The Skopje, Macedonia, Earthquake of 1963 vs. Vrancea, Romania, Earthquake of Long-Run Impacts in Earthquake Engineering

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1 The Skopje, Macedonia, Earthquake of 1963 vs. Vrancea, Romania, Earthquake of Long-Run Impacts in Earthquake Engineering E. S. Georgescu, I. S. Borcia, C. L. Matei, I. G. Craifaleanu, C. S. Dragomir, D. Dobre, F. N. Tanase The National Research and Development Institute URBAN-INCERC, and European Center for Buildings Rehabilitation ECBR, Bucharest, Romania ABSTRACT: The paper evaluates the damage patterns in Skopje in 1963 vs. earthquake engineering knowledge and codes in Romania in 1963, compared with changes in 1970 and after Vrancea 1977 earthquake. Until 1963, Skopje evolved as a Capital, modern city, but without seismic design. In Romania, the last earthquake disaster was in 1940 and the earthquake design code P was endorsed on July 18, In 1977, a Vrancea earthquake caused a disaster in Bucharest and heavy damage in almost half of Romania. The accelerogram of INCERC 1977 was a key to understand impacts of the long-period spectral content of Vrancea motion. The paper compares the lessons in 1963 and 1977, as irregular configurations, soft storey, short-column, pancake collapse, need of local records. On short-term, the 1970 edition of Romanian Code P-13 took into account Skopje lessons, while the initiatives to create EAEE and IZIIS were long-term gains. Keywords: Skopje, 1963; Bucharest, 1977; earthquake design code 1. INTRODUCTION The paper is an attempt to see what we learned and what we should have learned in earthquake engineering during 50 years, since Skopje earthquake. The need to revisit such disasters is manyfold. The local history of earthquakes proved some gaps, as for example, until 1963 Skopje evolved as city with modern architecture, forgetting some 400 years of past earthquakes. In Romania, the effects of earthquakes of 1838, 1829, 1802 and 1738 were already history, but the disaster of 1940 earthquake was not so remote in However, the public memory retained only the collapse of a single highrise building (Carlton), forgetting about some hundreds of the same kind in Bucharest. The Romanian earthquake design code P was endorsed on July 18, The dynamic method for shear force calculation, using response spectra, was considered as an important asset. Such disasters as Skopje 1963 were a remind that irregular configurations, soft storey, short-column may cause pancake or progressive collapse of modern structures and code provisions were added. Although P.13 was revised in 1970, it took more than a decade to put in codes higher values of acceleration, closer to real motions, and Romania Vrancea 1977 earthquake triggered this need. 2. THE SKOPJE, JULY 26, 1963 EARTHQUAKE All sources agree that the Skopje earthquake was the most destructive seismic event in the recent history of Yugoslavian Federation of the time (Milutinovici, 2001; Petrovski, 2003). The casualties were of 1,070 dead and more than 3,300 seriously injured, because of destruction and severe damage to a large number of buildings, public and social facilities, damage to the infrastructure, life-lines. Mass burial was necessary, because of hot season. At urban scale, out of the total building area, with dwelling houses over 80% was destroyed or heavily damaged and about 75% of the inhabitants were left homeless. Some 72% of the major public buildings have been destroyed or heavy damaged. Thus, losses reached about 15% of GNP of that year for all federation (Petrovski, 2003).

