Wuri Handayani, Irfan Pratama, Nugroho Budi Wibowo

Subduction and Local Fault Earthquake Analysis Using ST-DBSCAN Clustering Algorithm in The Special Region of Yogyakarta (DIY)

Introduction

Subduction and local fault earthquake analysis using st-dbscan clustering algorithm in the special region of yogyakarta (diy). Analyze subduction and local fault earthquakes in Yogyakarta (DIY) using ST-DBSCAN clustering. Study spatio-temporal patterns from 5,403 events (2019-2024) to improve hazard assessment & early warning.

Abstract

This study aims to analyze the spatio-temporal patterns of subduction and local fault earthquakes in the Special Region of Yogyakarta using the ST-DBSCAN (Spatio-Temporal Density-Based Spatial Clustering of Applications with Noise) algorithm. A total of 5,403 earthquake events from 2019 to 2024 were clustered using spatial parameters (2–5 km) and a temporal window of 10 days. The results were evaluated using the Davies-Bouldin Index (DBI) and Silhouette Score. In the subduction zone, nine clusters were identified with a DBI of 3.23 and a Silhouette Score of 0.18, indicating moderate separation. Meanwhile, 25 clusters were detected in the local fault zone, particularly around the Opak and Oyo Faults, with a higher DBI of 3.82 and a negative Silhouette Score (-0.14), suggesting overlapping clusters and weak structure. The clustering outcomes correlate with geological features and offer insights for improving earthquake hazard assessment and early warning systems in Yogyakarta.

Review

This study presents a timely and relevant application of spatio-temporal clustering to earthquake analysis in the tectonically active Special Region of Yogyakarta. The use of the ST-DBSCAN algorithm to process a substantial dataset of 5,403 earthquake events from 2019-2024 is commendable, offering a modern approach to discerning patterns in complex seismic activity. The overarching goal of the research, to improve earthquake hazard assessment and early warning systems, highlights its significant practical implications for a vulnerable region. The clarity in defining the two primary seismic sources – subduction and local faults – sets a clear framework for the analysis. The methodology employed, specifically the application of ST-DBSCAN with defined spatial (2–5 km) and temporal (10 days) parameters, provides a robust framework for identifying seismic clusters. The results for the subduction zone, identifying nine clusters with a Davies-Bouldin Index (DBI) of 3.23 and a Silhouette Score of 0.18, suggest a moderate but interpretable level of cluster separation. More notably, the analysis of local fault zones, particularly around the Opak and Oyo Faults, revealed 25 clusters, albeit with a higher DBI (3.82) and a negative Silhouette Score (-0.14). This latter finding, indicating overlapping clusters and weak structure, is particularly intriguing. While it might suggest limitations in the clustering performance for these specific regions, it could also genuinely reflect the diffuse or complex nature of local fault seismicity, which warrants deeper discussion within the full paper. The reported correlation of clustering outcomes with geological features adds significant credibility to the findings. While the study makes a valuable contribution, further discussion in the full manuscript could enhance its impact. Given the negative Silhouette Score for the local fault clusters, it would be beneficial to elaborate on potential reasons for this outcome – whether it points to the inherent complexity of local fault seismicity, the need for sensitivity analysis regarding the ST-DBSCAN parameters (e.g., varying spatial/temporal windows), or the exploration of alternative clustering approaches for these specific conditions. A deeper dive into the implications of "weak structure" for hazard assessment in these zones would also strengthen the practical recommendations. Overall, this paper offers significant insights into the spatio-temporal dynamics of earthquakes in Yogyakarta and lays a strong foundation for future seismic hazard mitigation efforts, meriting thorough review.

Full Text

Comments

You need to be logged in to post a comment.