The Hellenic Seismological Network of Crete (HSNC): validation and results of the 2013 aftershock sequences

G Chatzopoulos,F Vallianatos,I Papadopoulos

doi:10.5194/adgeo-41-65-2016

Abstract

Abstract. The last century, the global urbanization has leaded the majority of population to move into big, metropolitan areas. Small areas on the Earth's surface are being built with tall buildings in areas close to seismogenic zones. Such an area of great importance is the Hellenic arc in Greece. Among the regions with high seismicity is Crete, located on the subduction zone of the Eastern Mediterranean plate underneath the Aegean plate. The Hellenic Seismological Network of Crete (HSNC) has been built to cover the need on continuous monitoring of the regional seismicity in the vicinity of the South Aegean Sea and Crete Island. In the present work, with the use of Z-map software the spatial variability of Magnitude of Completeness (Mc) is calculated from HSNC's manual analysis catalogue of events from the beginning of 2008 till the end of September 2015, supporting the good coverage of HSNC in the area surrounding Crete Island. Furthermore, we discuss the 2013 seismicity when two large earthquakes occurred in the vicinity of Crete Island. The two main shocks and their aftershock sequences have been relocated with the use of HYPOINVERSE earthquake location software. Finally, the quality of seismological stations is addressed using the standard PQLX software.

Highlights

The number and quality of seismological networks in Europe has increased in the past decades
The subduction of the Mediterranean plate under the Aegean plate creates the Benioff zone of intermediate and depth earthquakes, as it has been estimated by seismological studies (McKenzie, 1972; Le Pichon and Angelier, 1979) and it has been revealed by tomographic results (Spakman, 1988; Papazachos and Nolet, 1997)
In the present work in order to present the everyday results and to give evidence of the contribution of Hellenic Seismological Network of Crete (HSNC) in the effort of creation reliable data sets, we show the preliminary results from the analysis of two aftershock sequences

Summary

Introduction

The number and quality of seismological networks in Europe has increased in the past decades. The convergence of the Eastern Mediterranean plate and the Aegean plate at 4 cm yr−1 rate creates a complex tectonic environment (Le Pichon and Angelier, 1979). In this area, more than 60 % of the total seismic energy in Europe is being released with magnitudes up to 8.3 (Papazachos, 1990). The subduction of the Mediterranean plate under the Aegean plate creates the Benioff zone of intermediate and depth earthquakes, as it has been estimated by seismological studies (McKenzie, 1972; Le Pichon and Angelier, 1979) and it has been revealed by tomographic results (Spakman, 1988; Papazachos and Nolet, 1997). Chatzopoulos et al.: HSNC: validation and results on microseismicity and aftershock sequences

The development of the Hellenic Seismological Network of Crete

Coverage of HSNC – Quality of Stations

The aftershock sequences

Findings

Conclusions