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Metadata Identifier: gov.noaa.ngdc.mgg.photos:G01230

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 Mount Pinatubo Revisited; A Study of Lahar Erosion At dawn on June 15, 1991, a cataclysmic eruption began with a tremendous explosion that destroyed ten deserted villages. This eruption deposited approximately 5 to 7 km3 of volcanic fragments in pyroclastic flows on the slopes of the volcano and over neighboring towns and agricultural areas. It is this material that continues to threaten structures and lives in the area, in the form of lahars (debris flows) during heavy rainstorms. The lahars from the Mount Pinatubo volcano have been particularly damaging to the surrounding area. This set of slides shows how the disaster that began at Pinatubo in 1991 continues to threaten the population in the area. Mount Pinatubo is located on the Island of Luzon in the Philippines, about 100 km northwest of Manila. The volcano, with K-Ar datings of approximately 1.1 million years, and with the youngest carbon-14 dating of + 400 years B.P. (before present), is the youngest volcano in the western Luzon volcanic arc. On April 2, 1991, Pinatubo, which had been rumbling for months, stirred to life. Over the next six weeks earth tremors and minor explosions occurred. These natural warnings led to the evacuation of personnel at Clark Air Base and of 55,000 people in nearby towns and villages. At dawn on June 15, 1991, a cataclysmic eruption began with a tremendous explosion that destroyed ten deserted villages. The eruption deposited approximately 5 to 7 km3 of volcanic fragments in pyroclastic flows on the slopes of the volcano and over neighboring towns and agricultural areas. It is this material that continues to threaten structures and lives in the area, inthe form of lahars (debris flows) during heavy rainstorms. The Pinatubo deposits are subdivided into two general groups based on the lithology and age of emplacement: the "ancestral" and the "modern." The ancestral Pinatubo (+/- 1 million to +/-35,000 years B.P.) is an andesite-dacite stratovolcano of mostly laval flows and breccia deposits oflaharic origin. On its slopes are numerous elongated to sub-rounded hills made up of breccia, created mostly by the ancestral lahars. The modern Pinatubo (+/- 35,000 years to present) shows signs of repeated, very explosive eruptions which have produced large volumes of pumiceouspyroclastic flows. Pyroclastic flows, also known as nuee ardentes, or glowing avalanches, are extremely hot (+/-1,000 degrees Celsius), often incandescent, highly fluid, gravity-driven density currents of gas and volcanic fragments that sweep down slope and travel at hurricane speed (+/-100 km per hour). Pyroclastic flows are generated when the density of the rising column of volcanic fragments and gas exceeds that of the surrounding atmosphere. Gravity causes a portion or all of the column to collapse and flow down the flanks of the volcano. Most of the 1991 pyroclastic flow deposits were emplaced during the June 15 eruption. The pre-eruption magma temperature of Pinatubo was about 800 degrees Celsius and the temperature of the emplaced pyroclastic flow was on the order of 600 degrees Celsius. The deposits are non-welded, dry, and very loose. The accumulated thickness of the pyroclastic flows varies, depending on the proximity to the crater and the pre-eruption morphology. It reaches more than 200 meters along deep pre-eruption valleys. The pyroclastic flow deposits of 1991 affected eight major watersheds around the slopes of the volcano and radically altered the hydrological regimes, leading to unprecedented amounts of erosion and sediment delivery in the form of destructive lahars. Lahars predominantly occur during the rainy season in the monsoon period, which lasts from June until November. Long-duration and high-intensity rainfall, associated with the occurrence of strong typhoons, are responsible for the production of large-magnitude lahars. Other factors contributing to the rapid erosion of lahars are: failure of lahar dams, secondary explosions produced by rapid vertical and lateral erosion of the pyroclastic flow deposits, and stream and river capture bringing deposits into new drainage systems. The rapid erosion or removal of the pyroclastic flow deposits has been one of the major social and scientific concerns after the 1991 eruption ofthe Pinatubo Volcano. The lahars from Pinatubo have resulted in loss of lives and damage to properties in areas surrounding the volcano. About 500,000 persons were left homeless and indirect impacts such as flooding and isolation have affected more than 1.3 million people in 39 different towns and four large cities. About 1,000 km2 of prime agricultural lands are atrisk. Lahars will continue to be an important hazard on the lower slopes of Pinatubo for a number of years.
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CI_Citation

