Fault Movement and Uplift Mechanism of Mt. Gongga, Sichuan Province, Constrained by Co-Seismic Deformation Fields from GNSS Observations

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors investigate the uplift mechanisms of Mt. Gongga through a combination of numerical modeling and seismological analysis. The topic is of broad interest to the geoscience community, and the results are potentially significant. However, the quality of the presentation and the structure of the manuscript require substantial improvement for clarity and coherence. I recommend that the manuscript be considered for acceptance after major revision.

1. The current introduction comprises three long paragraphs that intermingle the regional tectonic background, previous research, and the study’s research motivation. To improve clarity and focus, I suggest either shortening the introduction or restructuring it to clearly separate the tectonic background from the research objectives and literature review. This will help readers more easily grasp the study’s significance and context.
2. Line 326–327:This appears to be a typographical or editing error. Please double-check and revise accordingly.
3. Figure 8:I recommend including the modeled coseismic deformation alongside the observed deformation. Since the authors use these data to constrain their model, a direct comparison would strengthen the validity of the modeling results and improve the overall clarity of the figure.
4. Lines 375–391:The detailed description of the observed GNSS vectors seems somewhat out of place in this section. If the authors consider this content essential, I suggest relocating it to Section 3.1, where it would be more contextually appropriate.
5. Lines 413–431:The methodology for producing the maximum displacement cloud map is unclear. I recommend providing a clearer explanation of how this map was generated. Additionally, the interpretations in this section are difficult to follow—please clarify how the presented models support your conclusions.
6. Figure 12:Please include a proper citation for the fault slip model used in this figure. Additionally, the caption should be expanded to provide more detailed information, including the data source, modeling parameters (if applicable), and a clear explanation of each panel shown. This will help readers interpret the figure more effectively and understand its relevance to the study. Yingfeng ZHANG IGCEA

Author Response

[General Comment]  “The authors investigate the uplift mechanisms of Mt. Gongga through a combination of numerical modeling and seismological analysis. The topic is of broad interest to the geoscience community, and the results are potentially significant. However, the quality of the presentation and the structure of the manuscript require substantial improvement for clarity and coherence. I recommend that the manuscript be considered for acceptance after major revision”.

Response: We appreciate you for your precious time in reviewing our paper and providing valuable and insightful comments that led to possible improvements in current version.

We have carefully considered the comments and tried our best to address every one of them. We have made the necessary professional English revisions to the revised manuscript, and based on your suggestions, optimized the structure of the paper to further improve its quality. We hope the manuscript after careful revisions meet your high standards. Below we provide the point-by-point responses. All modifications in manuscript have been highlighted in blue.

 

[Comment 1]  The current introduction comprises three long paragraphs that intermingle the regional tectonic background, previous research, and the study’s research motivation. To improve clarity and focus, I suggest either shortening the introduction or restructuring it to clearly separate the tectonic background from the research objectives and literature review. This will help readers more easily grasp the study’s significance and context.

Response 1: First, we would like to express our gratitude for your valuable suggestions regarding the introduction. Based on your input, we have made the following improvements to the introduction section: (1). We have shortened the introduction using more concise and clear language. (2). The section has undergone necessary restructuring and modifications. These changes have made the introduction more logically coherent and the language more streamlined, allowing reviewers and readers to better understand the background and significance of the study.

For specific changes, please refer to Section 1 of the revised manuscript. For example, the first paragraph of the introduction has been revised as follows: "The epicenter of the Mw 6.6 Luding earthquake in Sichuan was near Moxi Town, where the southeastern segment of the Xianshuihe fault, a large-scale strike-slip fault, intersects with the reverse and strike-slip the southwestern segment of the Longmenshan fault. The earthquake occurred at the intersection of these two main faults, forming a "Y" shape, precisely beneath the main peak of Mt Gongga, at the foothills of the mountain range (Figure 1). The eastern margin of the Tibetan Plateau in terms of tectonic landforms consists of three primary structural landforms and units: plain (in the eastern Tibetan Plateau), mountain (Mt Gongga), and basin (western Sichuan Basin). They form a typical basin-mountain-plain structure. These landforms and units are products of the Indo-Asia collision, complementing each other in material, spatial interdependence, dynamic transformation, and evolutionary processes [2]. The tectonic activity of the Tibetan Plateau is exceptionally active, making it an ideal window and natural laboratory for studying continental dynamics. The adjacent seismic source area is characterized by the rugged and steep topography of Mt Gongga, which exhibits unique characteristics such as block amalgamation, collisional orogenesis, large-scale strike-slip faults, plateau uplift, and the rise of surrounding orogenic belts [3]. These features provide valuable material for revealing the deep crustal structure and driving forces of the Tibetan Plateau. The exploration of the lateral tectonic effects and deep-seated movement mechanisms in the Tibetan Plateau has been a significant tool in understanding the deformation and evolutionary processes of continental collisions and the orogenic processes of the "basin-mountain-plain" system [4]. The recent seismic event of the Luding Mw 6.6 earthquake in the highest underground mountain range on the eastern edge of the Sichuan-Yunnan Block has captured considerable attention within the geological community.". Please see the revised version. [Pg 3 of 23, Ln 43-67].

