A Study of Mantle Layering Using First-Order Reverberations
{'Code': '06030204', 'Directorate': {'LongName': 'Directorate For Geosciences'}, 'Division': {'LongName': 'Division Of Earth Sciences'}}
{'SignBlockName': 'James H. Whitcomb'}
Two years of funding are requested to support a study of mantle            layering using the first-order mantle reverberations recently                   discovered by Revenaugh and Jordan (1987a).  Waves of this type                 specifically sub-critical reflections from the 400-km and                       650-km discontinuities, have been observed as discrete seismic                  pulses on SH-polarized seismograms following ScSn wavegroups.                   We propose to compile an extensive set of mantle reverberations                 from GDSN recordings and to employ this data set: (1) to map                    regional variations in (a) vertical travel time through three                   mantle layers (0-400 km, 400-650 km, 650-2890 km), (b) vertical                 attenuation through two mantle layers (0-650 km, 650-2890 km), and              (c) the reflection coefficient of the 650-km discontinuity;                     (2) to search for additional discontinuities in both the upper                  and lower mantle; and (3) to investigate the role of incoherent                 scattering in the apparent attentuation of ScSn waves.
{'FirstName': 'Thomas', 'LastName': 'Jordan', 'EmailAddress': 'tjordan@usc.edu', 'StartDate': '02/01/1988', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'Massachusetts Institute of Technology', 'CityName': 'Cambridge', 'ZipCode': '021394301', 'PhoneNumber': '6172531000', 'StreetAddress': '77 MASSACHUSETTS AVE', 'CountryName': 'United States', 'StateName': 'Massachusetts', 'StateCode': 'MA'}
[{'Code': '1574', 'Text': 'GEOPHYSICS'}, {'Code': '2674', 'Text': None}]
{'url': 'https://www.nsf.gov/awardsearch/download?DownloadFileName=1987&All=true', 'xml': '8708548.xml'}