Application of the two-dimensional continuous wavelet transforms to imaging of the Shatsky Rise plateau using marine seismic data
Application of the two-dimensional continuous wavelet transforms to imaging of the Shatsky Rise plateau using marine seismic data (in The origin, evolution, and environmental impact of oceanic large igneous provinces, Clive R. Neal (editor), William W. Sager (editor), Takashi Sano (editor) and Elisabetta Erba (editor))
Special Paper - Geological Society of America (April 2015) 511: 127-146
- basalts
- elastic waves
- equations
- geometry
- geophysical methods
- geophysical profiles
- geophysical surveys
- igneous rocks
- intrusions
- large igneous provinces
- lava
- marine methods
- mid-ocean ridge basalts
- multichannel methods
- noise
- North Pacific
- Northwest Pacific
- Pacific Ocean
- processes
- seismic coherency
- seismic methods
- seismic profiles
- Shatsky Rise
- surveys
- traveltime
- two-dimensional models
- volcanic rocks
- volcanism
- wavelets
- West Pacific
- Helios Basin
- Ori Massif
- Tamu Massif
The Shatsky Rise, located in the northwest Pacific Ocean, is one of the largest oceanic plateaus. The origin and evolution of the oceanic plateaus are unclear because these features are remote and poorly imaged with geophysical data. Marine multichannel seismic (MCS) data were collected over the Shatsky Rise to image its upper crustal structure. These data have the potential to improve understanding of the processes of basaltic volcanism and the formation and evolution of oceanic plateaus by providing direct insights into the geometry and distribution of igneous eruptions. In contrast to sedimentary settings, it is often difficult to interpret deeper layers within basaltic crust because of rugged layering and scattering. Reflections in igneous crust are characterized by poor lateral continuity compared with marine sediments and often by weak impedance contrasts, resulting in a lower signal-to-noise ratio and a more challenging interpretation. In this paper we apply the two-dimensional (2-D) anisotropic continuous wavelet transform (CWT) method to improve interpretations of MCS data from the Shatsky Rise oceanic plateau. Applying the transform to the time domain MCS profiles with appropriate values of wavelength and period produces new images with enhanced continuity of reflectors and reduced amplitudes of incoherent noise at different periods. The analysis of the results obtained by using 2-D CWT on the MCS data over the Tamu massif part of the Shatsky Rise also helps reveal features such as dome-like bulges possibly associated with lava intrusion and faults in the deeper part of the crust associated with volcanic rock. These were not readily seen in the original seismic images, but the suppression of random noise and other signals with low coherence makes their interpretation possible. These and similar results provide new insights into the complexity of the igneous processes forming the Tamu massif.