Additionally, we have streamlined the literature review in the second paragraph of the introduction. As per your suggestion, we have also separated the literature review from the research objectives. Please see the revised version. [Pg 3 of 23, Ln 71-96].

 

[Comment 2]  Line 326–327: This appears to be a typographical or editing error. Please double-check and revise accordingly.

 Response 2: We deeply respect your diligent and responsible approach to reviewing the manuscript. Thank you for pointing out this minor editing issue. Please see the revised version. [ Pg 10 of 23, Ln 327 ].

For similar minor issues, we have thoroughly reviewed and further refined the revised manuscript.

 

[Comment 3]  Figure 8: I recommend including the modeled coseismic deformation alongside the observed deformation. Since the authors use these data to constrain their model, a direct comparison would strengthen the validity of the modeling results and improve the overall clarity of the figure.

Response 3: We take your constructive suggestion very seriously. After thorough discussion and research within the team, we believe your suggestion is highly professional. By merging the modeled co-seismic deformations with the observed deformation maps, we have indeed made the overall structure of the revised manuscript more optimized and clearer. 

Please see the revised version. [Pg 11 of 23, Ln 369-379].

 

[Comment 4]  Lines 375–391:The detailed description of the observed GNSS vectors seems somewhat out of place in this section. If the authors consider this content essential, I suggest relocating it to Section 3.1, where it would be more contextually appropriate.

 Response 4: Based on your helpful suggestion, we have moved the detailed description of the GNSS vectors from Section 4.1 to Section 3.2 (formerly Section 3.1 in the original manuscript), making the context more coherent and logical.

Please see the revised version. [ Pg 11 of 23, Ln 377-379 ].

The revised content for Section 3.2 of the manuscript is as follows: "Prior to the Luding Mw 6.6 earthquake, the China Earthquake Administration conducted monitoring and analysis, revealing significant interseismic displacement variations between GNSS stations on either side of the Xianshuihe fault (China Earthquake Administration, 2022, Pre-earthquake Deformation Field of the Luding Earthquake) in conjunction with the research findings of Li [43] .Monitoring of the pre-earthquake deformation field data can be found (Figure 7a). Prior to the earthquake, the regional displacement and deformation field generally showed that the southwestern Sichuan-Yunnan block (with displacement and deformation ranging from 10 to 15 mm/yr) had greater southeastward displacement compared to the stable Yangtze block to the east (with displacement and deformation around 5 mm/yr) and the Sichuan-Qinghai block to the north (with displacement and deformation ranging from 5 to 10 mm/yr). The epicenter of the Luding Mw 6.6 earthquake occurred at the boundary where a sudden change in displacement was observed.

Following the Luding Mw 6.6 earthquake, the China Earthquake Administration collected observation data datafrom continuous GNSS stations within the epicentral region (China Earthquake Administration, 2022, Post-earthquake Deformation Field of the Luding Earthquake) in conjunction with the research findings of Guo [44]. Post-earthquake deformation field monitoring and analysis show that to the left of the southeastern segment of the Xianshuihe Fault (Figure 7b). stations near Kangding (SYB1, LS22) in the northern part of the Sichuan-Yunnan block exhibit southeastward vector displacement. To the south of the Sichuan-Yunnan block, stations on the left side of Asbestos (SCJL, LS23, SYD9) show south-southwestward vector displacement. On the right side of the southeastern segment of the Xianshuihe Fault, stations located above Luding in the Sichuan-Qinghai block, such as LS10 and SCTQ near Ya'an, exhibit northeastward vector displacement. At Anshunchang station (SYD5) in Asbestos County, located 50 km southeast of the epicenter, the maximum displacement is 23 mm/yr in the northwest direction. Further south, the station in Asbestos (SCSM) shows a northwest-westward vector displacement of 20 mm/yr, while other vector displacements further from the epicenter are relatively smaller. ".

