(CASE STUDY MANJIL EARTH QAUCK)
Name: HIRA QAYYUM Student ID: 276923SUBMITTED TO: DR.IRFAN
TOC o “1-3” h z u Disaster: PAGEREF _Toc526200820 h 4Types of disasters: PAGEREF _Toc526200821 h 4Earth Quake: PAGEREF _Toc526200822 h 5Case Study PAGEREF _Toc526200823 h 5Regional Geology: PAGEREF _Toc526200824 h 8New faulting: PAGEREF _Toc526200825 h 9Background Seismicity: PAGEREF _Toc526200826 h 10Observed Damages: PAGEREF _Toc526200827 h 12Unreinforced Masonry Buildings: PAGEREF _Toc526200828 h 12Dams PAGEREF _Toc526200829 h 13Loshan Power Plant PAGEREF _Toc526200830 h 13Damage in Rasht PAGEREF _Toc526200831 h 16Soil Liquefaction: PAGEREF _Toc526200832 h 17Earthquake Hazards and Earthquake Environmental Effects PAGEREF _Toc526200833 h 19Primary effects PAGEREF _Toc526200834 h 20Subsidence PAGEREF _Toc526200835 h 20Surface Faulting PAGEREF _Toc526200836 h 20Secondary Effects PAGEREF _Toc526200837 h 20Liquefaction PAGEREF _Toc526200838 h 20Seismic Conditions PAGEREF _Toc526200839 h 21Pressure on Soil PAGEREF _Toc526200840 h 21Arrangement and Density of Soil Particles PAGEREF _Toc526200841 h 21Landslides PAGEREF _Toc526200842 h 21The Effect of Ground Shaking PAGEREF _Toc526200843 h 21Ground Displacement PAGEREF _Toc526200844 h 22Flooding PAGEREF _Toc526200845 h 22Tsunamis PAGEREF _Toc526200846 h 22Fire PAGEREF _Toc526200847 h 22Earthquake Recovery: PAGEREF _Toc526200848 h 23Emergency and temporary housing: PAGEREF _Toc526200849 h 23Housing reconstruction: PAGEREF _Toc526200850 h 24Reconstruction highlights: PAGEREF _Toc526200851 h 24Reconstruction challenges: PAGEREF _Toc526200852 h 25Proposed Guidelines PAGEREF _Toc526200853 h 26References: PAGEREF _Toc526200854 h 28
THE 1990 MANJIL, IRAN, EARTHQUAKE
Disaster:It is a severe disturbance of the functioning of society, which go beyond the ability of affected people to manage by using their own resources or an event, natural or manmade, progressive or sudden, is causing environmental, human or material losses.
Types of disasters:
Earth Quake:Earth quake is one of the major natural disasters. The shaking of earth’s surface in the result of sudden release of energy in earth’s lithosphere and creates seismic waves. Earthquakes can be vary in size, from those that are so feeble that they cannot be felt to those aggressive sufficient to throw people around and tear down whole cities. Earthquake can cause many other disasters like land sliding, volcanic activities, mine blast and many more.
Case StudyIran is one of the most seismically active country in the world because many major fault lines covered at least 90% of the country. The Iranian plateau is subject to most types of tectonic activity, including active folding, faulting and volcanic eruptions. It is well known for its long history of disastrous earthquake activity. Not only have these earthquakes killed thousands, but they have also led to waste of valuable natural resources. Since 1900, at least 126,000 fatalities have resulted from earthquakes in Iran.
