# Teleseismic Tomography for Imaging the Upper Mantle Beneth Northeast China
## 3 Northeast China  
### Data Information  
In order to cover Northeast China as much as possible, in this paper we select 286 stations, as shown in Figure 2. These stations cover most areas of Northeast China, including the whole Songliao basin. The interval of longitude and latitude between stations is close to 0.8\({}^{\circ}\) with even distribution. The stations are from six arrays, which are represented by different colors. The station details are shown in Figure 3.  
1. The North East China Extended Seismic Array, represented by blue dots, is jointly deployed by China, the United States, and Japan, covering most areas of 42-48\({}^{\circ}\) N and 116-134\({}^{\circ}\) E, with 127 stations in total. The observation time is from June 2009 to December 2011. In this study, 352 teleseismic events during this period were selected.  
2. The XI array represented by purple dots was set up around Changbai Mountain by [PERSON]'s team with 19 stations in total. The observation time was from June 1998 to December 1999. In total, 124 teleseismic events were selected in this study.  
3. The 1U array represented by green dots is densely distributed on the North Korean side of Changbai Mountain, the border between China and North Korea, with six stations in total, and the observation time is from August 2013 to October 2015. In total, 287 teleseismic events were selected in this study.  
Figure 3: Time distribution of array recording.  
Figure 2: Station map and geological background selected in this paper.  
4. The ZX array in the North China Interior Structure Project, represented by pink dots, is densely distributed along the north-south direction, with 47 stations in total. The observation time is from July 2003 to October 2004. In this study, 124 teleseismic events were selected.  
5. The XG array represented by light blue dots, some of which are scattered in the border areas of northeast, North China, and the Great Khingan Mountains, and the others are densely distributed in southern Liaoning with 27 stations in total. The observation time is from November 2002 to December 2008. In this study, 333 teleseismic events were selected.  
6. The 1A array in the NISP plan represented by the orange dots has 60 stations in total, and the observation time is from September 2007 to September 2008. In this study, 200 teleseismic events were selected.  
Firstly, we need to select the waveform data of seismic events, and then take the coordinates (44\({}^{\circ}\) N, 124\({}^{\circ}\) E) as the center to screen the seismic data received by the above six series of the array, and three methods should be followed in the process of screening.  
1. Magnitude/Ms \(\geq\) 5.5;  
2. Epicenter distance is more than 30\({}^{\circ}\) and less than 90\({}^{\circ}\);  
3. Each seismic event requires at least half of the stations to receive signals.  
After the appropriate 1151 teleseismic events are delineated, the vertical component waveform data of the first 100 s and the second 200 s of the first P-wave are intercepted and bandpass filtering is performed on these data. Then, the waveform correlation method is used to pick up the relative travel time residuals. For each event, the two results are relatively consistent, and the relative travel time residuals are obtained. The teleseismic distribution received by the above six arrays can be shown in Figure 4. The distribution of teleseismic events used in this study is reasonable. There is also a good location relationship between the teleseismic event and the station. There are enough rays in all directions except the Arctic.  
Figure 4: Distribution of teleseismic events selected by different arrays: (**a**) 1A; (**b**) 1U; (**c**) XG; (**d**) XI; (**e**) ZX; (**f**) NE.