Please see the revised version. [Pg 9 of 23, Ln 293-322].

 

[Comment 5]  Lines 413–431:The methodology for producing the maximum displacement cloud map is unclear. I recommend providing a clearer explanation of how this map was generated. Additionally, the interpretations in this section are difficult to follow—please clarify how the presented models support your conclusions.

Response 5: In response to your questions and valuable suggestions, we have optimized and improved the generation of the maximum displacement cloud map (Figure 8). We have added the necessary explanations in the extended caption of Figure 8 to help reviewers and readers clearly understand the basic methodology used to generate this figure. The additional explanatory content is as follows: "Note: We constrained the model based on the dynamic and stress field environment of the seismic region, and calibrated the numerical simulation process using GNSS observation data. The finite element contact surface technique introduced in Section 3.1 (Methodology) was employed to invert the planar displacement variation in the Mt Gongga region prior to the earthquake. This approach enhances our understanding of the impact of tectonic stress compression on horizontal surface deformation in the Mt Gongga area."

Please see the revised version. [Pg 12 of 23, Ln 405-412].

 

[Comment 6]  Figure 12:Please include a proper citation for the fault slip model used in this figure. Additionally, the caption should be expanded to provide more detailed information, including the data source, modeling parameters (if applicable), and a clear explanation of each panel shown. This will help readers interpret the figure more effectively and understand its relevance to the study. Yingfeng ZHANG IGCEA

Response 6: Based on your suggestion, we have appropriately included references to the fault slip model in the revised version of Figure 11 (originally Figure 12). Additionally, we have expanded the caption with more detailed and clearer explanations. These modifications aim to help reviewers and readers better understand the relevance of the information presented in the figure. The added explanatory content is as follows: "Note: We constrained the model based on the dynamic and stress field environment of the seismic region, and calibrated the numerical simulation process using GNSS observation data. The finite element contact surface technique introduced in Section 3.1 (Methodology) was employed to invert the planar displacement variation in the Mt Gongga region prior to the earthquake. This approach enhances our understanding of the impact of tectonic stress compression on horizontal surface deformation in the Mt Gongga area."

Please see the revised version. [Pg16 of 23, Ln 519-529].

 

 

Other response explanations for Reviewer 1

In this revised manuscript, in addition to addressing each of the comments and suggestions from the experts, we have further improved the clarity and quality of most of the figures. Additionally, other sections of the manuscript have also been revised and enhanced as necessary.For instance, we have added a broader geological background map (Figure 1) of the study area in the introduction, which will help readers better grasp the significance and context of the research. Please see the revised version. [Pg 2 of 23, Ln 67-70].

We have also optimized the structure of Section 3, "Method and Data," and provided a more detailed analysis in Section 3.1. Please see the revised version. [Pg 9 of 23, Ln 293-322].

Furthermore, we have streamlined the content of the "Conclusions" section. Please see the revised version. [Pg 19 of 23, Ln 665-672] and [Pg 20 of 23, Ln 673-685].

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript under review is devoted to the analysis of an earthquake that occurred in the Sichuan Province of China using Global Navigation Satellite System (GNSS) data. Thus, the content of the paper is generally in line with the Remote Sensing in Geology, Geomorphology and Hydrology section of the Remote Sensing journal. However, in order for the paper to be accepted for publication, the authors are advised to pay attention to the following points.