2 Concerning the damage of different structural types, from published data and photographs (Ambraseys, 2010; Cismigiu and Titaru, 1964), it was remarked that: - the brick masonry wall structures of buildings suffered more than any other type and were the cause for the larger number of deaths; however, old kiln brick masonry with thick walls and 3-4 storeys of 1900 s were standing, while 6-7 storey masonry buildings with concrete floors collapsed (pancake collapse of mid-rise buildings having walls of bearing masonry and reinforced concrete slabs and collar beams); - in many cases, the mixture of solid brick and hollow bricks, as infilling in frames, as well as the new walls of 25 cm to 15 cm and partition walls of cm collapsed; - amazingly, old adobe structures, particularly those with timber bracing, resisted the shock with some damage but behaved far better than the brick masonry or the mixed structures; - the area did not have strong motion accelerographs or instruments; although a seismological map of Yugoslavia, as well as general information on the seismicity and geological conditions of the Skopje valley existed since 1950, it was not used as criteria for urban planning and construction; - the modern districts of Skopje, said to be in a continuous evolution of urban planning since decades, were damaged, since they were lacking major earthquake disaster prevention strategies; - short and/or captive columns and several cases of partially soft-storey structures, lead to remanent deformations at the limit of condemnation; - structures with tall skeleton, up to 15 storeys, performed considerably better due to the specific frequency content of the earthquake, as they were built more adequate care and, in some cases, the design used wind forces; - ground acceleration during that strong earthquake would have been very high. The emergency operations are already a matter of handbook, while the mass evacuation and temporary accommodation of over persons with special needs was achieved in all Federation. The 69% of the assistance was international (77 countries) and 31% national. Large amounts of tents and prefab houses were received from local and abroad sources. State subsidies for reconstruction were a combination of socialist solidarity funding and free market individual contribution, on 15 to 40 years time. An international contest for Skopje s Master Plan was organized. The project manager for the master plan was appointed by UN in 1964 as Adolf Ciborowski, chief architect of Warsaw, who planned the reconstruction of a city destroyed 85% in the Second World War. For the Master Plan, the jury decided in 1965 to share the prize money in the ratio of 60 to 40 between the conceptual layout plan of the Japanese architect Kenzo Tange, and a Zagreb-based firm. The residential density control, transportation and infrastructures, versus economic development have been main targets. The Star- Trek project of Tange was only in part included in plans and achieved. The reconstruction of Skopje was completed by 1980 (Home, 2007; Lewis, 2010; Lozanovska, 2012; Ladinski, 1995). 3. THE IMPACT OF SKOPJE DISASTER ON ROMANIAN STRUCTURAL AND EARTHQUAKE ENGINEERING CODES OF THE 1970 S The 1963 Skopje earthquake entered in the attention of Romanian authorities, as the national code was just enforced one week ago, after a decade of debates. Skopje was visited by prominent specialists and tehnical papers published (Cismigiu and Titaru, 1964), pointing out: - the damage patterns for masonry and mixed structure buildings, ground floor collapse for relatively new buildings with three stories, sandwich collapse for 3-6 stories; the negative impact of some thinner masonry walls and hollow precast strips slabs, when the building survived near the limit of condemnation; the collapse of the new shell-dome and ground floor damage of exhibition; - the importance to use response spectra in earthquake design and to correlate earthquake damage to soil condition; a comparison of Romanian code of 1963 with the draft Macedonian code of 1964 revealed higher spectral (beta) amplification factors in Romania (3 vs. 1.5) but a larger spectral range in Macedonia (0.3 s vs. 0.5 s), as well as slightly greater minim values of beta (0.6 vs. 0.5); - in the code of 1964, the seismic factors K s for seismic zones were given on three soil categories, from weak to good, as follows: for I=VII (0.025 / / 0.015); for I=VIII (0.05 / 0.04 / 0.03); for I=IX (0.10 / 0.08 / 0.06), rather similar to P.13/63; it was remarked that for very rigid buildings, at

