Using traditional algorithms to identify persistent scatterer (PS) points is challenging during bridge construction because of short-term changes at construction sites, such as earthworks, as well as the erection and dismantling of temporary structures. To address this issue, this study proposes a PS point selection method based on statistical theory and Gaussian Mixture Model-Expectation Maximization (GMM-EM) algorithm. This method adopts amplitude information as an incoherence evaluation indicator. Furthermore, the statistical median of the amplitude dispersion index and amplitude mean is screened twice to extract a set of candidate points, including PS points that exhibit stable backscattering over long durations. Temporal coherence is simultaneously used as the coherence evaluation indicator. Another candidate point set is obtained by extracting high-coherence PS points using the GMM-EM algorithm. These sets of candidate points are then combined to obtain a final PS points set. In the experiment, the deformation monitoring of the under-construction Shenzhen-Zhongshan Cross-Sea Bridge in China was selected as a case study, with 28 Sentinel-1A images used as the data source for PS selection and deformation information extraction. The results show that the proposed method enhanced the density and quality of PS points on the under-construction cross-sea bridge compared to existing PS selection methods, thus offering higher reliability. Deformation analysis further revealed fluctuating deformation trends at characteristic points of the Shenzhen-Zhongshan Cross-Sea Bridge, indicating the occurrence of elastic deformation during its construction.

The air temperature changes in the Palu MW7.5 earthquake in Indonesia on 28 September 2018 were analyzed, based on the additive tectonic stress caused by celestial tidal-generating forces (ATSCTF) and air temperature data from the National Center for Environmental Prediction (NCEP). This paper explored the variation characteristics of three-dimensional stratified of air temperature caused by seismic activity and the coupling relationship between air temperature changes and the tidal force. The background information for air temperature calculation was obtained from the tidal force changes, and the air temperature increment method was used to study the temperature evolution process of different periods in the study area. The results found that the tidal force acting on the critical state earthquake faults may be an important external factor inducing earthquakes, and there was indeed a significant air temperature increase anomaly during the Palu MW7.5 earthquake. The paper also summarized the abnormal characteristics of air temperature caused by seismic activity: the air temperature closer to the land’s surface has greater anomaly amplitude and a wider anomaly area than that of the upper air.

This study examines the three-dimensional layered air temperature variations associated with the Hualian M6.9 earthquake, which occurred on 18 September 2022, using data from the National Center for Environmental Prediction (NCEP) and extracting background information for air temperature through tidal forces. Changes in air temperature stratification revealed that near the epicenter, temperature anomalies began on 12 September and peaked on 13 September, with pronounced increases in magnitude and area. These anomalies followed a seismic thermal anomaly pattern, i.e., one with greater amplitude and a wider range near the land surface, decreasing with altitude until they dissipated, while the other exhibited high atmospheric temperature anomalies, i.e., the upper atmospheric warming exceeded that near the land surface, likely due to meteorological factors. Stable weather conditions and a low geomagnetic Kp index and Dst index during the research period supported the reliability of these findings. The deformation field recorded by InSAR reflects crustal deformation directly caused by fault slip and stress accumulation; moreover, the area with significantly higher air temperature coincides with the areas with the most concentrated deformation.

The Kamchatka Peninsula is one of the most seismically active regions in the world and experienced the Mw 8.8 earthquake in 2025. To examine whether tectonic processes were associated with enhanced atmospheric warming while minimizing external interference, this study analyzed multi-level air temperature fields from the NCEP (National Centers for Environmental Prediction) reanalysis data. A tidal-force-based background framework was used to characterize the vertical evolution of air temperature excesses before and after the mainshock. Results showed that a pronounced warming excess emerged near the epicentral area prior to the earthquake. The warming excess exhibited the strongest intensity and amplitude in the near-surface layer and decayed progressively with altitude, a pattern that may be consistent with the vertical attenuation expected for tectonically related thermal excesses. Sentinel-5P SO₂ observations showed enhanced volcanic SO₂ concentrations from mid-July 2025, before the Mw 8.8 mainshock. The SO₂ enhancement was observed in the volcanic regions of the study area, suggesting that the SO₂ signal may reflect enhanced regional degassing activity while also being influenced by volcanic emissions, plume dispersion, and atmospheric transport. Sentinel-1A InSAR observations derived from SAR images acquired on 23 July and 4 August 2025 represent cumulative coseismic line-of-sight (LOS) deformation associated with the Mw 8.8 mainshock, rather than preseismic subsidence. Overall, the air temperature excesses and SO₂ enhancement may provide auxiliary evidence for possible changes in the regional volcanic-tectonic system before the earthquake, whereas the InSAR result provides coseismic deformation context. These findings highlight the potential value of vertical air temperature structure for investigating possible earthquake-related thermal signals, but further studies based on multi-year statistical analyses of various observational datasets and additional earthquake cases are still required.

The Hualien M6.9 earthquake on September 18, 2022 was calculated based on the additional tectonic stress caused by celestial tidal-generating forces (ATSCTF) model. The period of celestial tidal-generating forces was the time background of the air temperature calculation, and the air temperature variation of three-dimensional layered before and after the Hualien earthquake was studied combined with the air temperature data from the National Center for Environmental Prediction (NCEP) of United States. According to the changes of ATSCTF, the Hualien earthquake occurred within the Period B among the three periods: Period A, Period B, and Period C. The air temperature stratification changes during these three periods were calculated separately, and the results showed that on September 12 in Period B, a temperature increase phenomenon began to occur near the epicenter of the Hualien earthquake. On September 13, the air temperature increase anomaly was significant, and the amplitude and area of the temperature enhancement anomaly increased. On September 14th and 15th, the anomaly gradually weakened and disappeared, and the change of the air temperature anomaly followed the seismic thermal anomaly law caused by tectonic movement: the air temperature closer to the land’s surface had a greater anomaly amplitude and a wider anomaly range; as the altitude increases, the air temperature gradually decreases, and the range of anomalies gradually reduces until it disappears. Meanwhile, there were also high temperature anomalies on September 4 and 5 in the Period A, as well as October 1 to October 4 in the Period C. However, the amplitude and area of the warming anomalies in the upper atmosphere were larger than those near the land surface, which did not conform to the seismic thermal anomaly law caused by tectonic movements and did not belong to the seismic thermal anomalies. In addition, the solar geomagnetic KP index in the study area was relatively low during Period B, indicating that it was in a calm period of solar geomagnetic.