1. The introduction is too long. It should be shortened. In addition, much attention in the introduction is given to the characterization of the Tibetan Plateau, but it is not clear what is the tectonic relationship between this plateau and Mt Gongga. The text only mentions that Mt Gongga belongs to one of the three structural landforms of the plateau. I recommend that an overview tectonic scheme of the region should be given, indicating the main structural elements.
2. I believe that much of the tectonic information in the introduction can be placed in the Regional Tectonic Background paragraph, which as presented is rather poor in tectonic information. Figure 1 can serve as an overview geologic scheme, but the authors should improve the legend (as presented, it is far from the requirements for geologic map legends).
3. The seismotectonics paragraph needs serious improvement. Seismotectonics is the branch of tectonics that studies the tectonic conditions under which earthquakes occur. The ultimate goal is to predict the location and magnitude of possible earthquakes; in general terms, it is solved by analogy by comparing seismological and tectonic data. None of the above are listed in this paragraph.
4. Satellite Observation Data (GNSS) paragraph contains no data or characterization. The reference to the China Earthquake Administration website is of little use to non-Chinese speakers, which is a big disadvantage for publication in an international journal. By the way, a similar observation can be made in connection with other references to the China Earthquake Administration website.
5. In the Methodology section, the authors mention numerical model and boundary conditions. However, it is not clear what data were used for these purposes and from which data sources. How many data points were used in downsampled coseismic interferograms?
6. The modeling results are presented by a series of interesting figures, performed in good quality. However, I would recommend that the Forward and Inverse Modeling section should be added to the description to justify the presented schemes and cuts. This will allow the reader to evaluate the modeling algorithm and its validity.
7. Conclusion I would recommend reducing to the main conclusions. The first paragraph has nothing to do with the conclusions at all. This information can be omitted as it has already been presented earlier.

In general, we would like to note the high level of the presented work and hope that the authors will not have much difficulty in correcting these shortcomings.

Author Response

[General Comment]  “ The manuscript under review is devoted to the analysis of an earthquake that occurred in the Sichuan Province of China using Global Navigation Satellite System (GNSS) data. Thus, the content of the paper is generally in line with the Remote Sensing in Geology, Geomorphology and Hydrology section of the Remote Sensing journal. However, in order for the paper to be accepted for publication, the authors are advised to pay attention to the following points”.

 “In general, we would like to note the high level of the presented work and hope that the authors will not have much difficulty in correcting these shortcomings”.

Response: First and foremost, we would like to express our sincere gratitude to the reviewer for their recognition and support of our work. We truly appreciate the time and effort you have invested in reviewing our manuscript. Your suggestions are both constructive and professional. Although these suggestions did not pose significant challenges for us, we have taken each of your comments seriously and addressed them with the utmost responsibility.

We have carefully considered the comments and tried our best to address every one of them. We have made the necessary professional English revisions to the revised manuscript, and based on your suggestions, optimized the structure of the paper to further improve its quality. We hope the manuscript after careful revisions meet your high standards and we sincerely hope it will be accepted for publication in Remote Sensing. Below we provide the point-by-point responses. All modifications in manuscript have been highlighted in blue.

 

[Comment 1]  The introduction is too long. It should be shortened. In addition, much attention in the introduction is given to the characterization of the Tibetan Plateau, but it is not clear what is the tectonic relationship between this plateau and Mt Gongga. The text only mentions that Mt Gongga belongs to one of the three structural landforms of the plateau. I recommend that an overview tectonic scheme of the region should be given, indicating the main structural elements.

Response 1: Thank you for your valuable suggestions on the introduction section. In response to your feedback, we have made the following improvements: 

1. We have shortened the introduction by using more concise and clear language. Some of the content from the introduction section has been transferred to the second section of the paper.
2. Necessary reorganization and modifications have been made to the structure of this section. As a result, the logic of the introduction is clearer and the language is more concise.
3. Based on your suggestion, we have added the overall tectonic map (Figure 1) in this section to highlight the tectonic relationship between the eastern edge of the Tibetan Plateau and Gongga Mountain. This shows the main structural elements, helping reviewers and readers better understand the background and significance of the study.