The following table shows some history of earth quack that occurs in Iran:
Table – 1: History of Earthquakes in Iran
Date Province Mag. MMI Deaths Injuries Total damage
2018-08-25 Kermanshah 6.0 Mw VII 3 243 2017-12-20 Tehran 5.2 Mw VI 2 97 4.0 Mw aftershock: 1 dead, 75 injured
2017-11-12 Kermanshah 7.3 Mw VIII 630 8,435 2017-05-13 North Khorasan 5.6 Mw VII 3 370 2017-04-05 Khorasan-e Razavi 6.1 Mw VII 2 34 2017-01-06 Fars 5.0 Mw VI 4 5 2014-08-18 Ilam 6.2 Mw VIII 60-330 2013-11-28 Bushehr 5.6 Mw VII 7 45 2013-04-13 Sistan and Baluchestan 7.7M VII 35 117 2013-04-09 Bushehr 6.3Mw 37 850 2012-08-11 East Azerbaijan 6.4Mw VIII 306 3037 Doublet
2012-08-11 East Azerbaijan 6.3Mw Doublet
2011-06-15 Kerman 5.3Mw 2 2010-12-20 Kerman 6.5Mw IX 11 100 2010-08-27 Semnan 5.8 Mw VII 4 40 800 displaced
2008-09-10 Qeshm 5.9Mw 7 45 2006-03-31 Lorestan 6.1Mw VIII 63-70+ 1246-1418 2005-11-27 Qeshm 5.8Mw VII 13 100 2005-02-22 Kerman 6.4Mw VIII 612 1411 2004-05-28 M?zandar?n 6.3Mw VIII 35 278-400 $15.4 million
2003-12-22 Kerman 6.6Mw IX 26,271-43,200 22628-30000 45,000–75,600 displaced
2002-06-22 Qazvin 6.3Mw VIII 261 1500 1998-03-14 Kerman 6.6Mw VIII 5 50 1997-05-10 South Khorasan 7.3Mw X 1567 2300 1997-02-29 Ardabil 6.1Mw VIII 1100 2600 1990-06-20 Gilan 7.4Mw X 35000-50,000 60000-105000 1981-07-28 Kerman 7.1Mw IX 1,500 1,000 1981-06-11 Kerman 6.6Mw VIII+ 1400-3000 Many 1978-09-16 South Khorasan 7.4Mw IX 1400-3000 1972-04-10 Fars 6.7Mw IX 15000-25— 1710 1968-08-31 South Khorasan 7.4Mw X 5374 1968-09-01 South Khorasan 6.4Mw 15000 1965-02-10 East Azerbaijan 5.1Mw 900 1962-09-01 Qazvin 7.1Mw IX 20 2776 1960-04-24 Fars 6.0Mw 12225 1958-08-16 Hamadan 6.7Mw 420 1957-12-13 Kermanshah 7.1Mw 1130 1957-07-02 M?zandar?n 7.1Mw 1200 1953-02-12 Semnan 6.6Mw VIII 800-973 140 1947-08-05 South Khorasan 7.3Mw 500 1932-05-20 M?zandar?n 5.4Mw VIII 1070 1930-05-06 West Azerbaijan 7.1Mw IX 1360-3000 1929-05-01 Khorasan-e Razavi 7.2Mw IX 3257-3800 1121 1923-05-25 Khorasan-e Razavi 5.9Mw VII+ 2,200 More than 7 villages destroyed
1909-01-23 Lorestan 7.3Mw IX 6,000-8,000 1895-01-17 Khorasan-e Razavi 6.8Mw VIII 1,000-11,000 1893-11-17 Khorasan-e Razavi 6.6Mw X 18,000 1864-01-17 Kerman VIII Many 1853-05-05 Fars IX 13,000 1755-06-07 Isfahan 40,000 1727-11-18 East Azerbaijan VIII 77,000 1721-04-26 East Azerbaijan 7.7Ms VII-X 8,000-250,000 1679-06-04 Yerevan, Armenia 6.4Ms IX-X 7,600 Under Iranian rule at the time
1667-11-25 Shamakhi, Azerbaijan 6.9Ms X 80,000 Under Iranian rule at the time
On 21st June 1990, a destructive earth quack of Ms 7.7 occurred in the northern Iran near the town of Manjil. In a result, many towns were destructed, numerous villages and over 35,000 lives. Infrastructure either collapsed or was severely damaged. According to the local felt, the earth quack was a complex multiple shock.
In that earth quack, the overall seismic area extends over the Manjil basin, the Talesh Mountains to the north, and the Tarom Mountains to the south (Fig. 1).
