The Rupture Mode of Earthquakes and Fault Zone Properties                                                                                             >
{'Code': '06030204', 'Directorate': {'Abbreviation': 'GEO', 'LongName': 'Directorate For Geosciences'}, 'Division': {'Abbreviation': 'EAR', 'LongName': 'Division Of Earth Sciences'}}
{'SignBlockName': 'Patricia Brooking', 'PO_EMAI': None, 'PO_PHON': None}
This study emphasizes the relationship between the rupture mode of              earthquakes and the nature and distribution of heterogeneities along a          fault plane.  A primary objective is to determine whether                       heterogeneities are structural features or are features induced by              stress and slip variations that change with time.  We will investigate          the rupture mode of earthquakes relative to the fault heterogeneities           through analysis of waveforms of the largest events and their                   aftershocks.                                                                                                                                                    Heterogeneities are mapped along the length and depth of a fault plane          by analyzing refracted waves generated by local seismicity.  This               information reflects the velocity contrast between differing materials          that are juxtaposed in the fault zone.  Our analyses reveal that the            velocity contrasts are not randomly distributed, but rather occur in            patches where one range of values predominates.                                                                                                                 We propose to extend our dataset of relocated earthquakes and to refine         the refraction angle analyses for mapping patches of velocity contrast.         Finite-difference modeling of the waveforms will better define the              nature of the heterogeneities that are mapped by refraction analysis.           Preliminary results indicate that the largest earthquakes in the study          region (San Andreas fault, central California) since 1936 nucleate in           the vicinity of small patches with high variance of velocity contrast           and rupture into larger patches of more homogeneous velocity contrast.          Combined with waveform analysis of the mainshocks, we may be able to            characterize fault zone heterogeneities and the mainshock rupture               process to a greater degree than has previously been done.
{'FirstName': 'Karen', 'LastName': 'McNally', 'PI_MID_INIT': 'C', 'PI_SUFX_NAME': None, 'PI_FULL_NAME': 'Karen C McNally', 'EmailAddress': None, 'NSF_ID': '000445240', 'StartDate': '07/01/1987', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'University of California-Santa Cruz', 'CityName': 'SANTA CRUZ', 'ZipCode': '950641077', 'PhoneNumber': '8314595278', 'StreetAddress': '1156 HIGH ST', 'StreetAddress2': None, 'CountryName': 'United States', 'StateName': 'California', 'StateCode': 'CA', 'CONGRESSDISTRICT': '19', 'CONGRESS_DISTRICT_ORG': 'CA19', 'ORG_UEI_NUM': 'VXUFPE4MCZH5', 'ORG_LGL_BUS_NAME': 'UNIVERSITY OF CALIFORNIA SANTA CRUZ', 'ORG_PRNT_UEI_NUM': None}
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{'Code': '157400', 'Text': 'Geophysics'}
{'url': 'https://www.nsf.gov/awardsearch/download?DownloadFileName=1987&All=true', 'xml': '8708034.xml'}