Seismological service

Seismological service – gathering and analysis of instrumental and macroseismic data

The seismological service includes the gathering and analysis of the earthquake instrumental and macroseismic data.

The present equipment of the Seismological Observatory of Faculty Natural Sciences and Mathematics in Skopje allows instrumental registration and location of local earthquakes with Richter local magnitude () to around zero. The minimal magnitude of the earthquakes with maximal epicentral distance (180 arc degrees) that can be registered is about 5.

The data for the earthquakes from all around the world and the corresponding analysis are presented in the Preliminary seismological bulletins. These are included in the international exchange of seismological data. Presently, these bulletins are sent by e-mail to the European Mediterranean Seismological Centre − EMSC(клик за линкот http://www.emsc-csem.org), Bruyères-le-Châtel, Essonne, France, to the International Seismological Centre – ISC (клик за линкот http://www.isc.ac.uk/), Thatcham, Berkshire, Great Britain, as well as to the National Earthquake Information Center - NEIC, (клик за линкот http://earthquake.usgs.gov/regional/neic/), Denver, Colorado, USA. In the first of these centres, the data about the earthquakes occurred in the territory of Republic of Macedonia and the neighboring regions with Richter local magnitude equal or greater than 2 () are sent via e‑mail immediately. These centers, in their own seismological bulletins intended for general use, publish the data and analyzes of all individual seismological institutions. Thus, the reference of the Seismological Observatory in Skopje in the world seismological bulletins is permanent.

The data for the earthquakes occurred in the territory of Republic of Macedonia and the neighbouring regions are analyzed in most details. These data and analysis are presented in the Annual earthquake catalogues. The locations of earthquakes’ epicentres are specially presented in the Epicentral maps.

With its establishment, the Seismological Observatory in Skopje managed to get the macroseismic data for the earthquakes from the territory of the Republic of Macedonia which had been formerly collected by foreign seismological institutions and researchers. Thus, the macroseismic data in the Archive of the observatory cover a period of more than 1500 years ago. In its development, the observatory always used to implement the most up-to-date macroseismic scales and methods. The gathering of the macroseismic data according to such scales was always done through questionnaires compiled at the observatory. Thus, the Mercalli scale (MCS) was used in the period 1957–1966, the Medvedev–Shponhoer–Karnik scale (MSK-64, MSK-1964) with its modifications was used in the period from 1967–2000, and the European macroseismic scale from 1998 (EMS-1998) (клик за линкот http://www.gfz-potsdam.de/portal/gfz/Struktur/Departments/Department+2/sec26/projects/previous_projects/06_seismic_vulnerability_scales_risk/EMS-98/EMS-98_language_versions)) has been being in use since 2001.As it is known, all these scales have a range from I to XII degrees. Further, the MSK-1964 and the EMS-1998 scales take into account the types of building design and the quality of the construction in the descriptions of the intensity degrees, unlike the Mercalli scale.

In a case of a felt earthquake in the territory of Republic of Macedonia, the observatory sends quick reports to the public and to the republic institutions responsible for information and mitigation of the earthquake effects. The quick reports of the observatory include the main information about the felt earthquake: epicentre location, magnitude, intensity and caused damages. According to the public interest, the seismologists from the observatory can give longer interviews in cases of felt earthquakes.

Isoseismal maps are elaborated for earthquakes felt in the territory of Republic of Macedonia, if there are enough macroseismic data available. These maps are then included in the Annual earthquake catalogues, Ten-annual atlases of isoseismal maps and in the Archive of isoseismal maps for the different epicentral areas.

When a stronger earthquake occurs in Republic of Macedonia, the Seismological Observatory in Skopje prepares a separate detailed report, which also includes the results of the scientific research about the earthquake.

The catalogs, epicentral maps and atlases of isoseismal maps for the earthquakes occurred in Republic of Macedonia and neighbouringregions prepared by the observatory are necessary and unavoidable for any serious research related to the seismicity and seismotectonics of the territory of the Republic of Macedonia and neighbouringregions.

The number of such papers of the observatory from its foundation to nowadays is about several hundreds. All together, they present of a huge archive of professional and scientific papers of the staff of the observatory, as well as a valuable seismological data-base.