Count Component Title Date Citation Identifier
1 Container Packet ID
    1 Getty Thesaurus of Geographic Names
      1 INFOTERRA Keyword Thesaurus
        1 Mount Pinatubo Revisited; A Study of Lahar Erosion
          1994
        Document
        1 GCMD Data Center Keywords NASA/GCMD Data Center Keywords
          2015-03-01
          1995-04-24
        1 NASA/GCMD Earth Science Keywords
          1 GCMD Project Keywords NASA/GCMD Project Keywords
            2015-03-01
            1995-04-24
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          CI_Series

          none found
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          CI_ResponsibleParty

          Count Component Individual Organization Position Email Role Linkage
          2 GCMD Valids http://gcmd.nasa.gov/learn/keyword_list.html
          1 Anna Milan Anna Milan DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce Metadata Specialist Anna.Milan@noaa.gov pointOfContact
          1 NCEI (publisher) DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce publisher
          1 NCEI User Services (distributor) DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce User Services ngdc.info@noaa.gov distributor
          3 Hazards Data Manager (pointOfContact) DOC/NOAA/NESDIS/NCEI> National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce Hazards Data Manager haz.info@noaa.gov pointOfContact
          1 DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce (comp) originator
          2 GCMD User Support Office NASA GCMD User Support Office gcmduso@gcmd.gsfc.nasa.gov publisher http://gcmd.nasa.gov/MailComments/MailComments.jsf?rcpt=gcmduso
          1 National Geophysical Data Center publisher
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          CI_OnlineResource

          Count Component Linkage Name Description Function
          2 http://gcmd.nasa.gov/MailComments/MailComments.jsf?rcpt=gcmduso GCMD Feedback Form Have a Comment for the GCMD? information
          2 http://gcmd.nasa.gov/learn/keyword_list.html GCMD's Science Keywords and Associated Directory Keywords This page describes the NASA GCMD Keywords, how to reference those keywords and provides download instructions. information
          1 http://www.ngdc.noaa.gov/hazard/
          2 http://www.ngdc.noaa.gov/nndc/struts/results?eq_1=36&t=101634&s=0&d=4&d=44
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          MD_Identifier or RS_Identifier

          Count Component Code
          1 Document
          1 G01143
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          EX_Extent

          Bounding Box Temporal Extent
          Count Component Description West East North South Start End
          1 120.21 120.21 15.08 15.08 1991-04-02 1993-10-06
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          EX_GeographicBoundingBox

          Count Component West East North South
          1 120.21 120.21 15.08 15.08
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          EX_TemporalExtent

          Count Component Start End
          1 1991-04-02 1993-10-06
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          MD_Format

          Count Component Name Version specification
          2 TIFF
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          MD_Medium

          Count Component Name mediumFormat mediumNote
          1 cdRom iso9660
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          MD_Constraints

          Count Component Use Limitation
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          MD_ReferenceSystem

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          MD_GridSpatialRepresentation

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          MD_Georeferenceable or MI_Georeferenceable

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          MD_Georectified or MI_Georectified

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          MD_Dimension

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          MD_CoverageDescription or MI_CoverageDescription

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          MD_Band or MI_Band

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          MI_RangeElementDescription

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          MD_AggregateInformation

          Count Component Title Code Association Type Code
          1 G01143 largerWorkCitation
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          LE_Source or LI_Source

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          LE_ProcessStep or LI_ProcessStep

          Count Component DateTime Description
          1 2015-04-22T00:00:00 NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
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