Premium
Site response across downtown Santa Cruz, California
Author(s) -
Cranswick Edward,
King Kenneth,
Carver David,
Worley David,
Williams Robert,
Spudich Paul,
Banfill Robert
Publication year - 1990
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl017i010p01793
Subject(s) - geology , alluvium , seismometer , downtown , aftershock , seismology , flood myth , floodplain , basement , geomorphology , sedimentary rock , alluvial plain , hydrology (agriculture) , archaeology , paleontology , geotechnical engineering , geography , cartography
Some buildings in Santa Cruz, California, particularly those in the downtown section which is built on a flood plain, were severely damaged by the 17 October 1989 Loma Prieta Earthquake. During an aftershock study conducted in the fortnight following the mainshock, an array of seismographs was deployed across downtown to study the site response of the flood plain. Analyses of the records of eight aftershocks reveal that ground motions of the flood plain are amplified relative to those of crystalline rock sites by factors of 4–8 in the frequency band 2–8 Hz. Both resonance in the whole sedimentary column which overlies the crystalline basement and resonance/broad‐band amplification in the low‐velocity alluvium of the flood plain contribute to this site response.