SEISMIC ZONES AND SEISMICITY OF THE TERRITORY OF THE REPUBLIC OF NORTH MACEDONIA

Main neotectonic regions in the territory of the Republic of Macedonia are the Vardar zone, West Macedonia and East Macedonia. These regions, being developed within major, regional tectonic units, are permanently uplifting with different intensities. They also show differences in the seismic activity, which is the reason to treat them as separate seismic zones, named with the same names. Debar epicentral area belongs to the West Macedonia seismic zone. This epicentral area is presented by the sinking of Drim graben (valley), crisscrossed by neotectonic faults which coused strong earthquake in 1967y, with Richter magnitude ML=6.5 and intensity Io=IX degrees EMS–1998 scale. After 1900y several moderate (5.0≤ML≤5.9) and light (4.0≤ML≤4.9) and lot of small earthquakes with magnitude ML ≤3.9 are also observed. According to all instrumental data, our latest investigation of seismic activity parameters for this epicentral area pointed out the activity of Elbasan-Debar fault.

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Seismicity, tectonism, and surface faulting in the western United States during historic time

Bulletin of the Seismological Society of America ◽

10.1785/bssa0560051105 ◽

1966 ◽

Vol 56 (5) ◽

pp. 1105-1135 ◽

Cited By ~ 5

Author(s):

Alan Ryall ◽

David B. Slemmons ◽

Larry D. Gedney

Keyword(s):

United States ◽

Seismic Activity ◽

Western United States ◽

Seismic Zone ◽

Seismicity Pattern ◽

Seismic Zones ◽

Historic Time ◽

Before And After ◽

High Level ◽

Large Earthquakes

Abstract Maps of tectonic flux are presented for the conterminous United States west of longitude 109°W, for periods of time before and after 1932, and for the entire historic period through 1961. The most active continuous seismic zone in this region during historic time extended over 750 km, from a point off the California coast near Ventura to Winnemucca in north-central Nevada. Although this zone is characterized by a discontinuous line of historic surface faulting, it is neither sharply defined by, nor closely related to structures along its path that are generally considered to be the major tectonic elements of the region. The broad areal extent of this, and five other active zones, suggests that the tectonic processes causing earthquakes and surface faulting in the western United States are distributed over broad regions, and are not confined to geologic or physiographic provinces. Seismicity maps for different periods indicate that seismic activity in some areas has shifted with time. Within major seismic zones, gaps in the seismicity pattern are filled in by successive large earthquakes. Recurrence curves support a high level of activity for the Ventura-Winnemucca zone, and they indicate a lower rate of activity for the San Andreas fault zone than for other areas in the region studied. Recurrence curves for the central California area indicate that the rate of activity in a given region may remain practically constant over periods at least as long as a century, whether or not large earthquakes occur in the region during those periods. There appears to be a general correlation between observed shear or slippage, and the seismicity of any given region. Based on these results, it is proposed that, where historic faulting has occurred in areas with little or no historic seismic activity, such faulting is due to the propagation of fractures into the inactive areas from adjoining seismic zones.

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EMPIRICAL RELATIONS OF SEISMIC MOMENT AND EARTHQUAKE MOMENT MAGNITUDE TO EARTHQUAKE LOCAL MAGNITUDE FOR THE VARDAR AND WEST MACEDONIA SEISMIC ZONES

Contributions Section of Natural Mathematical and Biotechnical Sciences ◽

10.20903/csnmbs.masa.2006.27.1-2.8 ◽

2017 ◽

Vol 27 (1-2) ◽

Author(s):

Vera Čejkovska

Keyword(s):

