Albanian Broadband Seismological Network design and actual state of the art Edmond DUSHI

Department of Seismology, Institute of Geosciences, Energy, Water & Environment, Polytechnic University of Tirana, Albania

e.dushi@geo.edu.al www.geo.edu.al

ABSTRACT

Though Albania is an earthquake prone country the first seismological station dates in 1968. The local instrumental network was finalized in 1976 counting thirteen seismographic stations. It enabled systematic monitoring of the micro-earthquake activity in the country and led to the discovery of some

characteristic features of the recent seismicity of Albania. Stations have been equipped with passive short period sensors recording on site. Modernization of Albanian Seismological Network (ASN) started in 2002 and continued to 2006. Six broad-band stations are installed and started their normal operation. The actual

design of ASN is based widely on the broad-band instrumentation covering the most seismic active units of the country. Data transmission is done in near real time through satellite telemetry (VSAT) to the central processing center in Tirana. A very broad-band station operates in Tirana as part of Mediterranean

Seismological Network (MEDNET) integrated virtually to ASN.

The actual state of the art of ASN permits contribution to the regional and global seismological database, through its membership in several organizations such as ISC, EMSC, FDSN and IRIS. This paper aims an introduction of ASN giving details on its actual state of the art as part of the global seismological

monitoring framework and contribution.

INTRODUCTION

Geographically Albania is part of the most seismic active region in the whole Mediterranean and the West Eurasia. Tectonic earthquakes are

due to the overall regional geodynamics and tectonic pattern of this region. Especially for Albania involved in a regional continental collision and

dissected by a numerous active, transvers and longitudinal seismic faults (Fig. 1), many strong earthquakes are recorded in the past. Its present

seismic activity is characterized by an intense micro activity, small and medium size earthquakes and seldom by large ones (Fig. 2).

Despite the earthquake hazard, as the major geological risk for this country, detailed information about its seismicity has been available only

after the setting up and continuous operation of the Albanian Seismological Network (ASN), in 1968. The first Albanian seismological station was

settled up in Tirana. In 1976 the complete ASN constitutes of 13 seismological stations was finalized. Instrumentation was on-site, analogues and

short-period, until 2000. During the time, more and more improvements and modernizations, have lead towards a newly configured seismological

network for Albania (Fig. 3, 4).

This presentation aims the describtion of ASN, its actual design along with broadband recording tecnology and satellite telemetred

communication advantages.

NETWORK DESIGN

Albanian Broadband Seismological Network (ASN) comprises 7 stations installed respectively in B. Curri (BCI), Puka (PUK), Peshkopia

(PHP) in the northern Albania; Korça (KBN), Vlora (VLO), Tepelena (TPE) and Saranda (SRN), in the southern Albania (Fig. 4,7). ASN is designed

to comprise both physical and virtual networking. The physical part is based on Libra Satellite Seismographic system, where every remote station

communicate in a dual way with the Central Hub through the satellite telemetry using a predefined spase segment (Fig. 5).

Every remote station is equiped with : BB sensor (Trillium-40 or CMG-40T), Trident digitizer (24 bit ADC), Cygnus Tranceiver (Satellite

Modem) and a Prodeline (1.8 m) antenna dish (parabola) equiped with complet dual transmission kit. ASN have trusted on Nanometrics system

solutions to design its modern network. Very Small Aperture Terminal (VSAT) is choosen for different advantages toward other systems:

Complete freadom of stations installation (even in the most mountinouse and rugh environments like BCI, PUK, PHP)

Exellent data quality (comprising remote correction and sensor calibration, time error autocorrection, near real time broadband data

availability, etc)

Afordable costs

Virtual network consist of near real time seismological signal retreival from different sesimological stations of Neighbor Observation

Networks like INGV- MEDNET & AUTH (Aristotel University of Thesaloniki) by using InterNAQS sofware and Internet connection (Fig. 6, 7). ASN

receives 10 seismological regional stations through InterNAQS.

PERFORMANCE

ASN operates in real time recording permanently local, regional and global earthquake activity but also other types

of non natural seismic events like mane made, quarry blast activities, industrial and/or military explosions and industrial

accidents causing radiative seismic waves. Until the year 2000, equiped with short period sensors and on site analogue

recording system (Seismographs), ASN was not able of recording other then local earthquakes (M > 2.0) up to regional events

(M > 3.0). ASN hardly recorded global events. Analogue recording conditioned the application of signal proccesing and data

computation methodes making use of only empirical relations to compute earthquake parameters.

Operation of the broadband Albanian Seismological Network and Data Processing Center (Fig. 9), has increased the

overall performance and has improved greatly the way of data proccessing. The lower detection threshold has greately

improved decreassing to 1.5 ML and location up to 2.0 ML. Artificial and global events are well recorded (Fig. 8) like other

everyday local and regional tectonic events, and their parameters determined in near real time.

Figure 1 –

Seismotectonic Map of Albania

sc: 1:200 000

Figure 2 –

Seismic Activity of Albania

(1976 to present)

Figure 3 –

Albanian Seismographic Network

Figure 4 –

Albanian broadband Network (ASN)

Figure 5 –

Albanian Libra (VSAT) physical network

Remote BB seismological stations

connected through VSAT to main

Central HUB (Tirana)

Figure 6 –

Connection with neighbor monitoring centers

through virtual InterNAQS

Figure 7 –

State of the Art for the

configuration of ASN

Figure 8 –

Examples of Wave Form records by ASN for Military Explosion of March

15, 2008 (3.5 Ml) event; Septemner 6, 2009 (5.4 Mw) tectonic earthquake

and the global event of April 19, 2013 (6.1 Mw), occured in Kuril Islands

Figure 9 –

ASN Data Processing Center (IGEWE-UPT) in Tirana

Contribution of ASN to Emergency Agency, Scientific comunity and Public

Contribution of ASN to Euro-Mediterranean Seismological Center (EMSC)

Contribution of ASN to Incorporated Research Institutions for Seismology (IRIS)

Contribution of ASN to International Federation of Digital Seismograph Networks (FDSN)

Ackowladgement:

I thank all the Stuff of the Department of Seismology (IGEWE)