Title: Journal of Geodynamics

Title: Journal of Geodynamics

ISO Abbreviated Title: J. Geodyn.

JCR Abbreviated Title: J Geodyn

ISSN: 0264-3707

Issues/Year: 8

Journal Country/Territory: England

Language: English

Publisher: Pergamon-Elsevier Science Ltd

Publisher Address: The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, England

Subject Categories:

Geochemistry & Geophysics: Impact Factor 0.627, 32/45 (2000)

Tinti, S. and Piatanesi, A. (1996), Numerical simulations of the tsunami induced by the 1627 earthquake affecting Gargano, southern Italy. Journal of Geodynamics, 21 (2), 141-160.

Full Text: J\J Geo21, 141.pdf

Abstract: A study of the historical tsunami that occurred on 30 July 1627 in Gargano, Apulia, southern Italy, has been conducted by performing numerical simulations based on integrating shallow water equations via a finite-element (FE) technique. The tsunami was generated by an I = XI earthquake which produced severe damage in the Gargano promontory. Macroseismic observations are not sufficient to determine, unambiguously, the epicentre and the generative fault position. In this study we have assumed a dip-slip focal mechanism which is known to be the most effective tsunami generation. Since the source location is uncertain, different simulations have been carried out assuming that the fault is placed on land (two cases) and offshore (two cases). The Adriatic basin facing the northern coast of Gargano has been covered by a triangle-based mesh, with triangle sizes adapted to the variable bathymetry, which proved to be advantageous in describing the irregular coastlines. The available historical observations concerning the tsunami are scarce and chiefly qualitative. Yet, comparing data with the results of the numerical simulations gives some important hints on the position of the genetic fault. Of all the sources studied, the one matching the observations better is the inshore fault causing the uplift of the sea block facing the Lesina lake. Accordingly, at the present stage of research, this fault can be assumed as that responsible for the 1627 earthquake and tsunami.

Keywords: Sea, Scale

Pavlides, S.B. and King, G.C.P. (1998), The 1995 Kozani-Grevena earthquake (N. Greece): An introduction. Journal of Geodynamics, 26 (2-4), 171-173.

Full Text: J\J Geo26, 171.pdf

Mountrakis, D., Pavlides, S., Zouros, N., Astaras, T. and Chatzipetros, A. (1998), Seismic fault geometry and kinematics of the 13 May 1995 Western Macedonia (Greece) earthquake. Journal of Geodynamics, 26 (2-4), 175-196.

Full Text: J\J Geo26, 175.pdf

Abstract: During the devastating earthquake of 13 May 1995, in the Kozani-Grevena area (Western Macedonia, Greece), many surface ruptures formed in the epicentral area. Most of these fractures were due to faulting, but some were secondary ground ruptures and landslides.

Geological field work in the area has shown that the Aliakmon river neotectonic fault consists of several (three or more) fault strands: the Servia, the Rymnio and the Paleochori-Sarakina strands. Using geological criteria, all of these fault strands were judged to be active faults affecting recent (Holocene) deposits and scree. The main new surface fractures caused by the earthquake, and particularly those clearly of tectonic origin, follow systematically the traces of the last two neotectonic fault strands, forming a new fracture line. This tectonic line, trending ENE-WSW (N 70 degrees), coincides with the focal mechanism solution and the satelite image major lineament. Both the geological and instrumental seismological data suggest that the seismogenic fault is a segment of the Aliakmon river neotectonic fault zone situated among the villages of Rymnio, Paleochori, Sarakina, Kentro and Nisi. The total length of the reactivated fault segment is about 30 km long overall and is separated from the non-activated Servia fault segment by a geometrical seismic segment barrier near the village of Goules.

The seismic fault is a normal fault trending ENE-WSW and dipping to NNW, with high angle at the surface and low angle at depth. The majority of the epicentres of the seismic sequence were distributed on the hangingwall of this reactivated fault segment.

