# A Fully Automatic DEXP Method for Gravity Data and Its Application on a Potash Salt Deposit
## 5 Conclusions  
We have proposed an improved DEXP method to address the problems associated with automatic calculation and undulating terrain. This method is based on a new definition that incorporates the adding constant method and hypothetical observed surface method. Using the tests conducted on the synthetic model, we demonstrated the flexibility and stability of this approach. Furthermore, we apply the improved DEXP method to real relative gravity data from potash salt deposits in the Sakhon Nakhon basin, Laos. The results of the application validate the effectiveness of this method in prospecting for potash salt deposits.  
It is considered good practice to test the improved DEXP method on synthetic models. When the observed surface is flat, the inverted results of this improved DEXP method demonstrate satisfactory performance. The inverted locations and depths align well with the theoretical parameters, and importantly, the presence of disturbance from the \"zero line\" is effectively avoided, enhancing the reliability of the results. When the observed surface is undulating, the results obtained using a single model exhibit high flexibility, indicating the effectiveness and reliability of the improved DEXP method. In the case of combined models, the results still provide effective indicators, although the reliability varies depending on the intensity of different anomalies. It should be noted that as the undulation of the observed surface becomes more pronounced, the stability of the method decreases to some extent.  
Next, it is important to highlight that the improved DEXP method was applied to real gravity data, and the results align well with the known borehole information, achieving an acceptable level of accuracy. This demonstrates the capability of the improved DEXP method to serve as a valuable tool for automated and reliable estimation of source depth and location. Additionally, by combining the edge detection method, we presented compelling evidence supporting the use of gravity data for effective potash deposit prospecting. This geophysical characterization based on gravity data further emphasizes the potential of gravity data as a valuable component in the prospecting process.  
Clearly, the improved DEXP method demonstrates satisfactory validity and reliability for both synthetic data and real data. Notably, it eliminates the need for manual intervention in setting the SI or threshold value, ensuring stability in the imaging results by avoiding singularities or trapezoid lines. Moreover, it enables direct application to undulating terrain data, which enhances its practicality. However, it is worth mentioning that the accuracy of the method may be compromised when dealing with strongly undulating terrains. Despite this limitation, the proposed method remains significant and valuable for primary imaging of the target objects. It holds the potential to make a substantial contribution to the construction of detailed models for further geological research.  
Conceptualization, methodology, software, formal analysis, and writing: M.X.; gravity investigation: Y.W.; document editing: Y.Y. All authors have read and agreed to the published version of this manuscript. This research was funded by the National Natural Science Foundation of China (grant numbers: 42104092), the Fundamental Research Funds Program of the Chinese Academy of Geological Sciences (grant numbers: JKYQN202351, JY202101), the China Geological Survey Project (grant numbers: GC20230111) and the China Scholarship Council (grant numbers: 202008575035).  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data are not available.  
**Acknowledgments:** This data-acquired work was carried out by Jilin University. Please allow us to show great appreciation to the editor and reviewer for their helpful comments and suggestions.  
**Conflicts of Interest:** The authors declare no conflict of interest.