 1750018 ◽  
Author(s):  
Wenfeng Zheng ◽  
Xiaolu Li ◽  
Lirong Yin ◽  
Zhengtong Yin ◽  
Bo Yang ◽  
...  
Keyword(s):  
Fault Zone ◽  
Compact Support ◽  
Large Scale ◽  
Temporal Distribution ◽  
Seismic Energy ◽  
Research Area ◽  
Earthquake Activity ◽  
Seismic Zone ◽  
Seismic Belt ◽  
Earthquake Fault

Due to the growing frequency of earthquakes, safeties of human lives and properties are facing serious threats. However, the research in the field of spatial-temporal distribution of earthquake is quite a few. In this paper, we use wavelet model to analyze the spatial-temporal distribution of earthquakes. Because the spatial-temporal distribution of earthquake activity is closely related to the distribution of the earthquake fault zone, we analyze large-scale earthquake clusters by selecting the Eurasia seismic belt and the surrounding region as the research area. From the perspective of the time domain, the results show that the seismic energy of the earthquake fault zone presences compact support or similar compact support distribution, suggesting that the seismic zone exists a relatively quiet period and active stage. This indicate that the seismic zone is periodical. The period of strong earthquakes above normal and less than normal is different by time changes. The cycles of earthquakes are different due to different regions and different geological and geographical environment.

scholarly journals Seismic activity in the focus of the Uglegorsk earthquakes, Sakhalin Island in relevance to intensive development of coal deposits

2021 ◽  
Author(s):  
Dmitry Kostylev ◽  
Natalya Boginskaya ◽  
Alexander Zakupin
Keyword(s):  
Brown Coal ◽  
Coal Mine ◽  
Seismic Activity ◽  
Large Scale ◽  
Slope Angle ◽  
Sakhalin Island ◽  
Corner Frequency ◽  
Seismic Events ◽  
Velocity Spectrum ◽  
Human Engineering

Abstract Induced seismicity is an increase in seismic activity caused by the human engineering. An example of such activity is the mineral exploration, large water reservoirs construction, exploitation of underground oil and gas storages, etc. The authors studied the seismicity in the Uglegorsky district of Sakhalin region, where the Solntsevskoye brown coal field is located, which is the most promising in the island. Its area is over 100 sq. km, and productive strata of the Verkhneduiskaya formation with a thickness of up to 600 m contains 12 coal seams, 8 of which are working. Active mining of brown coal is carried out at the Solntsevsky coal mine, and blasting operations are performed on a large scale, that, as a result, does not exclude the relation of the seismic process to technogenic seismicity. The earthquake recurrence curves for two decades beginning from 2000 to the present were constructed in the work to compare the characteristics of the seismic regime in the studied area. The difference in the slope angle of recurrence graph during the period of 2011-2020 (the period of the most active development of the Solntsevsky coal mine) from the previous decade is quite significant. The maps of spatiotemporal distribution of seismic events epicenters in the vicinity of Solntsevsky coal mine are constructed. The contraction of zones of seismic events concentration to the mining areas, first of all to the Solntsevsky coal mine, have been found. Such a combination allows us to talk about an increase in seismicity of the region during the last years and change in its character from the natural to a mixed natural and technogenic. The focal mechanisms of the largest earthquakes occurred in the Uglegorsky district have been constructed in order to prove the change in seismicity character and reasons for the earthquake occurrence in the studied area. The mechanisms of seismic events of 2020 are classified as strike-slip faults, that is not character for the most earthquakes on the territory of Sakhalin Island. The authors made an attempt to determine the regularities of the parameters of the produced blasts and earthquakes through dynamic parameters of the seismic events foci by means of studying the frequency content of earthquakes and blasts in order to determine a corner frequency from the focal velocity spectrum.

scholarly journals VÝJIMEČNÉ ZEMĚTŘESENÍ JV. OD POZNANĚ (POLSKO) ZAZNAMENANÉ 6. 1. 2012

2012 ◽  
Vol 19 (1-2) ◽  
Author(s):  
Josef Havíř ◽  
Jana Pazdírková ◽  
Zdeňka Sýkorová
Keyword(s):  
Seismic Activity ◽  
Historical Earthquakes ◽  
Seismic Events ◽  
Local Magnitude ◽  
Sequence Of Events ◽  
The Earth ◽  
Moderate Earthquake ◽  
South Moravia

