Precursory accelerated Benioff strain in the Aegean area

C. Papazachos;  B. Papazachos

doi:10.4401/ag-3597

THE CRITICAL EARTHQUAKE MODEL: OBSERVATIONS IN CRITICAL AREAS OF THE BROADER AEGEAN AREA

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.16532 ◽

2004 ◽

Vol 36 (3) ◽

pp. 1432

Author(s):

M. C. Kourouzidis ◽

G. F. Karakaisis ◽

B. C. Papazachos ◽

C. Makropoulos

Keyword(s):

Release Rate ◽

Crustal Deformation ◽

Time Variation ◽

Surrounding Area ◽

Aegean Area ◽

Critical Areas ◽

Before And After ◽

Earthquake Model ◽

Critical Regions ◽

Benioff Strain

The time variation of the cumulative Benioff strain, S, in several critical regions of past mainshocks which occurred in Greece and surrounding area has been examined, in an attempt to check the validity of the critical point concept. For this reason, data concerning the critical regions of twelve strong mainshocks, which have recently been defined by other scientists, have been used and intermediate-sized earthquakes which occurred before and after each mainshock were collected. It was found that the cumulative seismic crustal deformation released by these intermediate magnitude events was accelerating before all the mainshocks considered, whereas the deformation release rate during the respective postshock periods was, in general, lower than the preshock ones

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P-wave crustal tomography of Greece with use of an accurate two-point ray tracer

Annals of Geophysics ◽

10.4401/ag-3932 ◽

1997 ◽

Vol 40 (1) ◽

Author(s):

G. Drakatos ◽

G. Karantonis ◽

G. N. Stavrakakis

Keyword(s):

Large Scale ◽

Velocity Structure ◽

Three Dimensional ◽

Seismic Energy ◽

Aegean Sea ◽

P Wave ◽

Low Velocity ◽

Aegean Area ◽

Arrival Times ◽

Horizontal Variations

The three-dimensional velocity structure of the crust in the Aegean sea and the surrounding regions (34.0º-42.OºN, 19.0ºE-29.0ºE) is investigated by inversion of about 10000 residuals of arrival times of P-wave from local events. The resulting velocity structure shows strong horizontal variations due to the complicated crustal structure and the variations of crustal thickness. The northern part of the region generally shows high velocities. In the inner part of the volcanic arc (Southern Aegean area), relatively low velocities are observed, suggesting a large-scale absorption of seismic energy as confirmed by the low seismicity of the region. A low velocity zone was observed along the subduction zone of the region, up to a depth of 4 km. The existence of such a zone could be due to granitic or other intrusions in the crust during the uplift of the region during Alpidic orogenesis.

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SEDIMENTOLOGICAL AND GEOCHEMICAL ANALYSIS OF MIOCENE DEPOSITS IN MOSCHOPOTAMOS AREA, IN THE WESTERN PART OF AXIOS-THERMAIKOS BASIN, NW GREECE

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.11738 ◽

2017 ◽

Vol 50 (1) ◽

pp. 374

Author(s):

V. Savva ◽

P. Tserolas ◽

A. Maravelis ◽

N. Bourli ◽

A. Zelilidis

Keyword(s):

Organic Matter ◽

Organic Content ◽

Sieve Analysis ◽

Organic Carbon Content ◽

Geochemical Analysis ◽

Aegean Area ◽

Sedimentary Characteristics ◽

The North ◽

Caco3 Content ◽

North Aegean

A total of 27 samples of the Moschopotamos area lignite-bearing strata were studied in regard of their geochemical and sedimentary characteristics. Organic content and calcium carbonate evaluation, sieve analysis and micropaleontological observations were used and combined to investigate the paleoenvironment and the depositional conditions of the study area. TOC analysis showed that organic matter values range from 0.07% up to 13.42% with an average of ~3.26 %. The high average of organic carbon content indicates a promising basis for the sediments’ source rock potential, inquiring further and thorough examination. CaCO3 measurements present a range between 4% and 23%. A comparison between TOC-CaCO3 content throughout the stratigraphic column presented certain synchronous and inverse trends, due to alterations of the depositional conditions. This study provides new insights for the understanding of the broader Axios-Thermaikos basin, and depositional conditions in the North Aegean area.

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CORRELATIONS OF THE MEAN TIME AND MEAN MAGNITUDE OF ACCELERATING PRESHOCKS WITH THE ORIGIN TIME AND MAGNITUDE OF MAINSHOCK

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.11406 ◽

2017 ◽

Vol 43 (4) ◽

pp. 2154

Author(s):

E. M. Scordilis

Keyword(s):

Standard Deviation ◽

South America ◽

Strain Rate ◽

Central Asia ◽

Earthquake Prediction ◽

Critical Region ◽

Origin Time ◽

The Mean ◽

Benioff Strain ◽

Mean Time

Forty-five preshock sequences preceding corresponding strong (M≥6.4) mainshocks which occurred recently (since 1980) in a variety of seismotectonic regimes (W. Mediterranean, Aegean, Anatolia, California, Japan, Central Asia, South America) have been examined to identify new predictive properties. It has been observed that the mean origin time, , and the mean magnitude, of the accelerating preshocks of each sequence are correlated with the origin time, tc, and the magnitude, M, of the mainshock, respectively. The following relations have been derived: where sa (in Joule ½ /yr.104 Km2 ) is the Benioff strain rate in each preshock (critical) region and σ is the corresponding standard deviation. The possibility for using these relations as constraints in attempts for intermediate term earthquake prediction is discussed.

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Late Helladic IIIA 1 Pottery From Mycenae

The Annual of the British School at Athens ◽

10.1017/s0068245400006110 ◽

1964 ◽

Vol 59 ◽

pp. 241-261 ◽

Cited By ~ 3

Author(s):

Elizabeth French

Keyword(s):

Major Event ◽

Aegean Area ◽

Historical Significance

Whatever absolute dates are to be attached to the L.H. IIIA 1 period, its historical significance is indisputable. At present this significance derives mainly from events outside Greece itself, the fall of Knossos and the disruption in the Aegean area which went before it. On the mainland, although in South Greece no major event can be associated with the period, in Boeotia the fall of the palace at Thebes has been dated to L.H. IIIA 1 and has been a source of much speculation.

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