For specific revisions, please refer to Section 1 of the revised manuscript, where the first paragraph of the introduction has been changed to: "The epicenter of the Mw 6.6 Luding earthquake in Sichuan was near Moxi Town, where the southeastern segment of the Xianshuihe fault, a large-scale strike-slip fault, intersects with the reverse and strike-slip the southwestern segment of the Longmenshan fault. The earthquake occurred at the intersection of these two main faults, forming a "Y" shape, precisely beneath the main peak of Mt Gongga, at the foothills of the mountain range (Figure 1). The eastern margin of the Tibetan Plateau in terms of tectonic landforms consists of three primary structural landforms and units: plain (in the eastern Tibetan Plateau), mountain (Mt Gongga), and basin (western Sichuan Basin). They form a typical basin-mountain-plain structure. These landforms and units are products of the Indo-Asia collision, complementing each other in material, spatial interdependence, dynamic transformation, and evolutionary processes [2]. The tectonic activity of the Tibetan Plateau is exceptionally active, making it an ideal window and natural laboratory for studying continental dynamics. The adjacent seismic source area is characterized by the rugged and steep topography of Mt Gongga, which exhibits unique characteristics such as block amalgamation, collisional orogenesis, large-scale strike-slip faults, plateau uplift, and the rise of surrounding orogenic belts [3]. These features provide valuable material for revealing the deep crustal structure and driving forces of the Tibetan Plateau. The exploration of the lateral tectonic effects and deep-seated movement mechanisms in the Tibetan Plateau has been a significant tool in understanding the deformation and evolutionary processes of continental collisions and the orogenic processes of the "basin-mountain-plain" system [4]. The recent seismic event of the Luding Mw 6.6 earthquake in the highest underground mountain range on the eastern edge of the Sichuan-Yunnan Block has captured considerable attention within the geological community.". Please see the revised version. [Pg 3 of 23, Ln 43-67].

The second paragraph of the literature review in the introduction has been simplified, and in accordance with your suggestion, we have separated the literature review from the research objectives.". Please see the revised version. [Pg 3 of 23, Ln 71-96].

Additionally, the added overall tectonic map is shown in Figure 1. Please see the revised version. [Pg 2 of 23, Ln 67-70].

 

 [Comment 2]  I believe that much of the tectonic information in the introduction can be placed in the Regional Tectonic Background paragraph, which as presented is rather poor in tectonic information. Figure 1 can serve as an overview geologic scheme, but the authors should improve the legend (as presented, it is far from the requirements for geologic map legends).

Response 2: In response to your valuable suggestions, we have moved part of the tectonic information from the introduction to the regional tectonic background paragraph. Regarding the concern you raised about the lack of tectonic information, we have added relevant content in this revised manuscript. Additionally, we have modified and improved the legend of Figure 2 (which was Figure 1 in the original manuscript) and incorporated the content from our new Figure 1, the overall tectonic map. We hope that these revisions will meet your approval regarding this issue.

 The changes to this section are as follows: "The research area is located at the complex intersection of multiple tectonic zones, with a stratigraphic lithology of considerable complexity (Figure 2). The main peak mountain group of Mt Gongga exhibits a predominantly SN-oriented belt-like distribution. The main peak group of Mt Gongga consists of Triassic sandstone intermingled with a significant amount of granitic structures, forming a topographically arched mountain. In terms of fault structures, controlled by the southwestern segment of the Longmenshan fault (SW.LMSF), the southeastern segment of the Xianshuihe fault (SE.XSHF), and the Yunongxi fault, exhibits a combination of high-angle strike-slip and thrust faults, oriented from east to west (Figure 3). The southwestern segment of the Longmensh an fault and the southeastern segment of the Xianshuihe fault form an "invertrned-triangle" pattern, while the southeastern segment of the Xianshuihe fault and the Yunongxi fault form a regular "triangle" arrangement within Mt Gongga. From west to east, these blocks are the Sichuan-Yunnan block, the Sichuan-Qinghai block, and the Yangtze block (Figure 1). The main regional faults consist of the southeastern segment of the Xianshuihe fault and the southwestern segment of the Longmenshan fault. The topography of the eastern margin of the Tibetan Plateau exhibits significant variations, with Mt Gongga in the study area reaching an elevation of over seven thousand meters, making it the highest peak in the southwestern Mountain range. At lower elevations, there are modern glaciers, such as the Hailuogou Glacier, which descends to around one thousand meters above sea level (Figure 3). The eastern margin of the Tibetan Plateau, particularly the eastern edge of the Sichuan-Yunnan block, serves as a bottleneck for the escape of material from the plateau and is a core area of left-lateral movement. The southwestern side of the Sichuan-Yunnan block experiences continuous compression and pushing from the Indian Ocean plate, while the northwest side is influenced by the eastward or southeastward overflow of material from the plateau. The eastern side is obstructed by the rigid and cold Yangtze block [33]. The convergence of shallow-level force sources from these three directions, along with the possible upwelling of material from the deep crust beneath the plateau, results in a region with complex geological structures, frequent and intense seismic activity [34]."