On January 6, 2012, a moderate earthquake was observed in a region SE of Poznań (local magnitude ML = 3.6 according to Institute of Physics of the Earth, IPE). In this region, there haven‘t been known any historical earthquakes so far, and no natural seismic activity has been observed up to present. Similar rare occurrences of weak and moderate earthquakes were observed in a region near Kaliningrad in 2004 (sequence of events, local magnitude of strongest event being 5.0) and in south Moravia region near Znojmo in 2000 (local magnitude ML = 2.5). These facts show that even in seismically quiet regions occurence of weak to moderate seismic events (with value of magnitude ranging from 3 to 5) could be expected.

scholarly journals Analysis of Petrinja 2020 Earthquake (Croatia) and First 500 Aftershocks >M1.0, Identification of Their Sources and Seismogenic Faults

2021 ◽  
Author(s):  
Tihomir Marjanac ◽  
Marina Čalogović ◽  
Karlo Bermanec ◽  
Ljerka Marjanac
Keyword(s):  
Hanging Wall ◽  
Normal Fault ◽  
Seismic Energy ◽  
Seismic Events ◽  
Surface Cracks ◽  
Surface Phenomena ◽  
Slip Mechanism ◽  
Seismogenic Faults ◽  
Water Activation ◽  
Major Fault

Abstract Strong earthquake of M6.4 stroke Petrinja and neighbouring cities of Sisak and Glina in Croatia on December 29th 2020. It was preceded by two foreshocks of M5.2 and M5.0, and followed by a series of aftershocks of various magnitudes and intensities. We have analysed first 500 earthquakes and aftershocks of > M1.0 which occurred from December 28th 2020 to January 19th 2021, their frequency, focal depths, and coseismic surface phenomena. Correlation of focal depths revealed the source of earthquakes was faulting of hanging wall of a listric normal fault with NW-SE strike and dip towards NE. Major fault seems to have caused earthquakes with only minor magnitudes. The strongest two earthquakes of M6.4 and M5.2 were initiated on synthetic fault, whereas M5.0 earthquake was initiated on an antithetic fault. Almost 50% of all seismic energy of the first 500 analysed seismic events over M1.0 was released on 1 km and 10 km deep hypocentres. Focal mechanisms of major earthquakes and strong fore- and aftershocks indicate dextral-slip mechanism, which is also in accordance with the orientation of surface cracks, land faulting and sand volcano trains. Co-seismic surface phenomena are land cracks and fissures, land faults, sand volcanoes, eruptive springing of ground water, activation of landslides, and formation of dozens of collapse sinkholes which continued to form and grow for about a month following the major earthquake.

scholarly journals Landslides after wildfire: initiation, magnitude, and mobility

Landslides ◽  
2020 ◽  
Vol 17 (11) ◽  
pp. 2631-2641
Author(s):  
Francis K. Rengers ◽  
Luke A. McGuire ◽  
Nina S. Oakley ◽  
Jason W. Kean ◽  
Dennis M. Staley ◽  
...  
Keyword(s):  
Debris Flows ◽  
Rainfall Intensity ◽  
Ground Cover ◽  
First Year ◽  
Mass Wasting ◽  
Soil Infiltration ◽  
Infiltration Capacity ◽  
The Past ◽  
Long Duration ◽  
Southwestern Usa

Abstract In the semiarid Southwestern USA, wildfires are commonly followed by runoff-generated debris flows because wildfires remove vegetation and ground cover, which reduces soil infiltration capacity and increases soil erodibility. At a study site in Southern California, we initially observed runoff-generated debris flows in the first year following fire. However, at the same site three years after the fire, the mass-wasting response to a long-duration rainstorm with high rainfall intensity peaks was shallow landsliding rather than runoff-generated debris flows. Moreover, the same storm caused landslides on unburned hillslopes as well as on slopes burned 5 years prior to the storm and areas burned by successive wildfires, 10 years and 3 years before the rainstorm. The landslide density was the highest on the hillslopes that had burned 3 years beforehand, and the hillslopes burned 5 years prior to the storm had low landslide densities, similar to unburned areas. We also found that reburning (i.e., two wildfires within the past 10 years) had little influence on landslide density. Our results indicate that landscape susceptibility to shallow landslides might return to that of unburned conditions after as little as 5 years of vegetation recovery. Moreover, most of the landslide activity was on steep, equatorial-facing slopes that receive higher solar radiation and had slower rates of vegetation regrowth, which further implicates vegetation as a controlling factor on post-fire landslide susceptibility. Finally, the total volume of sediment mobilized by the year 3 landslides was much smaller than the year 1 runoff-generated debris flows, and the landslides were orders of magnitude less mobile than the runoff-generated debris flows.