FIG. 1: (Regional Geology)
The macro seismic region extends over the Manjil basin, the Talesh Mountains to the north and the Tarom Mountains to the south (Fig. 1). These Mountain ranges from parts of the western Alborz (also written as Elborz) Mountain System of northern Iran (NIOC, 1978), a precise method that stretches in a broad east-west direction along the southern shores of the Caspian Sea. The maximum peak, Damavand (5670 m), which is located in the north of Tehran. The sudden northern slopes of the Alborz Mountains facing the Caspian Sea are covered by dense forests. The southern slopes, however, are commonly barren. According to Stocklin (1974), the South Caspian Depression is characterize by an oceanic crust, might be a remnant of Paleo-Tethys, which constituted the most considerable opening between the Eurasia and Gondwana in late Triassic and which vanished by late Jurassic. Developed as part of the Alpine-Himalayan orogeny in Late Cretaceous- Tertiary time, the Alborz Mountains are made up of analogous mountain depression of the up-and-coming Alborz range” under a parched situation (NIOC, 1978). Sefidrud dam (also referred to as Manjil dam) is built near 2km northwest of Manjil (town) at the opening of the Sefidrud Valley. Sefidrud (white river) is shaped by the union of two rivers, Qizil Uzun and Shahrud, which flow from the reverse sides of the basin to meet upstream from the Sefidrud Dam. Sefidrud Valley traverses the general trend of the Talesh Mountains northward towards Rudbar and provides the only access way from central Iran to the Caspian Sea in western Alborz. The Paleozoic-Mesozoic rocks of the Manjil-Rudbar part of the Talesh Mountains are strongly faulted. These rocks form the core of a west-plunging anticline boost within the Euocene Karaj Formation (Stocklin and Eftekhar-nezhad, 1969). The Paleozoic limestone of Manjil here up thrust northward on Jurassic rocks. Likewise, the Paleozoic-Eocene contact is faulted and somewhat overturned. The Eocene Karaj Formation, which is broadly bare over the southwest flank of the Talesh Mountains, dips steeply under the Neogene fill of the Manjil basin. According to Stocklin and Eftekhar-nezhad (1969), the Neo-gene beds show mild folding but small or no faulting. However, the plane of contact with the Karaj Formation is faulted and a little reversed.
New faulting:Moinfar and Naderzadeh (1990) exposed a new fault trace of about 80km length, which they recognized as the major rupture linked with the 20th June 1990 event. The reported fault (almost parallel to the local structural trends) and follows in a part of the northeastern border of Manjil basin. In fig.2 more detail and map of the reported fault trace (dashed line) as well as the site of the main shock’s epicenter. The uncertain fault segment near Abbar is shown by dashed line. Moinfar and Naderzadeh reported a steady right lateral sense of motion. The most measured horizontal and vertical offsets are 20 and 50cm respectively. The reported vertical offset of almost 2.5m at a point near Pakdeh village is interpreted to have been caused by road settlement. Berberian et al. (1991) vary with the field analysis of rupture by Moinfar and Naderzadeh and state that the main fault rupture linked with the Manjil earthquake is located above 2Km elevation some kilometers north of the trace recognized. Berberian et al. (1991), explains the rupture to consist of three en-echelon fault segments of 80Km least total length showing “left-lateral oblique high-angle reverse” movement. Allocate a similar, 115 ° to 120 ° strike to the fault trace.
FIG. 2: (Epicentral map of Manjil earth quack)
The fault trace (shown by a thick dashed line) and an experiential splay (revealed by a thin dashed line) are reported by Moinfar and Naderzadeh(1990).The locations of the strong-motion stations along with the larger of the two horizontal peak Accelerations are also shown.
Background Seismicity:The Alborz Mountains recline along the seismically vigorous Alpine-Himalayan belt, a number of strong earthquakes have caused serious damage and loss of lives in these mountains. They have been centered in the eastern and central Alborz. Ambraseys and Melville (1982) make indication to several strong earthquakes centering in the Taliqan (Taleghan) Mountains, over 100Km to the east of Manjil (centering roughly near 36.2°N, 50.8°E). The predictable location and scale for these earthquakes are given in Table-1. Figure 3 shows the division of the instrumentally positioned earthquake epicenters of this century within the 2 ° × 3 ° oblong bound by 36″N and 38°N latitudes and 48°E and 510E longitudes, prior to the main shock. According to Moinfar and Naderzadeh (1990), Manjil suffered minor damage on 17th June, 1948 from a moderate earthquake of M5.5.
Table – 2: Historical Strong Earthquakes in Taliqan Mountain
FIG. 3: (Division of the instrumentally positioned epicenters of earthquakes of this century past to the main shock)
Observed Damages:The Manjil earthquake caused severe damage to multiple types of structures. Besides non-engineered buildings, which were damaged substantially, there were also a number of major engineered facilities in the area. These include a large concrete dam, a fossil-fueled power plant, and reinforced concrete water distribution tanks, some of which experienced damage. A brief summary of the performance of some structures is presented here. Investigation reports have been published by Moinfar and Naderzadeh (1990), Mehrain (1990), and Yegian and Ghahraman (1990).
