An Integrated Historical and Instrumental Earthquake Catalog for Sudan

The limited availability of integrated earthquake data represents a critical constraint on seismic hazard studies in Sudan. This paper presents the Sudan Integrated Earthquake Catalog (SIEC) v1.0, a comprehensive, quality-controlled dataset spanning 827 AD to 2023, compiled through the systematic integration of historical and instrumental records from multiple international and regional seismological databases. The historical catalog encompasses 43 events (827–1897 AD) compiled hierarchically from three regional archives. The instrumental catalog integrates data from five prioritized sources. Where, it includes ISC-GEM, ISC Bulletin, USGS, and two regional catalogs. All magnitudes were subsequently homogenized to moment magnitude (Mw) using empirically derived Orthogonal Distance Regression conversion equations. Three established declustering algorithms (Gardner–Knopoff, 1974; Uhrhammer, 1986; Grünthal, 2009) were applied, retaining 23.6–30.7% of events as independent mainshocks. Completeness analysis identifies magnitude-dependent thresholds ranging from 1919 (Mw ≥6.0) to 1982 (Mw ≥3.5). The final unified catalog contains 5,775 events (Mw 2.88–7.2), including the 1990 Juba earthquake (Mw 7.2). This openly available, fully documented dataset provides a fundamental resource for seismic hazard assessment, seismotectonic modeling, and regional geodynamic investigations in Sudan and northeastern Africa.