Please see the revised version. [Pg 4 of 23, Ln 120-138] and [Pg 5 of 23, Ln 139-152].

 

[Comment 3]  The seismotectonics paragraph needs serious improvement. Seismotectonics is the branch of tectonics that studies the tectonic conditions under which earthquakes occur. The ultimate goal is to predict the location and magnitude of possible earthquakes; in general terms, it is solved by analogy by comparing seismological and tectonic data. None of the above are listed in this paragraph.

Response 3: In light of your constructive suggestions, we recognize the necessity and significance of revising this issue. Therefore, we have made substantial revisions and improvements to Section 2.2 on seismotectonics in the revised manuscript. The modified and added content is as follows: "The southeastern segment of the Xianshuihe Fault (SE.XSHF), the southwestern segment of the Longmenshan Fault (SW.LMSF), and the Anninghe Fault form a typical "Y"-shaped fault structure system along the southeastern edge of the Tibetan Plateau. Notably, the area around Moxi Town in Luding County (on the southeastern segment of the Xianshuihe Fault), which lies at the junction of the "Y" shape, has experienced multiple moderate to strong earthquakes with magnitudes above M6.0 (Figure 4). Historically, this segment has witnessed significant seismic events, including the 1786 Kangding South earthquake (M7.8) and the 1955 Kangding earthquake (M7.5) [4]. The earthquake on September 5, 2022, with a magnitude of M6.6, which occurred at the epicenter near Moxi Town on the southeastern segment of the Xianshuihe Fault, is the latest manifestation of large seismic activity in this region."

"The tectonic system emphasizes the primary active tectonic features in the region and their genetic connections, facilitating a comprehensive and rational analysis of the fundamental pattern and kinematics of regional active tectonics, as well as aiding in the assessment of crustal deformation issues [35]. Since the Quaternary period in the eastern margin of the Tibetan Plateau and the Sichuan-Yunnan region, the crustal activity  during the new tectonic phase has been primarily characterized by horizontal motion with minor vertical movements. The region is characterized by numerous fault zones with significant variations in scale and activity intensity (the Yunongxi fault, Daduhe fault, Hehehaizi fault, and Daliangshan fault exhibit relatively weaker scale and activity intensity; while the Xiaojinhe fault and Anninghe fault exhibit moderate scale and activity intensity). Among them, the southeastern segment of the Xianshuihe fault and the southwestern segment of the Longmenshan fault constitute the main controlling tectonic zone in the region. These faults have fragmented the crust into multiple independent blocks (Figure 4) and govern the overall crustal activity pattern in the area  [36]. The southwestern segment of the Longmenshan fault is a large fault zone comprising a series of imbricate reverse faults. It trends N30°-40° with a northwestward dip, inclined at an angle of 50°-80°. It exhibits clear characteristics of reverse faulting and dextral strike-slip motion. The southeastern segment of the Xianshuihe fault is a major sinistral strike-slip fault zone. This fault trends N150°-160° with a northeastward dip, inclined at an angle of 75°-85°, and exhibits strong ductile shear strain characteristics  [31,37]. The Yunongxi fault is a primarily strike-slip with minor thrusting fault, trending approximately N200° with a northwestward dip [32]. Furthermore, the southwestern segment of the Longmenshan fault is also part of the modern crustal movement along the eastern margin of the Tibetan Plateau, rotating clockwise around the eastern Himalayan structural knot. It forms a composite tectonic zone together with the southeastern segment of the Xianshuihe fault, constituting a typical "Y"-shaped active tectonic system."

"In order to ascertain the geometric structural features of the seismic source associated with the Luding earthquake, which occurred in Sichuan Province, China, the Sichuan Earthquake Administration utilized high signal-to-noise ratio complete waveforms recorded by the regional broadband fixed stations of the seismic network. The Complex Faulting Analysis Procedure (CAP) was employed to calculate the seismic source mechanisms for the mainshock of magnitude Mw 6.6 on September 5, 2022, as well as its aftershocks with magnitudes greater than Mw 3.0. Additionally, Table.1 presents the seismic source mechanism solutions for the Luding Mw 6.6 mainshock derived through far-field waveform inversion by the United States Geological Survey (USGS) and the German Research Centre for Geosciences (GFZ) (Table 1). The corresponding results of the seismic source mechanism inversion released by the Institute of Geophysics, China Earthquake Administration (IGP) can be found at https:∥www.cea-igp.ac.cn/cxdt/279406.html (Institute of Geophysics, China Earthquake Administration). Based on the geometric parameters of the causative fault obtained by USGS, IGP, and GFZ, as well as the spatial distribution of aftershocks and seismic source mechanism solutions, we infer that the southern segment of the Xianshuihe fault exhibits a nearly vertical fault plane with a slight dominant NE dip."

