2.2.2. Seismic activity in Albania

houses, and many other losses and destructions in industry and infrastructure, according to the reports. Official damage figures indicated losses of about two billion dollars, 32,900 collapsed or severely damaged buildings, tens of thousands of demolished buildings, numerous other accidents and destructions in 763 commercial and industrial units, and other consequences throughout the country (Georfescu & Ponomis, 2008). Seismological, engineering, and certain disaster management topics were discussed in the postearthquake reconnaissance reports and studies. (Berg, Bolt, Sozen, & Rojahn, 1980). Lessons from the behavior of specific types of structures, The assessment of damages in buildings and infrastructure was provided by both, national and international engineers weeks after the earthquake. Despite the recommendations of the experts for a robust damage-safety assessments for all affected buildings, the order given by the government required that the repairs should be completed just about seven weeks after the earthquake (Craifaleanu, Georgescu, & Dragomir, 2016). government conference was convened on July 4th, 1977, to discuss rebuilding progress; at the time, 14,063 buildings had been assessed as in need of renovation, with only 4,510 having been repaired. Hundreds of thousands of buildings with little or no damage were deemed officially safe after the 1977 earthquake, despite the fact that experts recommended that all tested structures be evaluated further. The evaluation and future retrofit were never completed to the required standard (Craifaleanu, Georgescu, & Dragomir, 2016). However, due in large part to decisions taken in the aftermath of a terrible earthquake that devastated Bucharest on March 4th, 1977, many of Bucharest's pre-1977 structures may be more seismically fragile than we understand. The 1989 opening of the State Archives, combined with painstaking investigation by a team of professionals, revealed a worrying history of latent danger that continues to affect Bucharest residents today, since hurried restorations left severe hidden threats (Georgescu E. , 2003). Modern engineering simulations can forecast a building's performance under various earthquake conditions by taking into account the structure's age, number of floors, structural system, construction materials, proportions of the building, and level of maintenance, but they cannot determine the extent of damage caused by the 1977 earthquake. According to historical research (Georgescu & Pomonis, 2007), the potential impact may be greatly underestimated, despite the feasibility of estimating the damage caused by a future big earthquake in Bucharest and the surrounding area.

 Montenegro Earthquake: M7.0 April 15, 1979 It happened on April 15, 1979, 15 kilometers off the Montenegrin coast between Tivar and Ulqin, with a Richter magnitude of 7.0 and a Mercalli intensity of IX. At the disaster's conclusion, 101 people had been killed in Montenegro, 35 in Albania, and more than 100,000 remained homeless. According to the UNESCO survey, a total of 1487 cultural heritage pieces were destroyed, with nearly half of them being houses and the remaining 40% being churches and other religious resources. Over 1000 cultural monuments, as well as thousands of works of art and priceless collections, were damaged. The cost of damaged cultural property has been estimated to be over 10.5 billion USD (UNESCO , 1984). To cover the disaster's total costs, the government established a legislative fund into which each worker in SFR Yugoslavia contributed 1% of their monthly wage to the reconstruction effort from 1979 to 1989.

All these countries have a history like Albania. They countries in development, affected by earthquakes like Albania, and show us how to overcome natural hazards. Shkupi is the best case that in a poor country, if planned well, can overcome the difficulties and more importantly prevent them.

2.2.2. Seismic activity in Albania Albania is geologically and seismotectonically a very complicated zone. The country is characterized by a developed micro-seismicity with small earthquake, with average number of earthquakes (M = 5.5-5.9) and rarely of large earthquakes rarely (M.6.5). These earthquakes generally occur in three folds (Aliaj, Sulstarova, Peci, & Muco, 2004):

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o Adriatic-Ionian Coast o Belt Peshkopi-Korça o Transverse belt Elbasan-Dibër-Tetovë

