The Impact of Griva Earthquakes on Structures Damage (original) (raw)
Related papers
Journal of Geodynamics, 1998
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, regionspecific elastic design spectra for the buildings of the Kozani and Grevena prefectures are proposed. 0
The Kozani-Grevena (Greece) earthquake of 13 May 1995 revisited from a detailed seismological study
Bulletin of the Seismological Society of America, 1997
The Kozani earthquake (Ms = 6.6) of 13 May 1995 is the strongest event of the decade in Greece and occurred in a region of low seismic activity. Using regional data and the strong-motion record at the Kozani station, we relocate the mainshock at 40.183° N and 21.660° E, beneath the Vourinos massif at a depth of 14.2 km. We also compute a focal mechanism by body-waveform modeling at teleseismic distance, which confirms a normal mechanism. The most likely plane strikes 240° ± 1° N and dips 40° ± 1° N with a centroid depth of 11 ± 1 km. Modeling of the strong-motion record at Kozani confirms that nucleation started at the eastern termination of the bottom of the fault. Six days after the mainshock, we installed a network of 40 portable seismological stations for one week around the epicentral region. Several thousand aftershocks were recorded, among which we locate 622 with a precision better than 1 km. We compute 181 focal mechanisms that mostly show normal faulting. The aftershock se...
2018
On November 17 2015, a strong earthquake of magnitude M6.4 was nucleated on the Lefkas fault, which is a right lateral strike-slip, almost vertical fault. The earthquake caused high damage at the villages located in the southern part of Lefkas Island and especially at Athani area. The November 2015 earthquake ruptured the southern part of the fault while the M6.2 earthquake of August 2003 ruptured the northern segment. The ground motion on the western coasts of the Island was recorded by the ITSAK network of accelerographs consisting of two broadband triaxial accelerographs working in continuous mode (LEF2 & VAS2) and two triaxial strong motion instruments working in trigger mode. The peak horizontal acceleration values at two sites located in close proximity to the fault was 0.24g at Ag. Nikitas (epicentral distance 14 km) and 0.41g at Chortata (4 km epicentral distance). The analysis of the accelerogram at Chortata and Agios Nikitas clearly show near fault pulse. The earthquake in...
Seismological Research Letters, 1995
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" and dipping 40" toward the NW with a centro'id depth of 11 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", 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 18 1 focal mechanisms which mostly show normal faulting. 0
The Kozani-Grevena (Greece) earthquake of May 13, 1995, a seismological study
Journal of Geodynamics, 1998
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" and dipping 40" toward the NW with a centro'id depth of 11 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", 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 18 1 focal mechanisms which mostly show normal faulting. 0
Mater Thesis, 2014
This thesis presents an investigation of different codes, methodology and techniques used in different countries with the aim to define an appropriate concept for rehabilitation of existing buildings. Chapter 2 is focused on the seismicity of Albania as a country with a high rate of seismicity in which earthquake risk reduction has been an important, on-going socioeconomic concern. A revised catalogue of Albanian earthquakes, from 58 A.D. to 2000, with magnitude Ms>4.5 in the region between 39/N and 43/N and 18.5/E and 21.5/E was used in this study. Ten seismic source zones were used to define the seismicity. The four spectral parameter maps allowed the construction of site-specific Uniform Hazard Spectra for all of Albania and were suggested as the basis of the next version of the KTP-N.2-89 Technical Seismic Regulations to improve earthquake-resistant design code in Albania. In Chapter 3 seismic design requirements or levels are the intended post-earthquake condition of a building; a well-defined point on a scale measuring how much loss is caused by earthquake damage. In addition to casualties, loss may be expressed in terms of property and operational capability. The seismic performance requirement must be achieved through system selection, detailing requirements, design force levels, and permissible drift, based on the Seismic Design Code, considering also the use of the building and the seismicity of the region containing the building site together with the effect of the site conditions. Once the energy demand for a structure is estimated from the earthquake ground motion, the damage potential must be quantified by a combination of response and energy parameters according to Park and Ang, 1985. Within the scope of a specific project the investigation was basically devoted to development of a practical and consistent methodology for structural state diagnosis. Basically, the development procedure is regarded as a specific tool which will provide successful identification of the basic parameters needed for elaboration of an optimal project for revitalization of the structural system, and it is predominantly based on application of the experimental non-destructive tests studied in chapter 5. Chapter 6 is focused on measures for improvement of structural systems in order that they will be capable to withstanding the expected earthquake effects. Decay of the building is usually consequence of weather condition, load effects and foundation settlement, so, building should be safe under normal load and resist the lateral loads without collapse. The types of intervention necessary to enhance the performance of the building can be broadly grouped under the following three categories - Repair, Restoration and Strengthening. Chapter 7 explores a method for damage assessment, in which the mathematical model of an existing building gives the level of damage index. The fragility curves developed inhere represent one of the possible forms of the earthquake intensity – damage to structures relationship. A random point on the fragility curve shows the conditional probability that the damage under an earthquake of a given intensity will exceed a certain damage state.
A revised and extended earthquake catalogue for Greece since 1900
Geophysical Journal International, 1989
An earthquake catalogue for Greece is presented covering the period 1900-1985. It is based on a similar effort attempted a few years ago. The present version contains more than double the number of events, i.e. 4310 events compared with 1806 events, than in the previous papers. It also includes another 1711 events which took place in the region in an Appendix. The accuracy and completeness of the parameters of these shocks were insufficient for inclusion in the main catalogue without affecting the catalogue's homogeneity. For the new entries magnitudes are redetermined using Uppsala's reading as before, whereas the other parameters have been rechecked against local macroseismic information. The completeness of this catalogue varies according to the period of observation, but the lower threshold of completely reported magnitudes has been substantially decreased allowing for more detailed seismicity studies to be performed.