3 I=IX, design forces result 2.5 times lower than in Soviet code; - the near-field amplifications of Skopje, as explanation for stiff structures heavy damage; the need to consider vertical components of motions; the damage of tall and slender structures due to higher modes influence (minarets); - necessity to have instrumental records and a new intensity scale, based on spectral intensity; the Romanian authors presented their proposals on a seismic intensity scale, where the values of maximum ground accelerations were considered as mm/s 2 for I = 6, mm/s 2 for I = 7, mm/s 2 for I = 8 and mm/s 2 for I = 9. Since such input values lead to forces of 4-6 times higher than in design codes based on dynamic calculation, it was presumed and accepted that damping and plastic deformations would reduce the actual load; - use of soft-storey structures to be permitted only with higher design forces, under special design and technology. At the date of endorsement on July 18, 1963, the provisions of the P Romanian Code were comprehensive, taking into account importance classes, constructive provisions on structures and materials types, they made references at vertical forces, nonstructural elements, industrial facilities, checking of elements with stress concentrations etc. This code must be understood in the context of past Romanian earthquakes and developments. After the 1940 earthquake, a first rough seismic zonation was given in MLP Instructions (1942, revised in 1945), referring to the South and East of the country. Until 1963, the provisional seismic design used a lateral force of 5% of weight and a mix of Soviet, USA, German and Italian provisions. The new zonation standard map STAS 2923 was introduced in 1952, and it was changed in 1963; seismic intensity zones and K s design factors corresponded to value in 7 grade, 0.05 in 8 grade and 0.1 in 9 grade. Microzonation maps have been indicated as an alternative to the soil conditions characterization (Georgescu, 2002). Figure 1. The comparison of design spectra of the Yugoslavian Code of 1964 and Romanian Codes of the period Unexpectedly, as compared to I=IX MCS of past assessments, the intensity of Bucharest city was decreased from I= VIII to I = VII on the zonation map of 1963, but the intensity of Focsani epicentral zone was increased by a grade, I = IX. The new map took into account the possible effects of others local sources too (the South of Dobrogea that was not considered seismic in 1952 was re-appreciated in 1963 at VII intensity). The South-West of Banat was reconsidered (Timisoara, Oravita, Moldova Noua I = VII); in the West and North of Transilvania new intensities of I = VII were introduced. As it is depicted in figure 1, the dynamic calculation methods of P relied on a design spectrum β having an amplification factor of 3, with β = 0.9/T formula, limited between 0.6 and 3, with a decrease until Tr = 1.5 s, and with a possible increase of 25-50% to take into account the soil conditions. This curve was based on a Californian-type spectrum. The design loads were calculated applying an increase of 20 to 50 % for flexible structures (factor ψ) (Georgescu, 2002). The lessons of Skopje earthquake have been mentioned as a source of knowledge in the foreword of the new edition of the P13 / 1970 Code, associated to other lessons of worldwide earthquakes occured

4 between 1963 and 1969, including the need for an extended network of accelerometers. Mirroring some influence of the 1964 code (??!!), in the P13-70 Code (figure 1) the spectral β curve amplification was reduced from 3 to 2, with a β = 0.8/T r formula, with a decreasing until T r =1.33 s, with reductions of 20% and increasing of 50% corresponding with foundation soil; seismic forces were increased for the 7 grade zone and diminished for the 9 grade zone, the global seismic coefficients increased or diminished on some construction categories, with the well known and blamed 2% minimum limit of base shear force. Calculation of seismic forces included an increase of 20% to 100% for some types of structures including tall and flexible ones (factor ψ). 4. THE VRANCEA, MARCH 4, 1977 EARTHQUAKE As a result of the 7.2 Richter Vrancea earthquake of March 4, 1977, the damage was accounted for 32,900 collapsed or heavily damaged dwellings, 35,000 homeless families, tens of thousands of damaged properties, other destructions in 763 commercial and industrial units and effects in the whole economy. The human loss data referred to 1,578 people killed, 11,321 people injured, with Bucharest at highest human loss, since 90% of the killed and 67% of the injured were there. A number of highrise apartment buildings (of 7 to 14 storeys) that were constructed in the as reinforced concrete frames designed only for gravity loads collapsed. Official reports state that out of Romania s 40 counties, 23 were strongly affected, with Bucharest recording the highest losses (World Bank, 1978). Some towns and counties located at large distances from the Vrancea source zone suffered heavy damage and casualties in both 1940 