WITHDRAWN Ambient Noise Interferometry to Obtain Images of the Mid- and Lower Crust
Description:
WITHDRAWN Conventional seismic reflection imaging techniques using ambient seismic noise require extraction of seismic reflection response using seismic interferometry. Additional processing steps include CDP sorting and migration are required to obtain a reliable image of the subsurface. However, these traditional techniques have difficulty in imaging the mid and lower crust.
We use the data from a large-N seismic survey conducted in March 2014 near Sweetwater, TX, which consisted of 2639 receiver locations using Z-land 1C nodes from Nodal Seismic. These short period instruments recorded signals from a Vibroseis source truck for 11 days. We identify the period when Vibroseis sources were active and split the data into two subsets: data recorded with and without Vibroseis sources. We further split the data without Vibroseis sources into three smaller subsets with an increasing recording period of 4, 5, and 6 hours starting at 11:00 pm CST. We experiment with different processing parameters including frequency range, time/frequency normalization, cross-correlation and step length, and maximum time lag to find optimum parameter values and obtain virtual source gathers for all subsets of data.
We used stacks of near-offset traces from virtual source gathers to form a gather equivalent to a zero-offset reflection section. Various sizes of the stacking bins were tested to determine trade-offs between lateral resolution of the image and contamination from random noise. A P-wave reflectivity image was then obtained by minimizing the masking effect of the effective source time function. A comparison between primary results obtained for the data subsets with and without Vibroseis sources indicates that comparable images of the deeper subsurface can be obtained without the use of Vibroseis sources. Images improve, in the sense that they become better and better approximations of the Vibroseis image, upon increasing the recording duration.
Session: Crustal Imaging of High Seismic Hazard Regions [Poster]
Type: Poster
Date: 4/20/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Yashwant Soni
Student Presenter: Yes
Invited Presentation:
Authors
Yashwant Soni Presenting Author Corresponding Author yashwant_soni1@baylor.edu Baylor University |
Jay Pulliam jay_pulliam@baylor.edu Baylor University |
|
|
|
|
|
|
|
WITHDRAWN Ambient Noise Interferometry to Obtain Images of the Mid- and Lower Crust
Category
Crustal Imaging of High Seismic Hazard Regions