Taking the 2017 M_w6.5 Jiuzhaigou earthquake as a case study, ionospheric disturbances (i.e., total electron content and TEC) and thermal infrared (TIR) anomalies were simultaneously investigated. The characteristics of the temperature of brightness blackbody (TBB), medium-wave infrared brightness (MIB), and outgoing longwave radiation (OLR) were extracted and compared with the characteristics of ionospheric TEC. We observed different relationships among the three types of TIR radiation according to seismic or aseismic conditions. A wide range of positive TEC anomalies occurred southern to the epicenter. The area to the south of the Huarong mountain fracture, which contained the maximum TEC anomaly amplitudes, overlapped one of the regions with notable TIR anomalies. We observed three stages of increasing TIR radiation, with ionospheric TEC anomalies appearing after each stage, for the first time. There was also high spatial correspondence between both TIR and TEC anomalies and the regional geological structure. Together with the time series data, these results suggest that TEC anomaly genesis might be related to increasing TIR.

Airgun has been used as an active source to generate seismic waves in on‐land reservoirs by releasing high pressure air beneath the water surface. There are significant differences in signal energy and frequency given different airgun placement depths. In this article, we compared and analyzed the signal characteristics of airgun placed at different depths in the Qilian Mountain in Gansu Province. Results show that both the amplitude (energy) and the dominant frequency of the airgun signal increased with increasing placement depths. Within the tested depth range, we found that the optimum airgun placement depth was 30 m and the dominant frequency was 3–13 Hz. Further implementation of these findings can help improve the extraction accuracy of the weak signals in the observation system.

Seismically active northern Tibetan Plateau necessitates the application of remote sensing-driven earthquake precursor detection. We applied wavelet transform and power spectrum analysis to outgoing longwave radiation (OLR) from 37 M ≥ 5.0 earthquakes (2009–2024; 89°–105°E, 31°–43°N), establishing a magnitude prediction model. The results show that: (1) Frequency band 6 demonstrates optimal retrospective detection performance for M5.0–7.0 earthquakes, whereas Band 3 captures anomalies associated with M ≥ 7.0 events; (2) Anomaly area and maximum ratio quantify energy release in M5.0–6.0 earthquakes, while maximum anomaly ratio estimates magnitudes of M6.0-7.0 events; (3) The Qilian Mountains and Bayan Har Mountains exhibit high seismicity due to arid surface conditions, whereas the Qaidam Basin shows elevated OLR power spectrum detection rates attributed to its rigid substrate. Seasonally, summer’s warmer temperatures and atmospheric stability result in OLR anomalies accounting for 34.4% of observations, while winter snow cover induces signal attenuation; (4) Normal faults achieve 100% detection via efficient shallow heat transfer from tensile ruptures, contrasting with a 20% missed detection rate in low-dip reverse faults. The proposed split-band multi-parameter remote sensing prediction framework advances medium-to-strong earthquake risk assessment on the Tibetan Plateau, validating thermal infrared remote sensing’s unique capability in precursor identification.

We observed high-quality waves from a repeatable airgun seismic source recorded by a linear ultra-dense seismic array across the Xiliushui fault zone, one of the inactive faults in the Qilian Mountain, on the northeastern margin of the Tibetan Plateau, China. We used Snell’s law of seismic ray propagation to determine a simplified ambient velocity model. Based on the flexible and precise spectral element method, we computed broadband synthetic seismograms for a shallow low-velocity fault zone (FZ) to model the direct P-wave travel time delay and incident angle of the wavefield near the FZ. The FZ extent range and boundaries were inverted by apparent travel time delays and amplification patterns across the fault. According to prior information on the properties of the direct P-waves, we could constrain the inverse modeling and conduct a grid search for the fault parameters. The velocity reduction between the FZ and host rock, along with the dip angle of the FZ, were also constrained by the P-wave travel time delay systematic analysis and incoming angle of the P-waves. We found that the Xiliushui fault has a 70~80 m-wide low-velocity fault damage zone in which the P-wave velocity is reduced to ~40% with respect to the host rock. The fault damage zone dips ~35°southwest and extends to ~165 m in depth. The repeatability and environment protection characteristics of the airgun seismic survey and the economic benefits of a limited number of instruments setting are prominent.