Additionaly a series of subparallel antithetic surface fractures, mainly striking E-W or ENE-WSW and dipping to the South, following previous neotectonic strike-slip faults, were reactivated during the earthquake with the geometry of normal faults antithetic to the main seismic fault. The most important of these are the Chromio-Varis-Myrsina fracture line (length 15 km), along the Vourinos corridor dextral strike-slip structure and the Felli fracture line (length 6 km) along the Felli sinistral strike-slip fault.

An interpretation of the geometry and kinematics of the reactivated faults is shown in the proposed geological model with simplified cross sections. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Papanastassiou, D., Drakatos, G., Voulgaris, N. and Stavrakakis, G. (1998), The May 13, 1995, Kozani-Grevena (NW Greece) earthquake: Source study and its tectonic implications. Journal of Geodynamics, 26 (2-4), 233-244.

Full Text: J\J Geo26, 233.pdf

Abstract: At 08: 47 GMT, on May 13, 1995, a strong earthquake of M_s = 6.6 occurred in the NW part of Greece (Western Macedonia) and caused serious damage in the Kozani and Grevena prefectures, but fortunately no fatalities. The maximum observed macroseismic intensity was IX + of the Modified Mercalli scale. The main shock was preceded by several foreshocks and followed by intense aftershock activity lasting several months. The Institute of Geodynamics of the National Observatory of Athens, in order to monitor and study the aftershock activity, installed a seismic network of nine (9) stations operated for a period of 50 days. Thousands of aftershocks were recorded. Based on the analysis of recorded data, a NE-SW trending zone dipping NW is defined. In the field a surface rupture of normal slip was observed, following a NE-SW direction for a length of 8 km with a 4 cm down throw of the NW area. This break was located along a pre-existing minor normal fault, while a main fault system exists 10 km to the SE. The focal mechanism of the main shock shows normal faulting, which is in agreement with the field observations. Moreover focal mechanisms of several well defined aftershocks were computed, showing various types of faulting.

Hatzfeld, D., Karakostas, V., Ziazia, M., Selvaggi, G., Leborgne, S., Berge, C. and Makropoulos, K. (1998), The Kozani-Grevena (Greece) earthquake of May 13, 1995, a seismological study. Journal of Geodynamics, 26 (2-4), 245-254.

Full Text: J\J Geo26, 245.pdf

Abstract: We present a detailed seismological study of the Kozani earthquake. We relocate the mainshock with regional data at depth of 14.2 km beneath the Vourinos massif. We compute the focal mechanism by body waveform modeling at teleseismic distance and find a normal fault striking N240 degrees and dipping 40 degrees toward the NW with a centroid depth of Il km. We installed a dense network of portable seismographs around the epicentral region and located several hundreds of aftershocks. The main cluster of aftershock seismicity defines a plane dipping north at an angle of about 35 degrees, consistent with the main-shock mechanism, while some seismic activity is also seen on an antithetic fault. Our results suggest the active fault plane to be the Deskati fault which dips at a constant angle and therefore branches on the Paleohori fault where surface breaks were observed. We also compute 181 focal mechanisms which mostly show normal faulting.

Meyer, B., Armijo, R., Massonnet, D., de Chabalier, J.B., Delacourt, C., Ruegg, J.C., Achache, J. and Papanastassiou, D. (1998), Results from combining tectonic observations and SAR interferometry for the 1995 Grevena earthquake: A summary. Journal of Geodynamics, 26 (2-4), 255-259.

Full Text: J\J Geo26, 255.pdf

Abstract: Soon after the 1995 Grevena M-s = 6.6 event, we mapped the Palaeochori earth quake fault break. These tectonic observations are combined with the surface displacement held determined with the SAR interferometry to model the fault dislocation at depth. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Papadopoulos, G.A. (1998), An unusual earthquake time cluster in the Greek mainland during May-June 1995. Journal of Geodynamics, 26 (2-4), 261-269.

