# Teleseismic Tomography for Imaging the Upper Mantle Beneth Northeast China
## 3 Northeast China
### Inversion Resolution and Reliability Evaluation
#### 3.3.3 Inversion Results  
The results of this study are presented in horizontal and vertical sections below. The horizontal slices are divided into 12 representative horizontal slices at 60 km intervals, as shown in Figure 9.  
On the 60 km depth profile, there is a large range of high-velocity anomaly in the Songliao basin, but there is an independent low-velocity anomaly in the north side. The separation track of high-velocity and low-velocity at the west side of the Songliao basin is consistent with the location of the gravity cascade belt in the Great Khingan Mountains. The Changbai volcano group shows a high low-velocity anomaly as a whole, but there is an obvious high-velocity anomaly on the southeast side of North Korea. The distribution of velocity disturbance on the 120 km depth profile is basically the same as that of the 60 km depth profile. The range of low-velocity anomaly on the southwest side of the Songliao basin is slightly reduced, and the low-velocity anomaly on the north side still exists independently. At the depth of 120 km, the high-velocity and low-velocity separation tracks in the 60 km depth profile are still distributed along the Greater Khingan Mountains gravity cascade belt. On the 180 km depth profile, the low-velocity anomaly in the north of the Songliao basin seems to be connected with the low-velocity anomaly in the west of the Greater Khingan Mountains, which is strengthened on the 240 km depth profile. The 240 km depth profile shows that the discrete low-velocity anomaly distribution is more connected with each other. Figure 8: Test results and inversion results of \(0.8^{\circ}\times 0.8^{\circ}\times 50\) km gridOn the 300 km depth profile, the high-velocity anomaly in the Songliao basin is weaker than that in the shallow part. The low-velocity anomaly in the northern part of the Songliao basin forms a ring with the low-velocity body in the Arshan volcano area, and the high-velocity distribution range in the southwest is expanded. The low-velocity distribution area corresponding to the Changbai volcano group, several small volcanoes included, is larger, showing the homology of these volcanoes in the upper mantle. On the 360 km depth profile, it can be seen that the low-velocity disturbance degree and distribution range in the south are reduced, Jingpohu Volcano and the Changbaishan volcano group  
Figure 9: Horizontal section of P-wave velocity disturbance in the upper mantle of the study area (60–360 km). are connected into a piece at this depth, and the small-scale high-velocity anomaly disappears in the west side of the middle of these volcanoes at the depth of 300 km. On the depth profiles of 420 km and 480 km, as shown in Figure 10, it can be seen that with the deepening of the depth, the low-velocity abnormal disturbance under the volcano increases, and the low-velocity abnormal disturbance under the Arshan and on the side of the Songliao basin gradually separates. On the 560 km depth profile, it can be seen that the low-velocity anomalies under the west side of the Changbaihan volcano group increase sharply in the disturbance degree and distribution range, and the low-velocity anomalies on the east side also increase in the disturbance degree. This shows that there is a large range of low-velocity anomaly in the mantle transition zone under Changbai Mountain, suggesting the possible source of thermal material in the upper mantle. On the 620 km and 680 km depth profiles, the low-velocity anomalies in the mantle transition zone below the west side of Changbai Mountain are more obvious, and continue to expand along the east-west direction. There are obvious low-velocity anomalies under the east side of the Five-linked-great-pool Lake (FLGPL) volcano group. The velocity disturbance is lower than Changbai Mountain, but the range is larger. In the 740 km depth profile, the distribution of low-velocity anomalies is more discrete than in the mantle transition zone, which may indicate that the upper low-velocity anomalies come from the deeper mantle.