ISO Table View Alternate Views: Get Data, FAQ, ISO Rubric, DOI Rubric, CSW, HTML, Components, XML

Metadata Identifier: gov.noaa.ngdc.mgg.photos:G01196

Aggregation Info | Bands | Citations | Constraints | Coverage Descriptions | Dimensions | Extents | Formats | Geographic Bounding Box
Georectified Information | Georeferenceable Information | Identifiers | Instruments | Mediums | OnlineResources | Operations
Platforms | Process Steps | Range Elements | Reference Systems | Responsible Parties | Series | Sources | Spatial Grids | Temporal Extents

MD_DataIdentification

Count Component Title Abstract
1 Earthquake Damage in Mexico City, Mexico, September 19, 1985 On September 19, 1985, a magnitude 8.1 earthquake occurred off the Pacific coast of Mexico. The damage was concentrated in a 25 km2 area of Mexico City, 350 km from the epicenter. The underlying geology and geologic history of Mexico City contributed to this unusual concentration of damage at a distance from the epicenter. Of a population of 18 million, an estimated 10,000 people were killed, and 50,000 were injured. In addition, 250,000 people lost their homes and property damage amounted to $5 billion. This set of slides shows different types of damaged buildings and the major kinds of structural failure that occurred in this earthquake including collapse of top, middle and bottom floors and total building failure. The effect of the subsoils on the earthshaking and building damage are emphasized. Over 800 buildings crumbled, including hotels, hospitals, schools, and businesses. Communications between Mexico City and the outside world were interrupted for many days. Surrounding areas affected by the earthquake included the Mexican States of Jalisco, Guerrero, and Michoacan. Damage in the epicentral area wasrestricted to a few tourist resorts and industrial estates along the Mexico Pacific coast. A two-meter tsunami also caused some damage in this area. There are geologic reasons why Mexico and especially Mexico City are vulnerable to earthquake damage. Along the west coast of southern Mexico and Central America, the Cocos Plate dips beneath the North American Plate producing a very active seismic zone. Since the beginning of the Twentieth Century, 84 earthquakes of magnitude greater than 7.0 have occurred in this zone. The location of the 1985 earthquake's epicenter near the coast at the border between the states of Michoacan and Guerrero was not a surprise. Prior to the 1985 earthquake this area, located between two areas that had experienced recent earthquakes, was known as the "Michoacan Gap." The "gap" was filled in 1985 by the main shock and a severe aftershock (magnitude 7.5) that occurred two days later, on September 21. Mexico City lies in a broad basin formed approximately 30 million years ago by faulting of an uplifted plateau. Volcanic activity closed the basin and resulted in the formation of Lake Texcoco. The Aztecs chose an island in this lake as an easily defended location for their capitol. The expansion of Mexico City and the gradual draining of the lake left the world's largest population center located on unconsolidated lake-bed sediments. These soft sedimentary clay deposits amplified the seismic waves, or they liquefied, destroying the foundation of some buildings. Double resonance coupling between the earthquake waves, the subsoils, and the buildings caused intensity IX shaking in some areas, lasting up to three minutes. Earthquakes in 1957 and in 1979 also damaged Mexico City. However, neither of these earthquakes was quite as devastating as the 1985 earthquake. In the area of greatest damage in downtown Mexico City, some types of structures failed more frequently than others. In the highest damage category were buildings with six or more floors. Resonance frequencies of these buildings were similar to the resonance frequencies of the subsoil. Because of the unusual flexibility of Mexico City structures, upper floors swayed as much as one meter and frequently collapsed. Differential movements of adjacent buildings also resulted in damage. A flexible building often failed if it was held by adjacent, more rigid lower buildings. Damage or failure often occurred where two swaying buildings came in contact with each other. Corner buildings were also vulnerable to damage. Lessons learned from the patterns of earthquake damage need to be applied to prevent another disaster when an earthquake releases stress that is building in another area-along the Mexico coast between Acapulco and Zihuatanejo.
Top

SV_Identification

none found
Top

CI_Citation

Count Component Title Date Citation Identifier
1 Earthquake Damage in Mexico City, Mexico, September 19, 1985
  • 1994
Document
1 Getty Thesaurus of Geographic Names
    1 INFOTERRA Keyword Thesaurus
      1 NASA/GCMD Data Center Keywords
        1 NASA/GCMD Earth Science Keywords
          Top

          CI_Series

          none found
          Top

          CI_ResponsibleParty

          Count Component Individual Organization Position Email Role Linkage
          1 DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce (comp) originator
          1 Heather McCullough DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce Heather.McCullough@noaa.gov http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_RoleCode
          1 Heather McCullough DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce Heather.McCullough@noaa.gov pointOfContact
          1 Heather McCullough DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce Heather.McCullough@noaa.gov custodian
          1 National Geophysical Data Center publisher
          1 User Services DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce ngdc.info@noaa.gov distributor
          Top

          CI_OnlineResource

          Count Component Linkage Name Description Function
          1 http://www.ngdc.noaa.gov/hazard/
          1 http://www.ngdc.noaa.gov/hazardimages/event/show/13
          Top

          MD_Identifier or RS_Identifier

          Count Component Code
          1 Document
          Top

          EX_Extent

          Bounding Box Temporal Extent
          Count Component Description West East North South Start End
          1 -99.09 -99.09 19.24 19.24 1985-09-19 1985-09-21
          Top

          EX_GeographicBoundingBox

          Count Component West East North South
          1 -99.09 -99.09 19.24 19.24
          Top

          EX_TemporalExtent

          Count Component Start End
          1 1985-09-19 1985-09-21
          Top

          MD_Format

          Count Component Name Version specification
          1 TIFF
          Top

          MD_Medium

          Count Component Name mediumFormat mediumNote
          1 cdRom iso9660
          Top

          MD_Constraints

          Count Component Use Limitation
          Top

          MD_ReferenceSystem

          none found
          Top

          MD_GridSpatialRepresentation

          none found
          Top

          MD_Georeferenceable or MI_Georeferenceable

          none found
          Top

          MD_Georectified or MI_Georectified

          none found
          Top

          MD_Dimension

          none found
          Top

          MD_CoverageDescription or MI_CoverageDescription

          none found
          Top

          MD_Band or MI_Band

          none found
          Top

          MI_RangeElementDescription

          none found
          Top

          MD_AggregateInformation

          none found
          Top

          LE_Source or LI_Source

          none found
          Top

          LE_ProcessStep or LI_ProcessStep

          none found
          Top

          MI_Operation

          none found
          Top

          MI_Platform

          none found
          Top

          MI_Instrument

          none found
          Top