and 1977, but in 1977 the cumulative damage effects, especially in pre-war high-rise structures, explains the concentration of damage and casualties in Bucharest (Balan et al, 1982; Berg et al, 1980, Georgescu and Pomonis, 2007 and 2008). The overall picture revealed many collapses and damages virtually similar to Skopje disaster, but in many cases the reason was different: - the vulnerability and sandwich type collapse, total or partial, of 28 buildings with reinforced concrete skeleton and masonry, built before 1940 without seismic design, having inadequate architectural conformation, lacking ductility, with insufficient transversal reinforcement, suffering collapse of the highly loaded columns; - collapse happened, partially, only in case of 3 buildings erected after 1960 and damages to others, especially slender frames; thus, the P.13/1963 code efficacy, was proven, even if some design parameters had lower values; - large panel structures were unscathed. It is well-known the INCERC seismic record of March 4, 1977, made by a Japanese apparatus SMAC- B, that put for the first time in evidence the spectral content of long period seismic motions of Vrancea earthquakes, the considerable duration, the large number of cycles and values of actual accelerations, with important effects of overloading upon flexible structures. The new earthquake resistant design code P.100 was adopted in 1978 and revised in It is significant that the microzonation maps (STAS 8879 series) have been taken out of use, because they did not reflect actual damage. The water table depth influence (the Medvedev concept ) was considered in microzonation maps for some cities too; thus, in Bucharest the most affected area should have been the one on the river meadow and right bank of Dambovita River, but it was in other central area (Georgescu, 2002). After 1977, the main adjustments of the P13-70 design code (which became P100-78) regarded the new values for k s (from 0.07 for degree 6 up to 0.32 for degree 8), which were better correlated with the ground accelerations, passing to values for ψ factors smaller than unity (from 0.15 to 0.35). The β curve (figure 1) had now a branch from zero to the threshold of 1.5 sec, with the formula β=3/t r, bounded by 0.75 and 2, with a decreasing to T r =4.0 sec, with 20% reductions and 30% increases, function of the ground conditions. The new constructive provisions, regarding general ductility conditions and loading limits for columns, shear reinforcement schemes for columns, beams and structural walls boundary elements have been introduced (Georgescu, 2002). A new formula for

5 dimensioning the aseismic joint, function of the seismic lateral displacements of adjacent buildings, taking into account the post-elastic deformations, the storey drift checks, with limit values differentiated by types of masonry and elements, have been provided. It was recommended to design rigid structures, avoiding soft ground floor and to extend the flexible zone on more structure levels too. In spite of the reductions that were imposed, the P Code put emphasis on the need to prevent earthquake damage, which can cost more than the initial investment increase and can generate disasters. Later on, earthquake resistant design codes and zoning maps were improved in 1991 and 1992, with important contributions of INCERC, based on original studies and strong motion data processing (Sandi, 1986; Georgescu, 2002). The latest edition of Seismic Design Code is of The choice of higher or lower spectral amplification factors is still in evolution in Romanian code. Rescue operations started within hours, citizens volunteered for aid, but rescue operations and recovery of corpses lasted for 24 days. The total reported losses account for US$ billion (US$ billion in direct losses and US$ billion in production losses). The analysis of the 1977 earthquake losses was made again in 1992 and resulted in a property loss of 5% of GNP or 1.63% of National Wealth (Georgescu & Kuribayashi, 1992; Georgescu, 2002). In a further analysis, using the total possible loss estimated by the author (US$ billion) and the alternatives of GNP, the range of total possible loss ratio to GDP or GNP in 1977 could range between 13.3% and 21.1%. It is worth of remarking that Romania s losses in 1977 were presumably underestimated in comparison to the scale of damages in other countries, as for instance, the 1963 Skopje and 1979 Montenegro earthquakes in Yugoslavia and the comparison shows that the ratio of 15% loss after the Skopje, 1963 disaster highlights how the size of loss increases when the capital city of small countries is directly affected (Georgescu and Pomonis, 2007, 2008). International assistance in humanitarian and financial terms from the West was extensive, favored by the politics of