Unreinforced Masonry Buildings:Unreinforced masonry and stone buildings were mainly responsible for the human casualty in this earthquake. Collapse of such buildings occurred in hundreds of villages and several towns. Fig.4 shows the collapse of an unreinforced masonry wall in Manjil. The town located less than 3Km from the fault trace as reported by Moinfar and Naderzadeh (1990) was the center of the damage. Fig.5 shows the main street in Manjil collapse of many buildings is evident.
FIG. 4: (Collapse of an unreinforced masonry wall in Manjil, Many unreinforced masonry buildings were damaged beyond repair in the epicentral area)
FIG.5: (The main street in Manjil, evidence of severe damage in this epicentral town)
DamsSefidrud dam is a major concrete buttress dam, 425m long and 106m high, constructed about 30 years ago. The dam which was located near the town of Manjil, endured the earthquake with minor damages. However, some horizontal cracks in the top portion of the buttresses were observed. A portion of the concrete parapet on the crest was also damaged. Based on the recorded accelerations at other sites, it is estimated that the peak horizontal ground acceleration at the dam site may have reached 0.50 g. Tareek dam is a small diversion dam near the city of Rasht, about 60Km north of Manjil.
Loshan Power PlantLoshan power plant is one of the major industrial facilities in the area. It is a modern fossil-fueled plant, consisting of two units of steam turbine-generators, 120MW each and two units of gas turbine-generators, 52MW each. The plant is located in Loshan which is about 12Km from the fault trace identified by Moinfar and Naderzadeh (1990) and about 18Km from the fault trace identified by Berberian et al. (1991). During the earthquake, the Loshan power plant experienced substantial damage and consequently went out of operation for a long time. The main turbine building of the plant consists of a reinforced concrete frame with masonry infill. The earthquake caused the collapse of the infill near the roof level as well as the top of the reinforced concrete columns (Figs. 6 & 7). The infill and the reinforced concrete elements collapsed into the adjacent yard. As a result, the circuit breakers, conduits and other equipment in the switchyard were severely damaged. Fig. 8 shows the collapse of the masonry infill on a main bus duct that was running out of the turbine building. This is a clear example of the equipment damage caused by impact of heavy debris. Another type of damage in the Loshan power plant was settlement of the foundation of one of the turbine-generators. Fig. 9 shows a corner of the foundation and the reinforced concrete pedestal, which established about 2 inches. This settlement may be due to an arrangement of soft soil and a high overturning moment. Consequently, the operating deck at the turbine-generator level also settled. A misalignment of the turbine-generator was also found after the earthquake. The Loshan plant experienced other types of damages including damage to the masonry infill panels in the administration building. Steel fuel storage tanks were located on the ground. Fortunately, at the time of the earthquake they were almost empty and thus did not experience any damage. The median values of the horizontal and vertical peak ground accelerations at Loshan are estimated to be 0.37 and 0.28g respectively. These are based on the case (2) attenuation model with a distance of 12Km from the fault trace. The estimated peak accelerations based on the case (3) attenuation model with a distance of 18Km from the fault identified by Berberian et al. (1991) are 0.31 and 0.24g for the horizontal and vertical components respectively. However, local soil condition at the plant may have amplified ground motion further.
FIG.6: (Main turbine building of the Loshan power plant, the top infill collapsed during the earthquake)
FIG.7: (Main turbine building of the Loshan power plant. Collapse of the top portion of reinforced concrete columns along with the infill.
