WDC for Geophysics, Beijing(中国地球物理学科中心)
 
   

Author-submitted data information


ID 725
Title Lg, pre-Pn noise, and pre-Lg phase noise waveforms, single- and two-station Lg amplitude data, and a broadband Lg attenuation model in the southeastern Tibetan Plateau
Creator Xi He
Subject Seismic Lg waveforms, Pre-Pn and pre-Lg phase noises, Seismic Lg amplitude data, Lg attenuation model
Publisher Xiukuan Zhao
Description To explore the crustal Lg-wave attenuation and its implications for regional crustal deformations in the southeastern Tibetan Plateau, we selected 134 crustal earthquakes occurring in the southeastern Tibetan Plateau during January 2007 and May 2016 with magnitudes between 4.4 and 6.4, which were recorded at 1034 permanent and portable stations. We collected the vertical-component waveforms from the China Earthquake Networks Center (CENC), China Earthquake Data Center (CEDC), and Incorporated Research Institutions for Seismology Data Management Center (IRIS). We performed the Lg attenuation tomography based on the single- and two-station Lg amplitude data. To obtain the spectral Lg amplitudes, we first extract the Lg waveforms in a group velocity window with a length of 0.6 km/s within the range of 2.8–3.7 km/s. Then, pre-Pn noise and pre-Lg phase noise were picked, respectively. These Lg and noise waveforms are provided in the “Lg_waveform” directory. Lg spectra were screened based on both the pre-event and pre-phase signal-to-noise ratio thresholds of 2.0 and 1.0, respectively. Last, the single-station Lg data were obtained after correcting for the pre-event noises, and the two-station Lg data were obtained from the single-station data for the roughly aligned triples of event and station-pair. The resulting Lg data is provided in the “sott” directory. Based on the single- and two-station Lg amplitude data, we performed a Lg attenuation tomography to obtain the regional Q model, which is provided in the LgQ.txt file. All material is compressed in the “SET_Lg_Amp_Attenuation.zip”.
Contributor Lian-Feng Zhao, Xiao-Bi Xie, Tong Lu, Zhen-Xing Yao
Date 2007-2016
Type All Lg and noise waveforms are stored in the standard SAC format. The Pn amplitudes were sampled at 58 frequencies distributed log-evenly between 0.05 and 10.0 Hz. Therefore, the spectral Lg amplitude data were provided in 58 separate files, with each file corresponding to one frequency indicated by the double-digit number in the file name.
Format In the “sott” directory, all Lg amplitude data, including single-station amplitudes and two-station amplitude ratios, were stored in the ASCII sott.*.dat files. The correspondence between the frequency and the double-digit number can be looked up in the file “frequency.txt”. The sott.*.dat files consist of header lines and data lines. Zero value in the 5th column indicates that the current line is the header line for single-station data, with the first two columns being the longitude and latitude of the recorded event, 3rd column being the number of lines of the following data, and 4th column being the sequence number of the recorded event. The header lines for single-station data are immediately followed by lines of single-station data, with the columns successively being the longitude and latitude of the recording station, Lg amplitude, geometric spreading term, and sequence number of the recording station. Zero value in the 4th column indicates that the current line is the header line for two-station data, with the first two columns being the longitude and latitude of the recording station, 3rd column being the number of lines of the following data, and 4th column being the sequence number of the recording station. The header lines for two-station data are immediately followed by lines of two-station data, with the columns successively being the longitude and latitude of the in-between station, the inter-station ratio of Lg amplitude, the geometric spreading term, and the sequence number of the in-between station.
“LgQ.txt” provides the resulting Lg attenuation model in the ASCII format, with the columns being the longitude, latitude, frequency, and Q-value.
In the “waveform” directory, each subdirectory corresponds to one event. Within each event directory, the “SAC” files contain Lg and noise waveforms, with the file name indicating the network, station, and location. All waveforms are corrected for instrumental response. The time window for picking the pre-Pn noise, pre-Lg phase noise, and Lg is marked using user-defined header variables t1–t6. Other parts of the waveform that were not used in this study are filled with float 0.
URL http://www.geophys.ac.cn/ArticleData/20250915SETPLgAmp_and_AttenuationModel.zip
DOI 10.12197/2025GA026
Source
Language Eng
Relation
Coverage
Rights China Earthquake Networks Center (CENC), National Earthquake Data Center, Incorporated Research Institutions for Seismology Data Management Center (IRIS), and the Institute of Geology and Geophysics, Chinese Academy of Sciences.