Chincha and Cañete, Peru, Based

Transcription

1 Reconstruction of Ica, Pisco, Chincha and Cañete, Peru, Based on Updated Hazard Maps Julio Kuroiwa Professor emeritus National University of Engineering and UNDP Reconstruction Program/Sustainable Cities. Peru.

2 Proposal of a Sustainable City (SC) In view of the growing unplanned urban develop- ment taking place, in developing countries which makes cities: risky, inefficient & hostile. A proposal of a sustainable city was made, defined as: Safe, orderly, healthy, attractive, efficient, environ- ment-friendly, appreciative of its cultural-historic heritage and therefore, governable and competitive.

3 Strategy to Develop a Sustainable Cities Program (SCP) Focus the SCP on the SC s first attribute: Its physical safety: (SCP-1S) Carry out priority actions in the short term protecting ti life and properties. Develop an urban plan based on the hazard map. The final goal is to achieve a competitive city.

4 Hazard Map Based on the traditional microzonation methods and techniques with a multihazard approach. A typical team has the following specialties: geology, soil mechanics, hydrology/hydraulics, y environment, GIS. If other specialists are needed, they are included, e.g. an expert on tsunamis, for Pisco and Tambo de Mora located on the sea shore. Team leader is usually an urban planner or architect, closer to the population s p social needs than engineers, and better able to produce a friendly document for the next users.

5 Statistical Data of Mexico s Earthquakes Showing Microzonation Effects Accelerograms recorded on the coast near the epicenter and in Mexico City, 300 km from the EQ. Soruce Ref. UNAM

6 Seismic wave amplification on soft soil Ratio of acceleration on rock and on soft soils. (Ref. Idriss. 1991) Amplification of the horizontal peak acceleration for different types of soil according to Seed, et al., 2001.

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8 Natural Hazard and Land Use Planning Restrictions DEGREE OF RESTRICTIONS AND CHARACTERISTICS EXAMPLES HAZARD RECOMMENDED USAGE Forces of nature are so Sectors threatened by landslides, Not permitted for urban use. strong that man-made made avalanches, and sudden flows of mud Recommended for open air 1. HIGHLY constructions cannot and rocks. recreation. HAZARDOUS withstand them. Soils with high probability of (Red) Losses reach 100%. widespread liquefaction or soils that Cost benefit ratio rules out are collapsible in large proportions. its use for urban purposes. Effective damage- reduction measures can Strips adjacent to very-high hazard sectors, but the hazard remains high. Detailed studies by experienced specialist. be taken at reasonable Sectors where high seismic Recommendable for low- 2. HAZARDOUS costs. acceleration is expected and slowly density urban use. (Orange) become inundated. Adobe construction is not Partial occurrence of liquefaction and permitted expansive soils. Moderate natural threat. Soil of intermediate quality, with Suitable for urban use. 3. MEDIUM (Yellow) moderate seismic accelerations. Very sporadic flooding with little depth or Normal geotechnical studies required. speed. Low amplification of seismic waves. Flat or gently sloping land, rock or compact dry soil, with high load Ideal for high-density urban use and the location of 4. LOW Very remote possibility of capacity. essential buildings such as (Green) intense natural High-lying non-floodable land, at a hospitals, schools, police phenomena or gradual soil distance from cliffs of unstable hills. stations, fire station, etc. failure. Not threatened by volcanic activity or tsunamis. From Page 41. Kuroiwa, 2004.

9 1 Hazard Map (1), Land Use Plan (2), and Disaster Mitigation Projects (3), for Sullana Damage in La Quebrada in Hazard Map for Sullana The canal freeway along La Quebrada in 1998

10 Hazard Map (1), Land Use Plan (2), and Disaster Mitigation Projects (3), for Sullana Land-use Plan for Sullana, New bridge. 3

11 From 11/1998 to 06/2008, 133 cities and towns with 6.4 million inhabitants have been studied. Agreements have been signed with participating local national universities:.in 10 years some 80 consultants have been trained on the job.

12 Background: Three Disasters Between 1997 and 2007, Three Opportunities The SCP-1S started in November 1998 when there was the need to reconstruct Peru s NW cities devastated by El Niño The SCP-1S was expanded all over the country from Peru s SW, struck by the 2001 earthquake. Following the Ica region or Pisco EQ (15/08/2007), local, regional & central government e authorities made the consensual decision to use the hazard maps of the main affected cities for their reconstruction.

13 Validation of the Hazard Maps of Ica, Pisco, Chincha and Cañete The strategy - to obtain the necessary data and to effectively reach the affected communities - was drawn up as follows: Reviewing and updating the hazard maps, using also the advantage that the data were there in the large full-scale laboratory, i.e. the macroseismic area. Adding those towns that suffered severe damage during the 2007 event, and which had not been included in the previous studies. Intensifying the communication and coordination with local communities and authorities to capture their vision of cities for future generations, and let them know the dramatic advantage if hazard maps and disaster mitigation measures are included in their socio- economic development projects.

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16 VALIDATED HAZARD MAP OF ICA For essential facilities

17 Short Column Failures - SC Long Column Short Column

18 The left building was designed with the 1977 Seismic Code. The right one with the new 1997 Seismic Code. Ica Region or Pisco EQ, San Jose de los Molinos, Ica, Peru.

19 VALIDATED HAZARD MAP OF CHINCHA

20 Soil Liquefaction in Tambo de Mora Settlement of some 2.6 feet (0.8 m) Lateral spread. The right wall has moved to the right and towards the reader, opening a door. House settlement and floor cracks Sand volcano

21 Lessons learned from El Niño , 98 Arequipa 2001 EQ and Ica Region 2007 EQ, focusing those events on roads/bridges and domestic water supply, which suffered the most.

22 Effects of El Niño in Peru`s NW region Erosion caused by the force of the water in one of the gullies crossing the Pan- American Highway PAH, in northern Peru. Detail of the failure in the PAH due to a gully perpendicular to its axis (photo 1998) Failure of a bridge to the south of Tumbes, Peru. El Niño Trees and branches diverted the water and caused erosion nearby. Tumbes. 1998

23 Damage caused by El Niño to the PAH, in the stretch from Sullana to Desvio Talara, Peru.

24 Arequipa 2001 Earthquake Damage to the South Pan-American Highway and other roads caused by the 2001 Arequipa earthquake was concentrated in crossings with rivers, and where the unconfined road fills were over 13 feet (4m.) high.

25 Concluding Remarks Local site characteristics: soil, geology and topography have strong influence on the seismic i damage degree and its geographic distribution. Roads and domestic water distribution systems suffered the most during Peru s 2001 & 2007 earthquakes and El Niño & With effective application of hazard maps & earthquake resistant techniques, damage on brick masonry and reinforced concrete buildings may be reduced to less than 5% of their values.

26 THANK YOU