relative independence of the regime in the 1970 s. A number of 55 countries and 12 organizations provided aid and support (World Bank, 1978). The situation was under control, there was no food or water shortage, epidemics were absent and rescue operations pace was fast; electricity, telephone, radio and television broadcasts have resumed within few hours; transportation networks were operational; the provisional shelters were necessary only in some localities, because the current public investments in urban housing allowed authorities to provide shelter, furniture and goods for the rescued and the homeless from state funds. Two new cemeteries were open in Bucharest, but with individual graves. The demolition and cleaning of collapsed building sites, as well as the repair and strengthening of some high-rise structures started very soon. The collapsed buildings were replaced by reconstructions. However, something went wrong in the mind of the regime leader, thus on March 30, 1977, and then in July, 1977, the Government ordered that the existing structures be maintained or rehabilitated, nominally, but only at the initial aseismic strength level, officially being neglected the great deficiencies and the effect of cumulative damage (Georgescu and Pomonis, 2007; 2008). 5. CONCLUSIONS ON LONG-RUN IMPACTS IN EARTHQUAKE ENGINEERING The specific of strong motions and built stock was different in Skopje earthquake 1963, as compared to Vrancea, Romania, Capital Cities were affected in both cases of 1963 and 1977, but in 1977 Romania was affected by an intermediate source, to a greater country extent. Nevertheless, some impacts are well related in terms of scientific and practical approaches. A period of 50 years is relatively short, but the 1963 and 1977 disasters have long-run impacts in earthquake engineering, urban planning and disaster management. Earthquakes continued to affect Europe after 1963, as the vulnerability is built-in, to a certain extent, in the patterns of development. It was obvious the need of

6 local strong motion records and sound earthquake design, integrated with urban planning. INCERC operates a national network of accelerographs. The Skopje disaster was an opportunity to put in practice some approaches that are now in current use (Petrovski, 2003): - field inspection for classifying the usability of buildings according to the degree of caused damage, with color signs; - mapping of detailed tectonic, geological, seismological, seismotectonic, geophysical and geotechnical parameters; - obtaining seismic microzoning maps to be used directly in the process of physical and urban planning; - implementing codes for seismic design and construction and strengthening of earthquake-damaged buildings. As the striking impacts were of urban nature, the approach was at the hands of urban planners. The urban reconstruction of Skopje after 1963 was a great success in terms of the epoch. The Skopje disaster was a first case of international (UNO, UNESCO, IAEE) and European mobilisation for humanitarian, technical and financial assistance, relying also on geo-political backgrounds. The United Nations, USA and USSR helped Yugoslavia, with civilians and military resources. Romania was in this line, since its foreign politics started to move towards relaxing approaches. Some recent re-evaluations consider as forgotten the Tange s project (Lozanovska, 2012), although his fingerprint still defines the city. As the inhabitants participation was limited to the view the town models, it seems that not too much of pre-earthquake Skopje now survives. Under Ciborowskis s touch, Skopje is one of the few cities in the world rebuilt to meet earthquake disaster prevention criteria. The lesson is that the sustainable development cannot afford a modern urban architecture without earthquake safety. With the recommendation of the United Nations and the decisions of The Macedonia s Government and The City of Skopje, in 1965 was established the Institute of Earthquake Engineering and Engineering Seismology, IZIIS Skopje, within the University "St. Cyril and Methodius", Skopje. IZIIS was first Europe's institution of this kind, responsible to assist and supervise the post-earthquake reconstruction and development of the city. It was a premier example of how the role of earthquake prevention specialists may serve the society with their best knowledge. The opening of European and Balkan contacts and the creation of IZIIS were long-term gains. In 1964 it was held a UNESCO International Seminar on Earthquake Engineering, with participants from 12 countries, including Romania. We can say that the issues on debate have been a signal for a turning point in earthquake engineering as a strong partner to earth sciences, architecture and urban planning, i.e. towards interdisciplinary