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Nicholas Novakowski, Recep Efe Fatih University, Department of Geography Büyükçekmece-İstanbul, Turkey 34900 ABSTRACT The catastrophic August 17th, 1999, earthquake in the Gölcük-İzmit area provides a living laboratory for investigating the implications of settlement patterns and land use in regions prone to seismic activity. A preliminary case study approach to lessons learned from the August 17th earthquake is provided. A proposed range of planning strategies for earthquake-prone areas is described, explained and prescribed. The land use planning role in guiding settlement patterns, in conjunction with building codes, is argued to represent one of the most important and enduring contributions concerning the mitigation of the human consequences of earthquakes. INTRODUCTION The Gölcük-İzmit area lies at the eastern edge of the Sea of Marmara and straddles the North Anatolian fault running east-west in northwestern Turkey. The Gölcük-İzmit area lies within the Marmara Region of Turkey and is part of the nation's industrial heartland. Of the seven regions of Turkey, the Marmara Region has the highest population density and the highest levels of GDP (Oxford Business Group, 1998). The local economies are dominated by primary (e.g., agricultural) and secondary (e.g., industrial) activities. On August 17, 1999, a catastrophic earthquake occurred in the Gölcük-İzmit area. The primary earthquake measured 7.4 on the Richter scale. The United States Geological Survey or USGS (1999) reports that at least 17,118 people were killed and that over 50,000 were injured by the earthquake. Thousands of people remain missing and unaccounted for, and over 600,000 people were left homeless. Extensive human and property impacts related to the earthquake were experienced throughout Kocaeli, Sakarya and Istanbul provinces. Damage is estimated by government sources to be approximately $12 billion US (Gorvett, 1999). The earthquake involved a right-lateral, strike-slip motion of the nearly vertical North Anatolian fault between Karamürsel and Gölyaka. The duration of the strong ground-shaking was 37 seconds (USGS, 1999). Site visits to the Gölcük-İzmit area conducted in September and October, 1999, demonstrated an extensive range of earthquake-related devastation: fault rupture, tectonic displacement, plus evidence of soil liquefaction, landslides, flooding and fire. EARTHQUAKES AND LAND USE PLANNING "An earthquake is the vibration of the Earth produced by the rapid release of energy…the energy released radiates in all directions from its source, the focus, in the form of waves" (Tarbuck and Lutgens, 1997: 155). Earthquakes are associated with a variety of primary and secondary effects and impacts. Primary effects include ground-shaking, fault rupture and tectonic deformation. Secondary effects include soil liquefaction; rock, mud or land slides; submarine, snow or ice avalanches; fire; and flooding due to tsunamis, seiches, and alterations to the water table or to stream and river courses (Smith, 1996). These primary and secondary effects can induce a range of impacts: human destabilization, injury or death; damage to private and public property (e.g., homes, businesses, infrastructure); and the potential destruction of social or economic cohesion within an affected community. The extensive damage associated with the Gölcük-İzmit earthquake demonstrates the need for comprehensive land use planning in areas facing seismic risk. Land use planning is "the process of protecting and improving the living, production and recreation environments in a city through the proper use and development of land" (Leung, 1989: 1). The primary concerns of land use planning include public welfare and security, circulation, environmental protection, beauty, comprehensiveness, conservation of resources, efficiency and equity. The potential contribution of a variety of land use strategies pertaining to both the primary and secondary effects of earthquakes was considered during the site visits. Ground-shaking : The main hazard created by seismic activity is ground-shaking, which can be explained on the basis of four types of elastic waves: the primary or P wave, the secondary or S wave, and the L or long waves - either Love or Raleigh waves (Abbott, 1996). "The severity of ground-shaking at any point depends on a complex combination of the magnitude of the earthquake, the distance from the rupture and the local geological conditions, which may either amplify or reduce the earthquake waves" (Smith, 1996: 126). With strong ground-shaking, the earth moves, buildings shift or collapse, plaster cracks, chimneys and architectural ornamentation fail, and underground pipes can be bent or sheared. Perhaps the most important tool that planners have for anticipating the potential impacts of ground-shaking is zoning, the planning instrument