FIG. 8: (Loshan power plant; the masonry infill collapsed onto the bus duct that was running out of the main turbine building, the impact of heavy debris resulted in equipment damage)
FIG. 9: (Settlement of the pedestal of one of the turbine-generators in Loshan power plant. A corner of the foundation and the heavy reinforced concrete column shown on right settled about 2 inches)
Damage in RashtThe city of Rasht is the provincial capital of Guilan and a major city located near the Caspian Sea coast, some 40Km north-east of the NEIC epicenter and about 60Km north of Manjil. Some of the observed damages in Rasht are summarized below. The city hall is a historical structure reportedly constructed about 60 years ago. It is a two story unreinforced masonry (URM) building. During the earth-quake, the dome of the city hall collapsed, as shown in Fig.10 and 11. However, the arch-type ceiling of the first story experienced no significant damage. A second historical URM building is the city administration building, constructed about the same time as the main city hall. Portions of the exterior walls of this building were also damaged. Several mid-rise buildings collapsed or damage severely in Rasht. These includes the collapse of a five-story reinforced concrete frame apartment building with a questionable material quality (Fig. 12); the collapse of six- and eight-story welded connection steel frame buildings etc. Examples of the buildings with damage to their infill including a four-story reinforced concrete frame office building (the frame itself experienced only minor damage), two eight-story apartment buildings consisting of steel frames and hollow block infills (the steel frames were undamaged), a six-story steel frame with masonry infills of the Guilan Medical School, a seven-story steel frame, etc. The main water tank in Rasht collapsed during the earthquake and the city did not have drinking water for a few hours. This elevated water tank had enforced concrete shaft and 1500m3 capacity. The collapsed water tank is shown in Fig. 13. There are two other elevated water tanks, similar but larger than the collapsed tank. These new tanks have a capacity of 2500 m3; they are about 50 m tall and are supported by piles. Fortunately, these tanks were empty and not yet in operation at the time of the earthquake. Vahdani and Noori-Samie (1991) modeled the tanks by finite elements and estimated the fundamental period of these new tanks at 1.5 sec. Horizontal cracks were developed near the base of the cylindrical shell.
Soil Liquefaction:Widespread damage caused by liquefaction was observed in the town of Astaneh-Ashrafieh, about 30Km east of Rasht and about 70Km north-east of the macro seismic center. Soil liquefaction caused sand boils, ground settlement and tilting of buildings in the town. Crawl spaces under houses were filled with sand. Several water wells were also observed to be filled with sand. Ground settlement and tilting of a building and a wall Evidence of liquefaction in Loshan was also reported by Moinfar and Naderzadeh (1990).
FIG. 10: (Dome of the Rasht city hall, a historical building collapsed during the earthquake)
FIG. 11: (Collapsed dome inside the Rasht city hall)
FIG. 12: (Collapse of a five story reinforced concrete frame building in Rasht)
Fig. 13: (Collapse of the elevated water tank in Rasht)
Earthquake Hazards and Earthquake Environmental EffectsSurface faulting, subsidence, tectonic uplift, and liquefaction of soil and landslides are some examples of such effects. These effects can be directly connected to the earthquake or can be incited by the shaking of ground. EEEs can be observed in areas near the epicenter of the earthquake or areas far away from the epicenter. EEEs affect manmade structures in addition to leaving its impressions on the environment. During large earthquakes EEEs act as a major source of hazard. EEEs are increasingly being used as equipment for measuring the intensity of an earthquake. Effects of earthquakes can be categorized as primary and secondary. Primary effects occur as a direct result of the earthquake, whereas secondary effects are incited or induced by the primary effects. Primary effects are exhibited at earth’s surface due to the interferences at the tectonic source capable of generating an earthquake. They can consist of surface faulting or uplift, subsidence or any other ground surface activity due to earthquake generated tectonic deformation. Secondary effects are incited by the shaking of ground; examples are liquefaction, Tsunami, landslide, cracking of ground, displaced rocks, destruction of trees etc.
Primary effectsPrimary effects take place as a direct consequence of the earthquake. The happening of the primary effects also depend on the size of the earthquake and the stress environment. Two earthquakes which dissipate same amount of energy but have different stress environments and focal depths are able to produce dissimilar environmental effects, so the local intensity values of both the earthquakes can also vary. This variance of intensities becomes more prominent in case of earthquakes having shallow focal depths (less than 4 km) and low magnitudes, e.g. areas near volcanic hotspots. Due to this reason some macro seismic intensity scales such as ESI-2007, consider a lower intensity value (VII) for earthquakes having shallow depths and a higher intensity value (VIII or more) for earthquakes in volcanic areas or having higher focal depths.
SubsidenceThe movement of the earth surface from a higher to a lower position with respect to a particular datum such as the mean sea level is known as subsidence of earth’s crust. The opposite of subsidence is uplift, both subsidence and uplift are a matter of research for geologists, engineers and surveyors. Subsidence is measured in units of length. Observations from some earthquakes suggest that soil subsidence can also be triggered by liquefaction of sand which can create serious problems.
Surface FaultingSurface rupture is a displacement which reaches the earth surface due to the motion of a fault inside the earth, during an earthquake. This phenomenon commonly occurs in shallow earthquakes (depth below 20Km). The effects of earthquake on the environment like surface faulting and ground cracks can be utilized to specify the epicentral area of the earthquake, intensity of damage and assessment by comparison with historical data.