works (UNESCO, 1964). The meetings of prominent specialists lead to the creation of EAEE, the only Regional Association in the field for a long time. Macedonia, as part of Former Yugoslav Federation, is said to be the first European country which enforced the buildings seismic retrofit regulation in 1985 (Dumova-Jovanovska et al, 2012). In Romania, after March 1977, foreign specialist teams, including Yugoslavian / Macedonian experts, visited the damaged areas and openly exchanged views with Romanian partners. U. S. Aid and UNDP, Japan and China provided computers and seismic recording equipment. The opening of the Iron Curtain in Romania did not last under same freedom as after March 4, 1977 earthquake, but a COPISEE Conference was held in 1978, while two project of UNIDO and UNDP started in the 1980 s, Romanians attended UNESCO Seminars at IZIIS, in Bulgaria, Greece and Turkey. Romania used many standard designed structures, with the advantage of a good checking of calculations, testing in research institutes and public quality control. A quite uniform quality was achieved, except some lack of quality between 1975 and 1977, generated by the use of unskilled

7 workers. The March 4, 1977 was followed by a new Law no. 8/1978 on Safety of Constructions and it was created the State Inspectorate of Constructions. Bargaining with earthquake hazard in codes requirements, even after a great disaster, was at the will of officials (when increasing or decreasing of parameters was imposed), while some good decisions were often withdrawn. Thus, immediately after the March 4, 1977 earthquake, by Decree no. 66/1977, in the seismic zonation map the VII intensity zone was extended towards Western Oltenia, around the towns of Alexandria, Zimnicea and Craiova new zones of VIII and VII ½ intensity, respectively; the VII intensity zone of Timisoara was slightly modified. For Bucharest the VIII ½ intensity was introduced and for the Southern Dobrogea there was a zone of VIII intensity over a small area. But later on, in the zonation map of STAS 11100/1-77, some positive and negative modifications have been made such as: - the refinement and spread of the IX MSK intensity zone to Focsani area, the reduction of the VII intensity zone in western Oltenia and of the northern boundary of the VIII intensity zone; - the reduction by ½ degree of the intensity for Bucharest (VIII), by 1 degree of intensity for Alexandria and by ½ degree for Zimnicea, as well as introduction of the VII ½ intensity for Turnu Magurele and of new, local, VII intensity zones (Copsa Mica, Sighet, Radauti); the increase of the intensity by ½ degree for Iassy (VII ½ ); - splitting Dobrogea into VI intensity zones (east of Tulcea and north of Constanta) and VII intensity zones elsewhere; the adjustment of the intensity for north-western Transylvania. Recognizing the role of research, a loan from the World Bank for Romania was devoted to reconstruction and recovery of the building sector, but also to create a National Earthquake Protection Plan and a National Center of Earthquake Engineering at INCERC Bucharest. The project was postponed in 1983, funds were later on budgeted in local currency and imports deferred, thus the Center was only partly built and endowed (World Bank, 1978; 1983). After 1977, the Romanian regime used Vrancea earthquake as a pretext to trigger the systematization program, in fact the razing to the ground of urban and rural heritage. The need for repair or strengthening was replaced by the demolition of old low-rise houses in Bucharest and in some villages, although they were not at risk. On the contrary, today, the burden of high-rise vulnerable buildings in Bucharest is of some hundreds of high-rise apartment buildings that were not strengthened after Although research existed (Sandi, 1986) and regulations on existing building stock retrofitting were drafted at INCERC since the 1980 s, their application was postponed or limited. After political changes of 1989, INCERC introduced in the new earthquake resistant design codes P100/ 1991, 1992 (chapters 11 and 12, revised 1997), the obligation to evaluate and, if required, to rehabilitate the existing buildings. A Government Ordinance on Strengthening of Existing Buildings no. 20/1994 is in force. In Bucharest, some 120 buildings of first class risk were labeled with red placards, waiting for rehabilitation works. It was proven that the main problem is not the cost (high enough), but the slow rate of contracting and works. The 1963 and 1977 earthquake disasters opened the gates of knowledge in Europe and this is a very long term gain. The political will and public strategies play important roles, both in positive and negative issues. Some European Agreements and Programs can be used as a tool to enhance the speed of seismic risk reduction in the future (Georgescu, 2012). ACKNOWLEDGEMENTS The authors acknowledge the financial support of The European and Mediterranean Major Hazards Agreement (EUR-OPA) through the European Center for Buildings Rehabilitation (ECBR) for participation to the International Conference on Earthquake Engineering. 50 years from the Skopje catastrophic earthquake in July 1963, held in Skopje, Macedonia,

