Hellenic National Tsunami Warning Centre

History of the HL-NTWC

1892

Establishment of the Greek Seismological Service (today National Observatory of Athens-Institute of Geodynamics, NOA-IG).

1992-1995

NOA-IG was partner at the first pan-European GITEC tsunami research project.

1996-1998

NOA-IG was partner at the pan-European GITEC-TWO tsunami research project.
In the frame of GITEC-TWO a very first effort was made for the design and development of an experimental, telemetric tsunami warning system focusing in the western segment of the Hellenic Arc. The local system comprised a number of new seismic stations, two tide-gauges of pressure type, and an acquisition unit installed at the premises of NOA in Athens for collecting and archiving data (Papadopoulos, 2003a.). Although this vision survived only for a while beyond the life of GITEC-TWO, it was revitalized after the devastating Indian Ocean tsunami of 2004 with the development of a national tsunami warning system.

2005

June: The IOC/UNESCO country-member delegations (Paris, June 2005) decided to establish the North-Eastern Atlantic, Mediterranean and connected seas Tsunami Warning System (NEAMTWS).
Nov.: Establishment of the Intergovernmental Coordination Group (ICG) of NEAMTWS with NOA-IG representing Greece which was one of the founding country-members.

2010

Sept.: The HL-NTWC was officially established by national law.

2012

28th August: The HL-NTWC was declared as operational for a 24/7 tsunami monitoring and alerting service for Greece and the eastern Mediterranean Sea, providing confidential warning messages to the General Secretariat for Civil Protection in Greece (GSCP) which has the responsibility for the downstream component of the system and the dissemination of warning messages. Since then the HL-NTWC acted also as Candidate Tsunami Service Provider in the framework of the NEAMTWS/IOC/UNESCO providing the tsunami messages also to several subscribers by following the requirements, functions and other standards established and adopted by the ICG/NEAMTWS/IOC/ UNESCO. The recipients of tsunami messages from HL-NTWC include relevant authorities in several countries in Europe and in the Mediterranean, the Emergency Response Coordination Centre (ERCC) of EU in Brussels, the IOC/UNESCO (Paris), the Joint Research Centre (JRC) of EC in Ispra and other tsunami warning centres of NEAMTWS.

2013

Apr.: The national tide-gauge network started to build-up with the installation of three stations donated by JRC/EC. The number of stations increased drastically in the next years with the support by various sources.
Dec.: Establishment of a local earthquake and tsunami warning system in Rhodes Isl., SE Aegean Sea, Greece, with the support of the NEARTOWARN preparedness project supported by DG-ECHO/EC.

2017

27th June: The accreditation procedure completed with the Accreditation Ceremony organized during the General Assembly of IOC/UNESCO in Paris, where the four centres accredited (CENALT, INGV, KOERI, NOA-IG) were represented.

2025

31st March: The use of fax, one of HL-NTWC's three alternative means of transmission of tsunami warning messages was terminated. This decision was made after the use of fax was abolished in the Greek public sector effective January 1st, 2021 (article 99 of Greek law 4727/2020), and followng IOC-UNESCO's decision shared via IOC Circular Letter No 3006, to cease the use of fax transmissions of tsunami information products by Tsunami Service Providers by 31 March 2025. HL-NTWC currently transmits tsunami information through the other two alternative/redundant communication means: email and the Global Telecommunication System (GTS).