Albania is a country which is located on the border between two tectonic plates, that of Eurasian and Adriatic. As a result of the collision of these 2 tiles, it is created an active seismogenic belt which has often generated catastrophic earthquakes such as: Vlora earthquake 16.04.1601 with I0 = 9 degree, Leskovik earthquake 23.12.1919 with I0 = 8-9 degree and M = 6.1, the earthquake of Tepelena 26.11.1920 with I0 = 9 degree and M = 6.4, the earthquake of Durrës on 17-12-1926 with Io = 9 degree and M = 6.2, the earthquake of Llogara 21.11.1930 with I0 = 9 degree and M = 6.1, Peshkopi earthquake 27.08.1942 with I0 = 8-9 degree and M = 6, Lushnja earthquake 01-09-1962 with I0 = 8-9 degree and M = 6.2, Fier earthquake 18.03.1962 with I0 = 8 degree and M = 6.2, the earthquake of 15-04-1979 with epicenter on the Montenegrin coast with I0 = 9-10 degree and M = 7.2 The damage caused by these earthquakes in most cases has been catastrophic. Causing very great damage is related to the fact that these earthquakes have fallen in areas where the population density has been high or constructions made in these areas have not sufficiently considered the seismic risk or it was not properly calculated. Based on the studies done, it is concluded that along the Ionian-Adriatic "seismogenic zone" earthquakes with maximum expected magnitude M = 7-7.5 north of the transverse zone Shkodër-Pejë, while in its south, in the front part, earthquakes with M = 6.0-7.0 can occur. In direction of Tirana, in the east, earthquakes with M = 5.5-6.0 can occur. According to studies in Albania, the recurrence period of an earthquake with M = 5.0 is 3.6 years, of an earthquake with M = 6.0 is 29.1 years, of an earthquake with M = 6.5 is 93.9 years and of an earthquake with M = 7.0 is 505.6 years (Aliaj, Sulstarova, Peci, & Muco, 2004).

 Seismic risk assessment The first seismic map of Albania dates back to 1952 as a product of the work done by experts of the Institute of Sciences and the Ministry of Construction of that time. Since then, studies on assessing the seismic risk in our country has continued with numerous publications to the present day. The map of seismic zoning that is still in force dates back to 1979 (figure 2-4, right). In figure 2-4 (left) is the map of 1963 (Sulstarova, Koçiaj, & Aliaj, 1980).

Figure 2-4 The proposed map of seismic zoning 1963(left) an actual map of seismic zoning 1979 (right) Source: Baballëku, 2014) After the earthquake of April 15, 1979, there was an increase in the assessment of seismic intensities Albania, which were concretized in the map of figure 2-4 (right). Thus, since 1952, seismic risk has been estimated always increasing. A good part of the buildings, object of this study, were built before the year 1979, which means that not only the technical 49

conditions were old, but also the zoning map seismic has had low values of the seismic intensities of the expected earthquakes. Among the recent works (Aliaj, Koçiu, Muço, & Sulstarova, 2010) we can single out the map shown in figure 2-5, in which it is noticed that seismic risk assessments in Albania tend towards an increase in values compared to earlier editions.

Figure 2-5 Seismic risk assessments in Albanai (Source: Aliaj.Sh; Koçiu.S; Muço.B; Sulstarova.E, 2010)

This has come not only as a result of increasing knowledge and experience in the field of seismology, but also as a consequence of the contemporary requirements of the Building Codes in this field (from KTP to Eurocodes). On the other hand, the way the design codes calculate seismic actions has changed over the years. Although the use of "design spectra" for seismic analysis has been present in design codes in our country, the values have been much lower in compared to today. In figure 2-6, the spectra of KTPN.2-78 are presented in the same coordinate system (according to the seismic map of ‘63), KTP-N.289 (according to the seismic map of ‘78) and Eurocode 8, EN 1998-1 (according to the seismic map of ‘04, not in force). The increase in the values of spectral accelerations between periods is clear. If we compare today's demand (for an area with ag = 0.25g) with that of 1978 for an area of intensity VIII point, an increase of about 5 times the spectral acceleration is observed (Baballeku, 2014) for the low-rise buildings. If we refer to the city of Tirana, this change can go up to 10 times, as many of today’s studies give ag values up to 0.25g, while the intensity on the map has were VII in 1979 and VI on the 1963 map.

Figure 2-6 Comparison of spectral accelerations between KTP and EC-8 for Tirana (soil category II by KTP, and B be EC-8)

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