Akademik Veri Yönetim Sistemi
20th Anniversary of the 1999 Marmara Earthquakes: 23rd Active Tectonics Research Group Meeting, İstanbul, Türkiye, 15 - 18 Ekim 2019, cilt.1, sa.1, ss.128, (Tam Metin Bildiri)
The multiple reflections are created by the seismic signal traveling to same
way more than one can create difficulties in marine geophysics studies in shallow
water. Since the sea floor is so powerful reflector, it reflects great part of the coming
signal. This reflected signal reflecting back from the surface of sea-air reaches again
to the seafloor. This condition depending on water depth, power of source and record
length can repeat itself several times. Multiple reflections may cause difficulties in
data processing and misinterpretation of data. Interference of multiples with the
primary reflections can cause inaccuracy in data processing and interpreting.
Constructive interference can cause that amplitude of the primary reflections to be
seen higher than it is, but distractive interference can cause that amplitude of primary
reflections to be seen lower than it is. Knowing the differences between multiples and
primary reflections is very important to remove multiples. Removing multiples
during data acquisition is not possible. For this reason, many methods have been
developed in data processing to remove multiples from data. In this study, besides
routine data processing, predictive deconvolution and f-k filter were applied to data.
This multichannel seismic data was processed using Paradigm® Echos® software in
“Seismic Data Processing Laboratory” at the Department of Geophysical
Engineering Istanbul University-Cerrahpasa. Routine data processing steps are; data
loading, geometry definition, editing, muting, gain recovery, band pass filtering, CDP
sorting, velocity analysis, NMO correction, stack and migration. In this study, the
methods used in removing multiples from seismic data are discussed. First of all,
predictive deconvolution was applied to data using DECONA module in Echos
software. The parameters using in predictive deconvolution were compared with each
other and then the parameter that gives the best result was selected. Also, the f-k filter
was applied to multichannel seismic data as two separate techniques by using
FKFILT and ZMULT module in Echos software. The aim of this study is to compare
these methods used for removing multiples with each other and determine the method
that gives the best result according to stack sections