In the equatorial Pacific Ocean, earthquakes are used as an indicator of tectonic stress
for normal faults in the Galapagos Spreading Center, transform faults along the East
Pacific Rise and thrust faults in the Middle American subduction zone. Linkages between
seafloor tectonic processes and oceanographic and lunar conditions were explored using
time-series cross-correlation analyses on two different time scales.
Data for earthquakes in the eastern tropical Pacific study area are obtained using the
hydrophone arrays of the NOAA-VENTS Program. Hydroacoustic monitoring (listening
to underwater sounds) provides scientists with a detailed dataset that includes even small
earthquakes, starting as low as magnitude 0.6, that are not perceived by land-based
seismographs. Data for sea surface heights (SSH) consist of two different datasets. On a
moon's quarter time scale, SSH data used to investigate the influence of the earth tide and
changes in oceanic conditions were remotely acquired by the altimeter on board the
TOPEX/Poseidon (T/P) satellite. SSH data used to investigate the influence of the ocean
tides were obtained from the Tidal Model Driver (Padman and Erofeeva 2003), that
predicts SSH for locations every hour. The Geographic Information System (GIS) was
used for the visual display of the data and to compute basic descriptive statistics. A lab-book
was created for the educational-outreach section of this work, explaining step by
step how GIS has been used.
Significant results show correlations between normal faults and ocean tides and
between the thrust fault and earth tides. Also, the Quebrada and the Discovery transform
faults show high correlation of earthquake events, suggesting that at such temporal and
spatial resolution, the plate moves as a rigid block. / Graduation date: 2006
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28473 |
| Date | 17 February 2006 |
| Creators | Zennaro, Barbara |
| Contributors | Duncan, Robert |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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