Full Text: J\J Geo26, 261.pdf

Abstract: During the time interval of 4 May-15 June 1995 four independent mainshocks occurred in the Greek mainland: 4/5/95, M-s, = 5.5; 9/5/95, M-s, = 5.2; 13/5/95, M-s = 6.6; 15/6/95, M-s, = 6.1. The seismicity rate within this 43-day interval is increased by a factor of 34 and 71 with respect to the mean, long-term seismicity for M-s greater than or equal to 5.2 and M-s greater than or equal to 6.1, respectively. In terms of probability, it has been found out that the probability of observing by chance four events of M-s, greater than or equal to 5.2 or two events of M-s, greater than or equal to 6.1 in the Greek mainland is equal to only 7.12×10^-6 and 3.82×10^-4: respectively. These results imply that the observed seismicity has been a non-random time clustering. Similar earthquake time clusters were identified to have occurred in the Greek mainland in 1911 and 1931. A triggering mechanism has been modeled to interprete the earthquake clustering: the first event of the earthquake sequence produces transient stress changes that cause an acceleration to the stress loading, and then to seismic failure, to remote highly prestressed regions. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Keywords: Triggered Seismicity, Skull-Mountain, Aegean Area, California, Landers, Deformation, Nevada, Region, Hazard, Japan

Rogozhin, E.A., Reisner, G.I. and Ioganson, L.I. (1998), Western Macedonia earthquake of 13 May, 1995 (M_s = 6.6) and seismic potential of Northern Greece. Journal of Geodynamics, 26 (2-4), 289-295.

Full Text: J\J Geo26, 289.pdf

Abstract: The Western Macedonia earthquake of 13 May, 1995 occurred within a territory where high seismic hazard was not expected. However, the estimation of the seismic potential of Europe including Northern Greece, conducted earlier in the United Institute of Physics of the Earth RAS, testified to the existence of the seismotectonic situations of predominantly high prognostical M-max in this region. In particular, epicentral zone of Western Macedonia earthquake has prognostical M-max = 6, 7 according to this data. Estimation of seismic potential was performed applying original seismotectonic method. The essence of this method lies in detecting of the hidden analogies in structure and state of the Earth’s crust on detailed level, relevant to the seismic process. To achieve this, a zonation of the vast territories with different tectonic units was performed, according to the seismotectonic settings. The map of the seismotectonic settings has been obtained after performing the complex detailed typification of Earth’s crust on the base of data reflecting the recent structure and state of the Earth’s crust. The types of the Earth’s crust are considered as seismotectonic settings due chosen initial parameters. Comparison of their spatial distribution with seismological data allows to give the prognostical values of M-max to the most of them. Further spreading obtained estimates of M-max in space results in yielding of the zonation of study area according to the seismic potential.

Chatzipetros, A.A., Pavlides, S.B. and Mountrakis, D.M. (1998), Understanding the 13 May 1995 Western Macedonia earthquake: A paleoseismological approach. Journal of Geodynamics, 26 (2-4), 327-339.

Full Text: J\J Geo26, 327.pdf

Abstract: Paleoseismological research by means of trenching in the area that was affected by the Kozani-Grevena strong (M-s = 6.6) earthquake sequence, revealed evidence for past reactivations of the same seismogenic fault. Five trenches were excavated along the Palaeochori-Sarakina part of the fault, in which three surface faulting paleoevents were identified at ca. 8.97, 36.7 and 72.5 ka BP (TL dates). Recurrence interval based on these datings is about 30 ka, which is very long, verifying the ‘low seismicity’ status of the area. On this basis, the 1995 earthquake was an out of sequence event, because the elapse time since the last major event is 8.97 ka instead of 30. Assuming a constant rate of strain accumulation, this would also explain the small amount of surface displacement that was observed during the 1995 earthquake (maximum 18 cm, usually up to 10 cm) in respect to the displacements observed in the trenches (>25cm) for previous paleoevents. (C) 1998 Elsevier Science Ltd. All rights reserved.