The effects which occur in the natural environment as a result of the primary effects are known as Secondary Effects.
LiquefactionLiquefaction of soil is process in which saturated, partially saturated and cohesion-less soils loses strength and stiffness in response to ground shaking due to earthquake or other quick loading, resulting in a fluid like behavior of the soil. In this process the pore water pressure in the interior of soil increases and hence effective stress caused by dynamic loading decreases. Effective stress becomes negligible when pore pressure equals total stress causing the suspending of soil particles in water, which leads to liquefaction. Some factors which effect liquefaction of soil are described as under;
Seismic ConditionsThe distance of a particular area from the epicenter of the earthquake affects the intensity of ground motions and also the cyclic loading transferred to the soil. The risk of liquefaction was found to increase with the increase of cyclic loading.
Pressure on SoilSoils having high overlying earth pressure such as areas with buildings, roads or any other loading were found to be less prone to liquefaction then open areas such as crop fields or beaches with shallow alluvial deposits.
Arrangement and Density of Soil ParticlesA porous layer has lesser liquefaction resistance than closely packed soil. Liquefaction resisting strength is more for denser soils.
LandslidesA landslip is a mass movement of rocks, debris or top layer of soil down a slope which is aided by the action of gravity. Landslides can be triggered by an earthquake or other causes like volcanic eruption, changes in ground water table disturbance caused by human activities. While collecting information related to the impact of a landslide on the environment, it is also necessary to find out the exact location of occurrence of the landslide, magnitude of the earthquake and the possible types of errors involved an earthquake can trigger a single a single landslide or many landslides. Earthquake is a major triggering factor in the generation of landslides, in fact the destruction caused by landslides and other secondary effects sometimes exceeds the damage caused by ground shaking. Newmark’s dynamic displacement model can be used for assessing slope stability when subjected to an earthquake due to these different models and methods have been developed for landslide risk assessment.
The Effect of Ground ShakingThe effect of ground shaking is the first main earthquake hazard (danger). Buildings can be damaged by the shaking itself or by the ground beneath them settling to a different level than it was before the earthquake. Buildings can even sink into the ground if soil liquefaction occurs. Liquefaction is the mixing of sand or soil and groundwater during the shaking of a moderate or strong earthquake. When the water and soil are mixed, the ground becomes very soft and acts similar to quicksand. If liquefaction occurs under a building, it may start to lean, tip over to several feet. The ground firms up again after the earthquake has past and the water has settled back down to its usual place deeper in the ground. Liquefaction is a hazard in areas that have groundwater near the surface and sandy soil. Buildings can also be damaged by strong surface waves making the ground heave and lurch. Any buildings in the path of these surface waves can lean over from all the movement. The ground shaking may also cause landslides and avalanches on steeper hills or mountains, all of which can damage buildings and hurt people.
Ground DisplacementThe second main earthquake hazard is ground displacement (ground movement) along a fault. If a structure is built across a fault, the ground displacement during an earthquake could seriously damage or rip apart that structure.
FloodingFlooding is the third main hazard. An earthquake can rupture dams or levees along a river. The water from the river or the reservoir would then flood the area, damaging buildings and maybe sweeping away or drowning people.
A tsunami is what most people call a tidal wave, but it has nothing to do with the tides on the ocean. It is a huge wave caused by an earthquake under the ocean. Tsunamis can be tens of feet high when they hit the shore and can do huge damage to the coastline. Seiches are like small tsunamis. They occur on lakes that are shaken by the earthquake and are usually only a few feet high.
FireThe fourth main earthquake hazard is fire. These fires can be started by broken gas lines and power lines, or tipped over wood or coal stoves. They can be a serious problem, especially if the water lines that feed the fire hydrants are broken. Most of the hazards to people come from man-made structures themselves and the shaking they receive from the earthquake. The real dangers to people are being crushed in a collapsing building, drowning in a flood caused by a broken dam or levee, getting buried under a landslide, or being burned in a fire. Earthquakes are a natural phenomenon which causes destruction. The effects of earthquake on the natural environment are known as EEE. EEE can be further classified as primary effects and secondary effects. Primary effects are a direct result of the earthquake and secondary effects are caused due to the primary effects.