Scaling Law ◽

Source Model ◽

Seismic Zone ◽

Dislocation Source ◽

Republic Of Macedonia ◽

Seismic Zones ◽

Empirical Relations ◽

Short Period ◽

Wide Range ◽

The Republic

A b s t r a c t: Seismic moments (M0) of 79 earthquakes which ed in the Vardar and West Macedonia seismic zones on the territory of the Republic of Macedonia and neighbouring regions within the period 1992–2002 were obtained by inversion of the amplitude spectra of the vertical components of the short-period shear Sg and Lg surface waves, digitally recorded on the electromagnetic short-period SS-1 and wide-range WR-1 Kinemetrics seismometers at the stations in Skopje (SKO), Ohrid (OHR), Valandovo (VAY), Bitola (BIA) and Kriva Palanka (KPJ). The inversion was done on the Brune dislocation source model and a proper model of the medium. The data used included earthquake local magnitudes (ML) between 1.5 and 5.2, for the Vardar seismic zone, and between 1.4 and 5.2, for the West Macedonia seismic zone. Moment magnitudes (MW) of the earthquakes were calculated using the Kanamori formula. Empirical M0 – ML and MW – ML relations were obtained, the first of the kind for seismic zones in the territory of the Republic of Macedonia. The results also appointed to a differentiation between classes of small and middle-sized earthquakes at ML = 5.2 and to a change in the scaling law of the small earthquakes at ML ≈ 3.0 – 3.5 or M0 ≈ 6·1013 – 1.5·1014 N·m.

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Analysis of soil radon data in earthquake precursory studies

Annals of Geophysics ◽

10.4401/ag-6513 ◽

2014 ◽

Vol 57 (5) ◽

Author(s):

Hari Prasad Jaishi ◽

Sanjay Singh ◽

Raghavendra Prasad Tiwari ◽

Ramesh Chandra Tiwari

Keyword(s):

Statistical Analysis ◽

Multiple Regression ◽

Radon Concentration ◽

Seismic Activity ◽

Meteorological Parameters ◽

Regression Method ◽

Seismic Zone ◽

Type Ii ◽

Soil Radon ◽

Multiple Regression Method

<p>Soil radon data were recorded at two selected sites along Mat fault in Mizoram (India), which lies in the highest seismic zone in India. The study was carried out during July 2011 to May 2013 using LR-115 Type II films. Precursory changes in radon concentration were observed prior to some earthquakes that occurred around the measuring sites. Positive correlation was found between the measured radon data and the seismic activity in the region. Statistical analysis of the radon data together with the meteorological parameters was done using Multiple Regression Method. Results obtained show that the method employed was useful for removing the effect of meteorological parameters and to identify radon maxima possibly caused by seismic activity.</p>

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Structural Design of Skyscrapers Susceptible to Seismic Activity and Soil Liquefaction

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.e6527.018520 ◽

2020 ◽

Vol 8 (5) ◽

pp. 2546-2554

Keyword(s):

Structural Design ◽

Seismic Activity ◽

Soil Liquefaction ◽

Andaman Sea ◽

Seismic Loads ◽

Seismic Zone ◽

Safety Measures ◽

High Rise ◽

Ground Condition ◽

High Chance

The design of skyscrapers involves lot of aspects such as the building must withstand heavy dead loads, should have safety measures against fire, floors must be easily accessible, and should have resistant against wind and seismic loads that can be detrimental to the safety of the skyscraper. Pile foundations are usually adopted for high rise buildings and when it is combined with raft slab they ensure that the problems of differential settlement are taken care of. In this paper the scenario of designing a skyscraper in seismic zone that is prone to earthquakes and the ground condition is such that it is located in vicinity of sea. Andaman and Nicobar isle is one similar place it falls under Zone V as per Indian Standards, hence prone to seismic activity and since it is surrounded by Bay of Bengal and Andaman sea, when seismic activity occurs there is a high chance of soil liquefaction to occur hence proper structural designs should be embraced.

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State of stress in central and eastern North American seismic zones

10.26686/wgtn.13792391.v1 ◽

2021 ◽

Author(s):

S Mazzotti ◽

John Townend

Keyword(s):