Keywords: Greece, Fault

Baskoutas, I.G., Stavrakakis, G.N. and Kalogeras, I.S. (1998), Q factor estimation from the aftershock sequence of the 13 May 1995 Kozani earthquake. Journal of Geodynamics, 26 (2-4), 367-374.

Full Text: J\J Geo26, 367.pdf

Abstract: The single isotropic scattering model has been applied for the estimation of coda Q values for a number of small aftershocks of the Kozani-Grevena 1995 earthquake. The events were recorded by the telemetric network of the Geodynamic Institute of National Observatory of Athens. Coda Q(c) estimations were made for three frequency bands centered at 1 Hz, 2 Hz, and 4 Hz, and for lapse time windows 2t(s) to 100 sec every 20 sec. The coda Q values obtained show a clear dependence of the form Q(c) = Q(0)f(n), while Q(0), and n depend on the lapse time window. Q(0) was found to range from 50 to 160, and increases as lapse time increases. On the contrary, n decreases as lapse time increases and its values range from 1.02 to 0.76 with a tendency to be stable over 80 sec. This lapse time dependence is interpreted as being due to a depth-dependent attenuation. The temporal variation of Q(c) was also examined within a month time period, but although the results show a tendency of temporal variation at of Q(c) at 1 Hz, the case needs more investigation. (C) 1998 Elsevier Science Ltd. All rights reserved.

Keywords: Coda Waves, Lapse-Time, Attenuation, Scattering, Frequency, Region, Lithosphere, Dependence, California, Greece

Theodulidis, N., Lekidis, V., Margaris, B., Papazachos, C., Papaioannou, Ch. and Dimitriu, P. (1998), Seismic hazard assessment and design spectra for the Kozani-Grevena region (Greece) after the earthquake of May 13, 1995. Journal of Geodynamics, 26 (2-4), 375-391.

Full Text: J\J Geo26, 375.pdf

Abstract: The Kozani-Grevena (Greece) destructive earthquake occurred in a region of low seismicity. A considerable amount of strong-motion data was acquired from the permanent strong motion network of the Institute of Engineering Seismology and Earthquake Engineering (ITSAK) as well as from a temporary one installed after the earthquake. On the basis of this data set as well as on the observed macroseismic intensities, local attenuation relations for peak ground acceleration and velocity are proposed. A posteriori seismic hazard analysis is attempted for the affected and surrounding areas in terms of peak ground acceleration, velocity, bracketed duration and spectral acceleration. The analysis shows that the event of May 13, 1995 can be characterized as one with a mean return period of 500 to 1000 years. Relying on the observed spectral-acceleration amplification factors and the expected peak ground acceleration for mean return period of 500 years, region-specific elastic design spectra for the buildings of the Kozani and Grevena prefectures are proposed.

Christaras, B., Dimitriou, An. and Lemoni, Hel. (1998), Soil quality as a factor of the distribution of damages at the meizoseismal area of the Kozani-Grevena 1995 earthquake, in Greece (M_s = 6.6). Journal of Geodynamics, 26 (2-4), 393-411.

Full Text: J\J Geo26, 393.pdf

Abstract: The physical and mechanical properties of the soil formations were related to the damages observed in Kozani and Grevena area, in Northern Greece: after the earthquake of 13th May 1995 (M_s = 6.6). Properties such as grain size distribution, plasticity, shear strength, compression index, permeability and ultrasonic velocity were measured in order to classify the suitability of the soil formations, for urban planning, and correlate their mechanical behaviour with the damages observed in the construction.According to our observations, a great number of recent buildings were damaged also in areas far away from the seismotectonic zones, where silty and clayey soils dominate, presenting very low permeability, low ultrasonic velocity together with high plasticity and compressibility.

Castaldini, D., Genevois, R., Panizza, M., Puccinelli, A., Berti, M. and Simoni, A. (1998), An integrated approach for analysing earthquake-induced surface effects: A case study from the Northern Apennines, Italy. Journal of Geodynamics, 26 (2-4), 413-441.

