Mapping Mantle Structure
{'Code': '06030204', 'Directorate': {'Abbreviation': 'GEO', 'LongName': 'Directorate For Geosciences'}, 'Division': {'Abbreviation': 'EAR', 'LongName': 'Division Of Earth Sciences'}}
{'SignBlockName': 'Patricia Brooking', 'PO_EMAI': 'pbrookin@nsf.gov', 'PO_PHON': '7032924728'}
A program of continuing application of waveform modeling to                     recover the detailed nature of the boundaries in the earth is                   proposed.  It is based on an ability to model and thereby                       interpret the considerable complications of observed record                     sections caused by propagation through a complex earth.                                                                                                         We propose to develop P and S velocity models from broad-band                   data with boundaries constrained to be at the same depths for                   the most uniform regions, shields, young and old oceans, and                    detailed two-dimensional cross-sections through regions of                      rapid variations.  The recent tomographic results can be used                   to great advantage in collecting key data-sets where complete                   seismic sections, including surface waves, can be compared with                 synthetics appropriate for laterally varying earth models and                   proper evaluations made.  Effects on surface waves due to                       lateral variation will be examined by applying a modified                       generalized ray code and by a finite-difference code modified                   to treat earthquake sources with three-dimensional spreading.                                                                                                   The well established teleseismic travel time and amplitude                      (WWSSN long period) fluctuation patterns will be examined by                    comparing synthetics for the appropriate paths taken from                       detailed whole mantle tomographic results such as Grand (1986).                 This testing of proposed models will be conducted on core-mantle                phases as well as the usual direct P and S waves.  Particular                   attention will be given to (SKS - Sdif) seismic sections which                  show considerably more scatter from region-to-region than can                   be easily explained by variations in the mantle alone.
{'FirstName': 'Donald', 'LastName': 'Helmberger', 'PI_MID_INIT': 'V', 'PI_SUFX_NAME': None, 'PI_FULL_NAME': 'Donald V Helmberger', 'EmailAddress': 'helm@gps.caltech.edu', 'NSF_ID': '000382799', 'StartDate': '08/01/1987', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'California Institute of Technology', 'CityName': 'PASADENA', 'ZipCode': '911250001', 'PhoneNumber': '6263956219', 'StreetAddress': '1200 E CALIFORNIA BLVD', 'StreetAddress2': None, 'CountryName': 'United States', 'StateName': 'California', 'StateCode': 'CA', 'CONGRESSDISTRICT': '28', 'CONGRESS_DISTRICT_ORG': 'CA28', 'ORG_UEI_NUM': 'U2JMKHNS5TG4', 'ORG_LGL_BUS_NAME': 'CALIFORNIA INSTITUTE OF TECHNOLOGY', 'ORG_PRNT_UEI_NUM': None}
{'Name': None, 'CityName': None, 'StateCode': None, 'ZipCode': None, 'StreetAddress': None, 'CountryCode': None, 'CountryName': None, 'StateName': None, 'CountryFlag': None, 'CONGRESSDISTRICT': None, 'CONGRESS_DISTRICT_PERF': '""'}
{'Code': '1574', 'Text': 'Geophysics'}
{'url': 'https://www.nsf.gov/awardsearch/download?DownloadFileName=1987&All=true', 'xml': '8707709.xml'}