Earthquake Recovery:Considering the Country’s seismicity and the impacts and consequences of earthquakes, recovery experiences based on two events in Iran to develop some guidelines toward risk reduction. The main topic is housing reconstruction and recovery in emergency, temporary and permanent phases in post-quake. Earthquake recovery with emphasize on housing reconstruction in one experience in Iran Manjil Earthquake (1990). This experience can be helpful in improving earthquake preparedness and response plans at national and local levels. Shelter and housing are among the immediate needs of the residents in earthquake stricken areas. Shelter is a critical determinant for survival in the initial stages of a disaster. Beyond survival, shelter is necessary to provide security, personal safety and protection from the climate and to promote resistance to ill health and disease. It is also important for human dignity, to sustain family and community life and to enable affected populations to recover from the impact of disaster. The Manjil Earthquake affected Gilan and Zanjan Provinces in northern parts of Iran. This earthquake destroyed three cities (Rudbar, Manjil and Loshan) and about 700 villages. More than 15000 people were killed and more than 30000 people were injured. Also more than 500000 people became homeless. Among affected people the 6.3 per cent were in urban areas and the others were in rural areas. About two hundred thousands of residential and non-residential buildings were damaged. This earthquake has affected relatively large areas in the region and even was felt in Tehran (225 km southeast of epicenter) which caused fear and panic.
Emergency and temporary housing:Public buildings such as schools had damaged highly so these places could not be used as emergency shelters. In some affected cities the residents were settled in schools but after a few months they had to leave these buildings due to the beginning of the academic year. In most damaged cities and villages the affected people could not be settled in public spaces and therefore they had to live next to their demolished houses in unsuitable conditions for a while. Due to population dispersion in affected areas, provision of the basic needs and security was very difficult for responsible authorities. Later on, tents were distributed among households as emergency shelter but some households received more than one tent and some others did not receive anything. In some cases some households had to live in one tent together. Due to the spread of the affected areas and dispersion of damaged villages, it was very difficult to set up emergency camps and even in cities where such camps were set up; people were reluctant to move into them. There were not enough emergency baths and toilets in emergency camps that cause problems for the residents. For temporary settlement different methods were considered as cash donation and distribution of construction materials, contribution in preparing small temporary housing through local sources and provision of prefabricated houses. Although the authorities intended to prepare the temporary houses during summer and before the beginning of cold season but in many areas especially rural areas, people had to live in tents for several months.
Housing reconstruction:To accelerate the reconstruction pace, different provinces in the country formed auxiliary taskforces and each taskforce was appointed to complete the reconstruction work in its territory by three years. Therefore, many provinces in the country got involved in reconstruction of the affected areas and many technical and administrative sources could be used. (Taleb 1993)The auxiliary taskforces were responsible to provide construction materials. They evaluated the requirements and prepared the materials. It was decided that the construction materials be delivered to households. But due to some reasons such as inability of the responsible institutes to prepare the materials, inability of some areas in providing proper materials and delays in materials delivery in some areas, residents of the affected areas had to provide materials by themselves from inside and outside of affected areas. For example, some people cut some forest trees and constructed their houses in a traditional style. This indicates that the same vulnerable buildings were constructed. On the other hand, the prices of construction materials increased after the earthquake, thus the survivors encountered further challenges in reconstructing their damaged houses (Daneshjou 1993).
Reconstruction highlights:Since constructing resistant houses was the focus in this reconstruction experience, the model plans were used. These model plans had the same design and materials regardless of the social and economic status of residents. Considering the Iran’s earthquake standards at that time, the structure’s resistance was a function of materials and construction style. Consequently similar designs were built that were far from desires of local residents. In some cases in order to adapt the conditions of new built houses with social status, residents added some spaces inside their houses after the reconstruction; see Fig. 14.In rural areas assigning the reconstruction work to rural residents and confining the outside help to financial and materials’ contribution and technical supervision, were important elements in accelerating the reconstruction work. In urban areas people expected more contributions from government due to the authorities promises to help them in reconstruction. This means that even if they had the financial power to reconstruct their own houses, they preferred to use the public sources instead and consequently did not use their power and abilities. If the auxiliary taskforces could attract people participation in reconstruction, more success would be achieved. There were military organizations in taskforces that work centrally without considering community participation. Such organizations have an up-down structure that has no congruity with community participation. During reconstruction phase, these organizations could not decide on how to assign the work to people. (Taleb 1993)
FIG. 14: (Examples of adding spaces to houses by residents)
Reconstruction challenges:There were different challenges in housing reconstruction in this experience such as:In reconstruction work, the non-native labors worked and consequently not only the reconstruction expenses increased but also the local residents did not get job as well. Difficulty in securing the technical staffs and lack of familiarity and experience of other staffs such as informed and skillful builders led to constructing the same vulnerable houses in some affected areas. Some auxiliary task forces imported some types of designs and construction materials that had no integrity with the affected society. This was due to unfamiliarity with the living conditions in affected areas and consequently some problems appeared as well. Although some task forces used model plans for construction but some others did not used them. In such cases, people had to start construction based on their own potentials, needs and knowledge that mostly were vulnerable to potential earthquakes. Since there were many differences in social and geographical characteristics of the affected areas, the unique reconstruction method caused problems. Lack of technical knowledge about proper construction methods among authorities in affected areas, led to high vulnerability of buildings and this indicates the importance of awareness on technical knowledge for different groups. Some damaged residential units in cities located on landslide or rock fall prone areas. In such areas, the landslide risk, or rock fall would be predictable and if people were aware about the potential risks, they would never construct their houses in such areas and consequently the damages would reduce as well.