Please see the revised version. [Pg 5 of 23, Ln 154-188] and [Pg 6 of 23, Ln 189-208].

 

[Comment 4]  Satellite Observation Data (GNSS) paragraph contains no data or characterization. The reference to the China Earthquake Administration website is of little use to non-Chinese speakers, which is a big disadvantage for publication in an international journal. By the way, a similar observation can be made in connection with other references to the China Earthquake Administration website.

Response 4: We appreciate the reviewer’s valuable feedback regarding the issues and shortcomings in this section. In response to your suggestions, we have revised and improved Section 3.2, "Satellite Observation Data (GNSS)." Additionally, we have referenced the China Earthquake Administration's website for similar data analysis and observations. Through this study and revision, significant improvements have been made in this section of the manuscript.

 The modifications are as follows: "Prior to the Luding Mw 6.6 earthquake, the China Earthquake Administration conducted monitoring and analysis, revealing significant interseismic displacement variations between GNSS stations on either side of the Xianshuihe fault (China Earthquake Administration, 2022, Pre-earthquake Deformation Field of the Luding Earthquake) in conjunction with the research findings of Li [43] .Monitoring of the pre-earthquake deformation field data can be found (Figure 7a). Prior to the earthquake, the regional displacement and deformation field generally showed that the southwestern Sichuan-Yunnan block (with displacement and deformation ranging from 10 to 15 mm/yr) had greater southeastward displacement compared to the stable Yangtze block to the east (with displacement and deformation around 5 mm/yr) and the Sichuan-Qinghai block to the north (with displacement and deformation ranging from 5 to 10 mm/yr). The epicenter of the Luding Mw 6.6 earthquake occurred at the boundary where a sudden change in displacement was observed."

"Following the Luding Mw 6.6 earthquake, the China Earthquake Administration collected observation data datafrom continuous GNSS stations within the epicentral region (China Earthquake Administration, 2022, Post-earthquake Deformation Field of the Luding Earthquake) in conjunction with the research findings of Guo [44]. Post-earthquake deformation field monitoring and analysis show that to the left of the southeastern segment of the Xianshuihe Fault (Figure 7b). stations near Kangding (SYB1, LS22) in the northern part of the Sichuan-Yunnan block exhibit southeastward vector displacement. To the south of the Sichuan-Yunnan block, stations on the left side of Asbestos (SCJL, LS23, SYD9) show south-southwestward vector displacement. On the right side of the southeastern segment of the Xianshuihe Fault, stations located above Luding in the Sichuan-Qinghai block, such as LS10 and SCTQ near Ya'an, exhibit northeastward vector displacement. At Anshunchang station (SYD5) in Asbestos County, located 50 km southeast of the epicenter, the maximum displacement is 23 mm/yr in the northwest direction. Further south, the station in Asbestos (SCSM) shows a northwest-westward vector displacement of 20 mm/yr, while other vector displacements further from the epicenter are relatively smaller. ".

Please see the revised version. [Pg 9 of 23, Ln 292-320].

 

[Comment 5]  In the Methodology section, the authors mention numerical model and boundary conditions. However, it is not clear what data were used for these purposes and from which data sources. How many data points were used in downsampled coseismic interferograms?

Response 5: We appreciate the reviewer’s concerns regarding this section. In response, we have provided the necessary and concise explanations of the numerical model, boundary conditions, and the data obtained (such as seismic parameters and GNSS observation data). The revisions are as follows: " Based on the seismic parameters of the study area (the tectonic characteristics revealed by the source mechanism analysis of the Luding earthquake and its aftershocks, as shown in Figure 4 and Table 1), along with the stress field and dynamic environment, and incorporating GNSS observation data (regional motion vectors, derived from the China Earthquake Administration’s observations before and after the earthquake), we constrained the model boundary conditions and calibrated the simulation process. We inverted the seismic fault movement characteristics during the main rupture using the Finite Element Interface technique, and analyzed the displacement variations in the Mt Gongga area pre- and post-earthquake. ".