Local Stress ◽

Seismic Zone ◽

Postglacial Rebound ◽

Long Wavelength ◽

Seismic Zones ◽

The North ◽

State Of Stress ◽

Perturbation Source ◽

Horizontal Compressive Stress ◽

Hb S

We use a Bayesian analysis to determine the state of stress from focal mechanisms in ten seismic zones in central and eastern North America and compare it with regional stress inferred from borehole measurements. Comparisons of the seismologically determined azimuth of the maximum horizontal compressive stress (S HS ) with that determined from boreholes (S HB ) exhibit a bimodal pattern: In four zones, the S HS and regional S HB orientations are closely parallel, whereas in the Charlevoix, Lower St. Lawrence, and Central Virginia zones, the S HS azimuth shows a statistically significant 30°-50° clockwise rotation relative to the regional S HB azimuth. This pattern is exemplified by the northwest and southeast seismicity clusters in Charlevoix, which yield S HS orientations strictly parallel and strongly oblique, respectively, to the regional S HB trend. Similar ~30° clockwise rotations are found for the North Appalachian zone and for the 2003 Bardwell earthquake sequence north of the New Madrid zone. The S HB /S HS rotations occur over 20-100 km in each seismic zone, but they are observed in zones separated by distances of up to 1500 km. A possible mechanism for the stress rotations may be the interaction between a long-wavelength stress perturbation source, such as postglacial rebound, and local stress concentrators, such as low-friction faults. The latter would allow low-magnitude (<10 MPa) postglacial rebound stresses to locally perturb the preexisting stress field in some seismic zones, whereas postglacial rebound stresses have little effect on the intraplate state of stress in general. © 2010 Geological Society of America.

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Historical and recent seismic activity in South Carolina

Bulletin of the Seismological Society of America ◽

10.1785/bssa0620030851 ◽

1972 ◽

Vol 62 (3) ◽

pp. 851-864 ◽

Cited By ~ 3

Author(s):

G. A. Bollinger

Keyword(s):

South Carolina ◽

Seismic Activity ◽

B Value ◽

Low Noise ◽

The State ◽

Seismic Zone ◽

Recurrence Relationship ◽

Noise Data ◽

History Of ◽

Felt Area

Abstract The seismic history of South Carolina is dominated by the great Charleston earthquake of August 31, 1886. In addition to having several unusual aspects (region essentially free from shocks for preceding 200 years, large felt area, dual epicenter points, “low intensity zone” in West Virginia), that intensity X event seriously perturbed the seismic regime of the area for at least the following 30 years. Of 438 earthquakes reported to have occurred in the state between 1754 and 1971, 402 have been in the Charleston-Summerville area. The remaining 36 shocks form a southeasterly-trending zone of activity that is transverse to the structural grain of the Appalachians. For the 60 shocks assigned an intensity value (1886-1971), a recurrence relationship between the number of earthquakes “N” of maximum intensity “I0” was found to be log N = 0.52-0.31 I0 for IV ≦ I0 ≦ VIII. This corresponds to a “b” value of 0.5 ± 0.1 in log N versus M relationship assuming M = 1 + (2/3)I0. These data suggest a frequency of seismic activity comparable to that reported for the New Madrid seismic zone. Three months of microearthquake monitoring in the Charleston area during the summer of 1971 yielded 505 hr of low-noise data. Sixty-one earthquakes, primarily in swarm occurrence, were recorded. An h value of 1.8 ± 0.5 was determined for these microshock events. This value is similar to that previously observed for a swarm sequence in New Jersey. Four shocks occurred in the state during 1971. Three of these events (May 19, July 31, August 11) were in the central part of the state near Orangeburg, while the third event (July 13) was near Seneca in northwestern South Carolina. All three events had 3.0 < ML < 4.0. Similar episodes of three or four shocks in 1 year happened in 1956 and again in 1965. The Orangeburg area had, according to historical data, been previously free of earthquake epicenters.

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"Real time analysis" of the ion density measured by the satellite DEMETER in relation with the seismic activity

Natural Hazards and Earth System Science ◽

10.5194/nhess-12-2957-2012 ◽

2012 ◽

Vol 12 (9) ◽

pp. 2957-2963 ◽

Cited By ~ 14

Author(s):

M. Li ◽

M. Parrot

Keyword(s):

Seismic Activity ◽

False Alarms ◽

Seismic Zone ◽

Data Set ◽

Ion Density ◽

Real Time Analysis ◽

Number Of False Alarms ◽

Future Earthquake ◽

Automatic Search ◽

Seismic Area

Abstract. This paper is related to the study of the ion density recorded by the low altitude satellite DEMETER. In a first time there is an automatic search for ionospheric perturbations in the complete satellite data set of ion densities. Then perturbations due to known ionospheric phenomena (for example, solar activity) are eliminated as well as perturbations not above a seismic zone. In a second time, there is a search to know if each selected perturbation corresponds to a future earthquake. The earthquakes have been classified depending on their magnitude and depth. This attempt to predict earthquakes of course generates false alarms and wrong detections. The results of this statistical analysis are presented as function of various parameters. It is shown that the number of false alarms is very important, because the ionosphere has variations not only linked to the seismic activity. The number of wrong detections is also important and can be explained by the fact that the satellite is above a seismic area only a few minutes per day and we do not expect continuous perturbations from a given earthquake. The more important results of this study is that the ratio between detected earthquakes and earthquakes to be detected increases with the magnitude of the earthquakes which intuitively makes sense.