that deals with the land uses and the physical form of development on individual parcels of land (both private and public). In other words, zoning can be used to designate the sorts of activities and the types of buildings permitted on specific land parcels. An earthquake-sensitive planning process begins with a comprehensive inventory of seismic hazard that identifies the land parcels along fault lines plus those areas subject to the danger of soil liquefaction, landslides, flooding, fire and any other secondary effects that make ground-shaking even more destructive. Considerations that are central to zoning in earthquake-prone areas include the following: · Prohibit high-density development along active fault lines, in fault or fracture zones, and in potential liquefaction areas. · Permit the following land uses in fault zones: agricultural land uses (e.g., crops, livestock, orchards, etc.), recreational land uses (e.g., parkland, cycling paths, golf courses) and light industrial uses with low staff levels or those using robotics (e.g., advanced technology firms). In some circumstances, low-density residential may be acceptable, but it must be recognized that there is always a risk trade-off that must be countered with earthquake-sensitive architecture. · Zone high-priority infrastructure like hospitals, airports, subways, power stations, telecommunication spines, and bridges in areas of lower potential seismic activity. · In site planning, encourage a variety of escape routes from individual sites at risk. Superior access for emergency vehicles is also a consideration. · Zone the production locations and storage of hazardous and toxic materials at safer sites. · Identify parcels that were once landfill sites or were reclaimed from the sea and minimize development potential on them. And, · Use set-backs to minimize pounding between adjacent buildings. Infrastructure investment is another planning tool that can be effectively used to guide settlement patterns away from areas of high seismic risk. Investment in highways, roads, bridges, public transportation, sewers and water supply represent tangible expressions of how an urban government desires future development to be expressed across the urban landscape. Government ownership of land in the urbanized areas of Turkey is extensive and can conceivably be used to effectively phase long-term infrastructure investment. Another important implementing tool of an urban plan is the building code. The building code establishes structural and utility standards for the construction of homes, and commercial, industrial and institutional facilities (ASCE, 1986). Building codes in earthquake-prone areas need to address the functionality of buildings over time, rather than just at one point before occupation (Eisner et al., 1993). More specifically, building codes can be used to specify construction details that are particularly relevant to earthquake-based hazard. As Zebrowski (1997: 55) observes, "the death toll from an earthquake has more to do with the type of building construction than with the intensity of the earthquake. Earthquakes seldom kill people; for the most part, it is our buildings that kill people." The following elements of construction detail represent rudimentary content for local building codes: · The five primary considerations for building codes in areas of seismic risk include building height, consolidation of weight on the lower floors, the shape of buildings, the type of building materials, and the degree of attachment of the building to its foundation (Abbott, 1996). · Height and density restrictions are essential unless earthquake-resistant technology is used (e.g., steel frames, shear walls). Building weight must be concentrated in the lower stories. · Building shapes are an important consideration. While cantilevering and complex building massing should be avoided, stepped building profiles appear to work well (Smith, 1996). · Building materials are critical and need to be both high-quality and fire-resistant. "Strong, flexible and ductile materials are preferred to those which are weak, stiff and brittle" (Smith, 1996: 139). Zebrowski (1997) argues for the use of prestressed concrete columns or walls in areas subject to seismic stress when better but more expensive alternatives are not feasible. Since property developers can save money by compromising the quality of the concrete used in construction, this possibility needs to be carefully monitored in the application of the building code across time (rather than in a single inspection). · The type and reinforcement of building frames can also be critical (e.g., wood frames for buildings up to four stories, the prohibition of brick in a load-bearing function, prevention of soft stories on the ground level, the anchoring of frames to the foundation). The use of building reinforcements like trussing, shear walls, braced