Full Text: J\J Geo26, 413.pdf

Abstract: This paper illustrates research addressing the subject of the earthquake-induced surface effects by means of a multidisciplinary approach: tectonics, neotectonics, seismology, geology, hydrogeology, geomorphology, soil/rock mechanics have been considered. The research is aimed to verify in areas affected by earthquake-triggered landslides a methodology for the identification of potentially unstable areas. The research was organized according to regional and local scale studies. In order to better emphasise the complexity of the relationships between all the parameters affecting the stability conditions of rock slopes in static and dynamic conditions a new integrated approach, Rock Engineering Systems (RES), was applied in the Northern Apennines. In the paper, the different phases of the research are described in detail and an example of the application of RES method in a sample area is reported. A significant aspect of the study can be seen in its attempt to overcome the exclusively qualitative aspects of research into the relationship between earthquakes and induced surface effects, and to advance the idea of beginning a process by which this interaction can be quantified. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Cello, G., Mazzoli, S. and Tondi, E. (1998), The crustal fault structure responsible for the 1703 earthquake sequence of central Italy. Journal of Geodynamics, 26 (2-4), 443-460.

Full Text: J\J Geo26, 443.pdf

Abstract: An active crustal shear zone has been recognized in the central Apennines (Italy) by detailed investigations of the surface fault trace pattern of the axial sectors of the mountain belt. Our data suggest that a 16-18 km thick seismogenic layer rests above the ductile lower part of this shear zone and is affected by an interconnecting Late-Quaternary fault system which includes three main transcurrent (left-lateral) fault sets trending roughly north-south. Several lines of evidence indicate that the central fault set is the seismogenic structure responsible for generating the 1703 seismic sequence of central Italy. Fault slip data, morphotectonic and paleoseismological observations, together with fractal statistics, suggest that coseismic deformation within the epicentral area of the 1703 earthquake sequence is partitioned among a few linked faults, and that the ratio of vertical vs. horizontal slip rates within the active central fault set is about 1: 3. Slip rate estimates also show that recurrence times for 1703 type earthquakes are in the range of a millennium. The seismogenic fault structure of the 1703 earthquake sequence may be viewed as a multiple rupture zone with an immature fractal geometry evolving within a crustal volume which deforms in response to transcurrent motion. The main results of this work support our view that the seismogenic potential of this sector of the Apennines can be evaluated by integrating, into a fractal model, the effects due to higher and lower-rank structural components of the Late Quaternary fault system of central Italy. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Koukouvelas, I.K. (1998), The Egion fault, earthquake-related and long-term deformation, Gulf of Corinth, Greece. Journal of Geodynamics, 26 (2-4), 501-513.

Full Text: J\J Geo26, 501.pdf

Abstract: On 15 July 1995, the Egion earthquake (M_s = 6.2) occurred in the vicinity of Egion, west-central Greece. Macroseismic observations along the 12km long E-W trending Egion fault represent short-term or earthquake-related deformation characterized by fairly straight E-W trending surface ruptures with small displacements that mimic the Egion fault geologic offsets and segmentation. Hanging wall converging slip vectors along the Egion fault are clearly related to fault motions at depth. Furthermore, peak accelerations of the built-up area of Egion amount to 0.54 g, that is double the estimated peak acceleration of the Egion coastal area, showing thus close relation between fault trace and attenuation of the ground motion. The Egion fault, with a total geological throw of 200 m and dips to the north at about 55 degrees, accommodating active tectonic deformation of the Egion area. Its morphotectonic expression reflects long-term deformation in competition with the 1995 earthquake related deformation. The Egion fault is controlling the geomorphic evolution of the Egion area as follows: I) The fault is defining the evolution of fan-deltas (offshore) and the Meganitas river alluvial plain (onshore). 2) The hanging-wall’s greatest subsidence is observed, at the Egion bay, at the central portion of the fault. The Egion bay is located at the central part of the fault showing a strong relationship between the long term slip-rate ratio and the recent coastal morphology. The subsidence gradient or the tectonic activity along the fault is defined by the valley-floor width to valley height index (V-f) of small rivers draining the fault scarp. The Meganitas river course is tilted, when crosses the Egion fault trace, towards the area with the highest subsidence along the fault. 3) Stream incision is more important than slope recession at areas close to the fault trace. All these observations suggest that the Egion fault, which probably hosted the last earthquake, are geomorphically controlling the evolution of a 15 km-long by 5 km-wide zone, fairly similar in dimensions to the surface length of the fault.