scholarly journals Variations of seismic activity caused by the Chandler Wobble

2019 ◽  
Vol 127 ◽  
pp. 03007
Author(s):  
Elena Blagoveshchenskaya ◽  
Evgenia Lyskova ◽  
Konstantin Sannikov
Keyword(s):  
Seismic Activity ◽  
Statistical Parameter ◽  
Specific Rotation ◽  
Temporal Variations ◽  
Chandler Wobble ◽  
Seismic Events ◽  
Slow Rotation ◽  
Global Dynamic ◽  
The Earth ◽  
Rotation Of The Earth

The problem of the correlation of the global dynamic phenomenon “Chandler wobble” with the local dynamics in different parts of the Earth’s crust and lithosphere is wide of the solution. In this study, an attempt was made to approach the solution by analyzing the temporal variations of local seismic activity in the restricted geospace volumes (GSV) within the uniform seismoactive regions. The driver of Chandler wobble is the deep mantle – the most hard and most massive Earth’s layer, whose large inertia tensor value is able to keep up Chandler’s specific rotation of the Earth for a long time. We use the geocentric coordinate system where daily rotation is absent. In this system Chandler wobble is very slow rotation of the Earth around the current equatorial axis (the pole of which is denoted as EP14). Probably, this slow rotation can influence on the seismic events in the GSV. This influence is proposed to determine by the some statistical parameter EP14gsv that indicates the most typical position EP14 on equator when the most part of the earthquakes have occurred in the given GSV. For some geospace volumes the distribution indicates certain longitudes, where the number of seismic events is maximal or minimal.

A Predictive Model of Daily Seismic Activity Induced by Mining, Developed with Data Mining Methods

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Jacek Jakubowski
Keyword(s):  
Data Mining ◽  
Seismic Activity ◽  
Longwall Mining ◽  
Seismic Energy ◽  
Threshold Value ◽  
Classification Model ◽  
Complex Nature ◽  
Basic Characteristics ◽  
Energy Emissions ◽  
Short Term Prediction

AbstractThe article presents the development and evaluation of a predictive classification model of daily seismic energy emissions induced by longwall mining in sector XVI of the Piast coal mine in Poland. The model uses data on tremor energy, basic characteristics of the longwall face and mined output in this sector over the period from July 1987 to March 2011. The predicted binary variable is the occurrence of a daily sum of tremor seismic energies in a longwall that is greater than or equal to the threshold value of 105 J. Three data mining analytical methods were applied: logistic regression,neural networks, and stochastic gradient boosted trees. The boosted trees model was chosen as the best for the purposes of the prediction. The validation sample results showed its good predictive capability, taking the complex nature of the phenomenon into account. This may indicate the applied model’s suitability for a sequential, short-term prediction of mining induced seismic activity.

scholarly journals Towards a standard typology of endogenous landslide seismic sources

2018 ◽  
Author(s):  
Floriane Provost ◽  
Jean-Philippe Malet ◽  
Clément Hibert ◽  
Agnès Helmstetter ◽  
Mathilde Radiguet ◽  
...  
Keyword(s):  
Seismic Activity ◽  
Seismic Waves ◽  
Surface Processes ◽  
Seismic Sources ◽  
Seismic Events ◽  
Earth Surface ◽  
Seismic Signals ◽  
Fluid Circulation ◽  
Source Mechanisms ◽  
Standard Classification

Abstract. In the last decade, numerous studies focused on the analysis of seismic waves generated by Earth surface processes such as landslides. The installation of seismometers on unstable slopes revealed a variety of seismic signals suspected to be generated by slope deformation, weathering of the slope material or fluid circulation. A standard classification for seismic sources generated by unstable slopes needs to be proposed in order to compare the seismic activity of several unstable slopes and identify possible correlation of the seismic activity rate with triggering factors. The objective of this work is to discuss the typology and source mechanisms of seismic events detected at close distances (

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