At the time of this event, there has not been any earthquake or hazard insurance in Iran. The only existed insurance was fire insurance in which the natural hazards damages had been considered as well. Only limited numbers of private buildings had insurance against fires and natural hazards. Besides, damage compensation for such buildings had many challenges due to unfamiliarity with damage compensation mechanisms by insurers. Lack of comprehensive insurance at time of the event let to imposing much pressure to residents and government. Due to high levels of damage and the government limitations in gratuitous aids, some policy makers considered the importance of earthquake insurance after the event but not much was done to develop earthquake insurance in the country.
Proposed GuidelinesBy considering the case study experience the following guidelines are proposed:
Developing regional to local reconstruction plans in pre event, Proper reconstruction plans are based on local conditions and sources to achieve optimum results. This indicates that reconstruction plans need to be prepared in pre event. Planning for any reconstruction or recovery plan in after math of disaster due to disturbances and lack of authorities presence could not lead to a comprehensive and appropriate one. For any seismic prone country, it is necessary to include regional and local reconstruction plans in the risk reduction plan. Regional reconstruction plans necessitate regional vulnerability assessment plans and studies on appropriate construction methods in different areas. Integrating socio-cultural aspects in housing reconstruction along with technical aspects, although resistant construction is effective in reducing vulnerability during reconstruction, but neglecting the culture of affected areas could end in vulnerable construction. Adding spaces inside reconstructed houses by residents is an example of disregarding social aspects in reconstruction. Besides, the resistant construction should be understandable by residents and local constructors. This indicates that model plans could not be appropriate for reconstruction since social and cultural characteristics of affected households do not taken into consideration.
Promoting public awareness about proper construction, the public need to be aware about safe construction methods with the available materials and sources. The public can play important roles in safety of their houses. To achieve this, people should always keep informed through different means with considering their social and economic status.
Documenting housing reconstruction experiences and challenges, making documentations on previous experiences and challenges in housing reconstruction. Documentation can improve the level of preparedness among reconstruction authorities and administrators to confront the unpredictable situation in post event phase.
Conducting local sources toward individual housing reconstruction, local sources such as labors, materials and even financial sources are very important in individual reconstruction projects. For this purposes it is important to recognize these sources and adopt some incentive policies to absorb them in reconstruction projects. As in case studies observed people expected the government to start reconstruction even in cases that they owned their own housing. This is because the reconstruction process was based on outside sources. To absorb local sources it is important to recognize local capacities and potentials. Urban comprehensive plans and urban development plans can facilitate the recognition of local capacities. Another important point in absorbing local sources is considering the low-income groups in housing reconstruction projects. Since these groups damage more during disasters, their housing needs should be taken in to account in reconstruction plan. Otherwise, the same vulnerable houses are built in vulnerable locations.
Improving public participation in reconstruction through community based organizations, public participation is very important in promoting housing reconstruction programs since could conduct local sources toward housing reconstruction. Community based organizations especially in urban areas can work as a medium between residents and authorities. Such organizations can work on welfare activities in neighborhoods units in pre event situation and can prepare residents to confront with probable disasters. These organizations can hold rehearsals for residents on how to evacuate their houses, how to rescue their family members and neighbors or how to handle some secondary disasters such as firefighting. Besides, these organizations can educate residents on the importance of resistant housing and avoiding from housing construction in vulnerable locations.