Yilmazturk, A. and Burton, P.W. (1999), Earthquake source parameters as inferred from the body waveform modeling, southern Turkey. Journal of Geodynamics, 27 (4-5), 469-499.

Full Text: J\J Geo27, 469.pdf

Abstract: Focal mechanism parameters of some significant earthquakes from southern Turkey have been estimated using either the body waveforms or the first motions of P-waves. It is observed that fault plane solutions derived from first motions may not be well constrained and may often be in error because of poor signal-to-noise ratios at some stations, poorly distributed recording stations in azimuth, lack of recognition of the reversed polarities at some stations, and positions of stations in terms of the crustal velocity structure, focal depth and, hence, take-off angles in the source area. The use of the inversion method introduces a considerable improvement in the focal parameters estimated in previous studies that have been used to construct seismotectonic models in the study area. The focal depths inferred from the inversion of body waveforms for the earthquakes occurring in southwestern Turkey are compatible with those reported by the ISC bulletins and other previous studies while the focal depths of earthquakes from the Antalya Bay are found to be less than those given by different agencies. Waveform inversion of earthquakes that have occurred in and around the Antalya Bay implies a low velocity layer showing azimuthal dependence. Hence, depth of rupture and lateral extent of velocity structure are of importance in the investigation of earthquake faulting process in this area. The source time duration of shallow earthquakes is generally longer than that for the deep focus earthquakes from the Antalya Bay and the Rhodes area. The events with relatively short and simple time functions may be interpreted as low stress drop events relative to the crustal ones.

Loo, H.Y., Gao, X.L., Mikumo, T., Hirahara, K. and Yoshioka, S. (1999), Great earthquake cycles along the Japan Trench and their migrations along the subducted slab with influence on the development of shallow shocks in the North-East China tectonic block. Journal of Geodynamics, 28 (2-3), 175-192.

Full Text: J\J Geo28, 175.pdf

Abstract: It is shown that most intraplate earthquakes (M > 5.0) for the past 100 years beneath the Japan islands and the Japan Sea can be correlated with great events (M greater than or equal to 7.9) that occurred along the Japan Trench and the Sagami Trough. The period of seismic quiescence is about 20 years. The average repeat time is about 64 years for trench events and 80 years for the Sagami Trough shocks. The seismic activity starting from a large trench event appears to migrate laterally and downwards along the subducted Pacific plate by a northern and a southern path. Six cycles of the activity seem to have appeared since 1896 and the time required to complete each down-dip migration cycle ranges between 21 and 30 years. Shallow shocks in the North-China block appear to have a time lag of a few years following a deep shock (similar to 600 km) and seem to represent a passive behaviour. These deep shocks generally seem to be preceded by great shallow shocks (M approximate to 8) on the Pacific Ocean side of the Japan islands, the time lag being 5 to 10 years. On the other hand, shallow shocks, occurring along the Fossa Magna fault on the west side of Japan are not part of the earthquake migration; these shocks are characterized mainly by eastward underthrusting, different from earthquakes occurring along the subducted Pacific plate with right lateral sli The seismicity described supports the assumption that subducted plates are visco-plasto-elastic and may be understood with the aid of numerical results showing that compositional density contrasts lead to co-seismic gravity potential release at the focus, governing both the development and the downward migration of earthquakes along the subducted plate.