Based on the above explanation, we have provided a detailed step-by-step description in three sections in 3.1 Methodology. Please see the revised version. [Pg 7 of 23, Ln 218-251] and [Pg 8 of 23, Ln 252-283].

Additionally, in Section 3.3 The fitting data used in the study, we have offered a detailed explanation of the source of the fitting data and its fitting relationship with the simulation results. The content is as follows:".  Please see the revised version. [Pg 10 of 23, Ln 323-344].

 

[Comment 6]  The modeling results are presented by a series of interesting figures, performed in good quality. However, I would recommend that the Forward and Inverse Modeling section should be added to the description to justify the presented schemes and cuts. This will allow the reader to evaluate the modeling algorithm and its validity.

Response 6: First of all, we would like to sincerely thank the reviewers for recognizing the quality of our simulation results and the associated figures. In light of your reasonable comments on the figures and the fitting suggestions, we have added detailed explanatory notes to the extended titles of most of the simulation figures, which will help in evaluating the algorithms and effectiveness of the model.

 The following figures have been updated with additional explanations in their extended titles, and for example, the extended title explanation of Figure 8 has been updated as follows: "Figure 8. (a) Pre-earthquake horizontal X-axis displacement simulation map. (b) Isopleth map of maximum displacement in the region. (Note: We constrained the model based on the dynamic and stress field environment of the seismic region, and calibrated the numerical simulation process using GNSS observation data. The finite element contact surface technique introduced in Section 3.1 (Methodology) was employed to invert the planar displacement variation in the Mt Gongga region prior to the earthquake. This approach enhances our understanding of the impact of tectonic stress compression on horizontal surface deformation in the Mt Gongga area.).". Please see the revised version. [Pg 12 of 23, Ln 406-412].

 The extended title explanation of Figure 10 has been updated as follows: "Figure 10. (a: pre-earthquake; b: post-earthquake) Mt Gongga II-II' profile X-axis displacement simulation map. (Note: Based on the finite element contact surface technique used in our numerical simulation, we inverted the variation in X-axis displacement along the Mt Gongga  II-II' profile before and after the Luding earthquake. The aim is to illustrate the lateral compressive tectonic force exerted on Mt Gongga from the west, as the Tibetan Plateau moves eastward, and to analyze the impact of the earthquake on the lateral displacement along the Mt Gongga II-II' profile before and after the event.).". Please see the revised version. [Pg 14 of 23, Ln 485-490].

 The extended title explanation of Figure 11 has been updated as follows: "Figure 11. (a) Distribution map of aftershocks along the fault slip and longitudinal, transvers profiles for the Luding Mw 6.6 earthquake (data from china earthquake administration). (b) Shear displacement simulation map of the Xianshuihe main fault plane during the earthquake. (Note: The left panel of Figure 11a shows the sliding displacement variation along the strike of the southeastern segment of the Xianshuihe Fault during the Luding earthquake. The right panel of Figure 11a represents the spatial distribution of aftershocks in the transverse direction perpendicular to the Xianshuihe Fault. The figure is adapted from Zhang [48]. Based on the numerical simulation of the Luding earthquake, we analyzed the fault slip variation along the Gongga I-I´ fault profile and obtained the fault shear displacement contour map (Figure 11b). This result was then compared and validated with the source fault plane results obtained by the China Earthquake Administration through seismic waveform data (Figure 11a). The shear displacement results from both approaches are consistent, thus supporting the rationality and feasibility of the inversion model used in this study.)". Please see the revised version. [Pg 15 of 23, Ln 517-518] and [Pg 16 of 23, Ln 519-529].

 

[Comment 7]  Conclusion I would recommend reducing to the main conclusions. The first paragraph has nothing to do with the conclusions at all. This information can be omitted as it has already been presented earlier.

Response 7: Based on your suggestion, we have simplified Section 6, "Conclusions," in the revised manuscript. Please see the revised version. [Pg 19 of 23, Ln 665-672] and [Pg 20 of 23, Ln 673-685].

Author Response File: Author Response.pdf