8 REFERENCES Ambraseys, N. (2010). Ambraseys IZIIS NNA / 1963 Skopje Earthquake Photos. Contribution to the 14 ECEE by Prof. Ambraseys and IZIIS. 14-th European Conference on Earthquake Engineering, Ohrid, Republic of Macedonia, Balan, St., Cristescu, V. and Cornea, I., (coordinators) (1982). The Romania Earthquake of 4 March 1977 (in Romanian). Editura Academiei, Bucharest. Berg, G.V., Bolt, B. A., Sozen, M. A., Rojahn, C. (1980). Earthquake in Romania, March 4, An Engineering Report. National Academy Press, Washington D.C., USA. Cismigiu, A., Titaru, E. (1964). The effects of Skopje earthquake on constructions (in Romanian, 2 parts). Revista constructiilor si materialelor de constructii, no , pp ; no. 5, 1964, pp Dumova-Jovanoska, E., Churilov, S., Necevska-Cvetanovska, G., Apostolska, R. (2012). Drafting of Macedonian NDPs for EN Design of structures for earthquake resistance - Part 3: Assessment and retrofitting of buildings. Proceedings 15-th WCEE - World Conference on Earthquake Engineering, Lisbon, Portugal, September 2012 Home, R. (2007). Reconstructing Skopje, Macedonia, after the 1963 earthquake: The Master Plan forty years on. Papers in Land Management No. 7, Anglia Ruskin University. Cambridge and Chelmsford. Ladinski, B. V. (1995). Post 1963 Skopje earthquake reconstruction: Long term effects. Chapter 6. www. desastres.usac.edu.gt/.../doc pdf Lewis, J. (2010). Some precedents for post-earthquake reconstruction: A bibliography of the work of Adolf Ciborowski. February Lozanovska, Mirjana (2012). Kenzo Tange's forgotten master plan for the reconstruction of Skopje, Fabrications, vol. 22, no. 2, pp Milutinovic, Z. (2001). Recovery of the City of Skopje following the 1963 devastating earthquake. RCDRS/DPRI, Kyoto University, Japan, April, 2001 Petrovski, J. T. (2003). Damaging Effects of July 26, 1963 Skopje Earthquake. Proc. SE-40 EEE UNESCO (1964): Proceedings of the International Seminar on Earthquake Engineering. Held under the auspices of the Federal Government of Yugoslavia and of UNESCO. Skopje, 29 September to 2 October Georgescu, E.S. (2002). Earthquake Engineering Development before and after the March 4, 1977, Vrancea, Romania Earthquake, Symposium 25 years of Research in Earth Physics, National Institute for Earth Physics, 25-27september 2002, Bucharest. Georgescu, E.S. (2012). Synergy and outreach within the European and Mediterranean Mediterranean Major Hazards Agreement (EUR-OPA). Case Study of ECBR Romania. Proceedings 15-th WCEE - World Conference on Earthquake Engineering, Lisbon, Portugal, September 2012 Georgescu, E.S., & Kuribayashi, E. (1992). Study on seismic losses distribution in Romania and Japan Proc. 10- th WCEE, Madrid, Spain, vol.10 pp , Balkema,Rotterdam. Georgescu, E. S. and Pomonis, A. (2007). The Romanian Earthquake of March 4, 1977: New Insights in Terms of Territorial, Economic and Social Impacts. International Symposium on Strong Vrancea Earthquakes and Risk Mitigation", October 4-6, 2007, International Conference Center of the Parliament of Romania, Bucharest. Symposium jointly organized by the UTCB Bucharest and the CRC 461 University of Karlsruhe, Germany. Georgescu, E. S. and Pomonis, A. (2008). The Romanian Earthquake of March 4, 1977 Revisited: New Insights into its Territorial, Economic and Social Impacts and their Bearing on the Preparedness for the Future. Proceed. 14th World Conference on Earthquake Engineering, October 12-17, 2008, Beijing, China. Georgescu, E. S. and Pomonis, A. (2010). Human casualties due to the Vrancea, Romania earthquakes of 1940 and 1977: learning from past to prepare for future events. Mizunami International Symposium on Earthquake Casualties and Health Consequences, November 2010, Mizunami, Gifu, JAPAN Sandi, H. (WG coordinator), (1986). EAEE Working Group on vulnerability and risk analysis for individual structures and for systems. Report to the 8-th ECEE. Proc. 8-thECEE. Lisbon, Portugal. World Bank (1978). Report No. P-2240-RO: Report and Recommendation of the President of the International Bank for Reconstruction and Development to the Executive Directors on a Proposed Loan to the Investment Bank with the Guarantee of the Socialist Republic of Romania for a Post Earthquake Construction Assistance Project, 17 May 1978 World Bank (1983). Report No. 4791, Project completion Report. Romania Post Earthquake Construction Assistance Project, Loan 1581-RO, November 18, 1983