frames and moment-resisting frames needs to be stressed (Abbott, 1996). In the Gölcük-İzmit area, many buildings where brick was used in a load-bearing function had pancaked. And, · Design restrictions also play a role in the safety of both the building's residents and people in the building's proximity during an earthquake (e.g., all architectural detail or ornamentation like pediments or statuary should be reinforced, and the use of large glass exterior walls should be minimized). "Architectural style can contribute to disaster if features like chimneys, parapets, balconies and decorative stonework are inadequately secured" (Smith, 1996: 141). Despite the wide array of concerns that can be addressed through the building code, it is also important to recognize that the code can be circumvented by either corruption or sanctioned political pressure. There are a number of mechanisms that optimize the implementation of the building code. First, close observation of the inspection process by local politicians is mandatory. Second, federal watch-dog organizations with the power to enforce local codes can do spot checks to monitor code implementation as well as the performance of local councils. Third, there are also economic mechanisms that can be employed. Building inspectors in earthquake-prone areas should be extremely well-trained and rewarded for their jobs. As well, property developers with good construction records can be rewarded with density bonuses for future projects. The building code priorities identified above need to be addressed before a building can be considered habitable. For buildings that are already built, already inhabited, and are suspect, the urban planner still has a few instruments that can operate retroactively. Local governments can act through land acquisition or land swaps in order to deal with developed areas that are at particular risk. In an arena of last resort, a local government can use its power of eminent domain (i.e., expropriation). Expropriation involves a municipality obtaining privately-owned land for community purposes and paying for it at market value as assessed by an independent land appraiser (Hodge, 1991). In other words, if certain properties and the structures on them are at particular risk, the municipality can intervene in the private property market and purchase those properties that need to be relegated to a less-intensive land use. Liquefaction : Smith (1996, 129) states that liquefaction is "the process by which water-saturated sediments can temporarily lose strength, because of strong shaking, and behave as a fluid." During liquefaction, soil material transforms into a fluid mass and buildings can face subsidence and possible collapse. Planning strategies specifically targeted to liquefaction potential include the following: · Prohibit high-density development (residential or otherwise) in areas of clay or alluvial sediment unless the building foundations are embedded into the bedrock (Eisner et al., 1993). Previous landfill sites and lands reclaimed from the sea represent particular hazard. Various levels of building subsidence were observed during the Gölcük-İzmit site visits. · If liquefaction areas are already developed, encourage agricultural land uses requiring irrigation in adjacent areas so that the local water table can be lowered. Simultaneously, the use of the underlying aquifers as drinking and industrial water sources can also bring the water table down. Ultimately, these strategies represent a trade-off where the urban planner has to weigh costs against benefits. If the urban area is adjacent to a saltwater body, then caution must be exercised in manipulating the water table since this may permit the infiltration of freshwater with saltwater. Landslides : "The severe shaking in an earthquake can cause natural slopes to weaken and fail" (Smith, 1996: 130). Since landslides are more of a threat when the topography is hilly, the following strategies are important: · Minimize hillside development, unless the unstable slope issue is dealt with (e.g., the building code mandates that foundations must be anchored to the bedrock). · Preserve all natural drainage courses and maintain them in their original state. The use of engineering solutions to hide or redirect watercourses puts hilly topography at risk. · In all cases, there must be an attempt to recognize the importance of topography "Significant [wave] amplifications occur in steep topography, especially on ridge crests" (Smith, 1996: 129). Although grading should be minimized, if sloped areas are to be developed, then blend cut and fill slopes with the existing topography by using contour grading (Eisner et al., 1993). Flooding : The flooding implications of earthquakes can result from a variety of secondary effects, including tsunamies, seiches, the courses of rivers and streams being altered, groundwater being