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State of stress in central and eastern North American seismic zones

10.26686/wgtn.13792391 ◽

2021 ◽

Author(s):

S Mazzotti ◽

John Townend

Keyword(s):

Local Stress ◽

Seismic Zone ◽

Postglacial Rebound ◽

Long Wavelength ◽

Seismic Zones ◽

The North ◽

State Of Stress ◽

Perturbation Source ◽

Horizontal Compressive Stress ◽

Hb S

We use a Bayesian analysis to determine the state of stress from focal mechanisms in ten seismic zones in central and eastern North America and compare it with regional stress inferred from borehole measurements. Comparisons of the seismologically determined azimuth of the maximum horizontal compressive stress (S HS ) with that determined from boreholes (S HB ) exhibit a bimodal pattern: In four zones, the S HS and regional S HB orientations are closely parallel, whereas in the Charlevoix, Lower St. Lawrence, and Central Virginia zones, the S HS azimuth shows a statistically significant 30°-50° clockwise rotation relative to the regional S HB azimuth. This pattern is exemplified by the northwest and southeast seismicity clusters in Charlevoix, which yield S HS orientations strictly parallel and strongly oblique, respectively, to the regional S HB trend. Similar ~30° clockwise rotations are found for the North Appalachian zone and for the 2003 Bardwell earthquake sequence north of the New Madrid zone. The S HB /S HS rotations occur over 20-100 km in each seismic zone, but they are observed in zones separated by distances of up to 1500 km. A possible mechanism for the stress rotations may be the interaction between a long-wavelength stress perturbation source, such as postglacial rebound, and local stress concentrators, such as low-friction faults. The latter would allow low-magnitude (<10 MPa) postglacial rebound stresses to locally perturb the preexisting stress field in some seismic zones, whereas postglacial rebound stresses have little effect on the intraplate state of stress in general. © 2010 Geological Society of America.

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Тhe Need of Professional Social Work in Overcoming Social Problems and Social Exclusion of Children in the Process of Education

European Journal of Social Sciences ◽

10.26417/ejss-2019.v2i1-57 ◽

2019 ◽

Vol 2 (1) ◽

pp. 63

Author(s):

Svetlana Trbojevik ◽

Sunchica Dimitrijoska ◽

Vladimir Ilievski

Keyword(s):

Secondary Schools ◽

Social Exclusion ◽

Personal Development ◽

Social Problems ◽

Community Services ◽

Professional School ◽

Main Role ◽

The Law ◽

The Republic ◽

Professional Assistance

School going children face numerous social problems such as peer violence, a social behavior, educational neglect, dropout from regular education, committed crimes, and social exclusion. Inevitably, these problems can have devastating effects on adequate social functioning and personal development of children and can hinder their future potentials and wellbeing. Findings presented in this article are generated from two separate researches related to social exclusion and social problems encountered by children in primary and secondary schools in the Republic of North Macedonia. In general, prevalent problems of children are related to bulling, addictions, and conflicts with caregivers and social surrounding, whereas, social exclusion is more prevalent among Roma children. Problems of such nature require appropriate professional assistance and support. The school teams for professional support of children are mainly composed of psychologist and pedagogues. Nonetheless, the above mentioned problems require involvement of other team members such as social workers and special educators. Equipping professional school teams with adequate staff is enabled by the Law on primary education, whereas the Law on secondary education requires additional amendments in order to ensure possibilities for employment of social worker in the secondary schools. Their main role is to provide professional assistance and support to children and their parents on how to utilize the available community services for mitigating prevailing socioeconomic difficulties and for improvement of learning capacities and results of children coping with different problems.

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