discharged out of its reservoirs, shorelines falling due to fracturing, and the failure of dams during seismic stress. Anecdotal observations in the Gölcük-İzmit area include those of a seiche at least seven meters in height being experienced immediately after the earthquake (McGrory, 1999). The Gölcük shoreline demonstrated extensive displacement and flooding. In fact, during October, 1999, the city's waterfront continued to remain submerged under meters of water. Planning strategies for flooding include the following: · Urban run-off systems need to be designed for the hundred-year storm or flood (e.g., design curbs, gutters and culverts to carry elevated levels of run-off). Debris basins can be constructed in valley floors and along water courses (Eisner et al., 1993). · If underwater or marine faults are an issue (e.g., in the Sea of Marmara), then development in low-lying coastal areas needs to be either prohibited or minimized. Even though waterfront development can represent highest and best use, low-lying coastal areas need to be developed according to flood plain management and the reach of the 100-year flood. Fire : Fire is an on-going threat during the aftermath of an earthquake. Following the Gölcük-İzmit earthquake, the largest petroleum refinery in Turkey (owned by Tüpraş) ignited. At the site level, gas lines can rupture and burn. Fire safety has a number of planning-related protocols: · Open space and open space system planning is a priority for minimizing fire-related hazard. Many cities throughout Turkey, including the Gölcük-İzmit area, have been developed at high density and with minimal dedicated parkland. Provision for open space serves a number of functions. First, open space provides a place for retreat both during and after the ground-shaking. Second, open space can slow the progress of emerging fires. Third, open space functions best when it is part of a system or network because the open space can then be used as an escape route if evasive movement across terrain is necessitated. Fourth, visual access to open space is psychologically important during the anxiety of ground-shaking. Finally, open space systems are optimized when they are networked to water bodies (e.g., streams, rivers, lakes or seas) since this improves their effectiveness in offering escape from aggressive fires and has the added benefit of increasing their contribution to urban biodiversity. · Accessibility for emergency fire-fighting vehicles and equipment is also a major concern at the site-level. As well, toxic flammables need to be stored in low-risk areas. CONCLUDING REMARKS For other urban areas in Turkey that face similar levels of seismic risk, the Gölcük-İzmit earthquake represents a window into the sort of catastrophic damage that may occur again unless settlement patterns become planned, and existing and improved building codes are rigidly applied. Many opportunities for improving the performance of Turkish buildings during and after an earthquake exist and need to be optimized. During periods of low seismic activity, stringent planning and building code requirements may appear to be excessive and are infrequently palatable in political terms. Consequently, the challenge is to maintain the political motivation to ensure best practices in land use planning and in building construction consistently across time. For governments to remain credible in earthquake-prone areas, tenable settlement patterns plus building code evolution and implementation must recognize seismic hazard. REFERENCES Abbott, Patrick. (1996) Natural Disasters. Dubuque, Iowa: Times Mirror Higher Education Group, Inc. ASCE (American Society of Civil Engineers). (1986) Urban Planning Guide. Revised Edition. New York: American Society of Civil Engineers. Eisner, Simon et al. (1993) The Urban Pattern. 6th Edition. New York: Van Nostrand Reinhold. Gorvett, Jon. (1999) "Turkey's Earthquake Nightmare" in Insight Turkey. 1/4: 133-143. Hodge, Gerald. (1991) Planning Canadian Communities: An Introduction to the Principles, Practice and Participants. 2nd Edition. Scarborough: Nelson Canada. Leung, Hok Lin. (1989) Land Use Planning Made Plain. Kingston: Ronald Frye and Company. McGrory, Daniel. (1999) "Families Wait for Mementos from 'Atlantis.'" Ottawa Citizen, August 25, 1999. A6. Oxford Business Group. (1998) "Turkey Can't Be Pigeon-holed" in Emerging Turkey: 1999. London: The Oxford Business Group. 10-11. Smith, Kevin. (1996) Environmental Hazards: Assessing Risk and Reducing Disaster. New York: Routledge. Tarbuck, Edward and Frederick Lutgens. (1997) Earth Science. 8th Edition. Upper Saddle River, New Jersey: Prentice-Hall. USGS (United States Geological Survey). (1999) http:// earthquake.usgs.gov/neis/eqlists/sig_1999 .html Zebrowski, Ernest. (1997) Perils of a Restless Planet: Scientific Perspectives on Natural Disasters. Cambridge: Cambridge University Press. |