We present techniques to reduce noise and enhance seismic quality, making possible the first multi-attribute analysis of a 3D seismic volume in the Llanos Foothills (La Florida anticline) of Colombia using coherency and ant-tracking techniques for fault and fracture detection. The results could help reduce risk in models of reservoir fracture porosity and permeability. The dominant fracture strike direction in the studied seismic volume (La Florida anticline) is NE–SW (055 ± 20°), parallel to the structural strike of the adjacent Eastern Cordillera Foothills. The application of the ant-tracking technique also reveals the NE-SW fracture set for the reservoir rocks in the La Florida anticline as well as in the non-folded reservoir rocks to the SE. We compared the fracture intensity and orientation in folded rocks with the fracture intensity and orientation in non-folded rocks. Our study showed NE-SW, NW-SE, and E-W fracture orientations in the non-folded seismic volume, suggesting that regional stresses could produce these fracture sets, not just folding processes as previously proposed. The NW-SE and WNW-ESE fracture sets are only found in the Guayabo Formation (11 Ma–Present). A right–lateral strike–slip displacement on the nearby Algeciras fault system in the last 2 m.y. may have generated WNW-ESE and NW-SE Riedel-type shear fractures in the study area.

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Tabuk city is located within the Red Sea and Gulf of Aqaba active tectonic environment where it has experienced considerable earthquakes in the historical and instrumental period. Recently, Tabuk city is expected to become one of the future economic communities in Saudi Arabia. Accordingly, assessment of seismic hazard of Tabuk city plays an important role to minimize earthquake damage and to anticipate the future safe development for the strategic projects. For this purposes, earthquake data were collected from local and regional data centers to construct earthquake catalogue. The earthquake source zones that affect Tabuk city, maximum magnitude and closest distance have been identified. The stochastic approach has been applied through this study for seismic hazard assessment in terms of peak ground acceleration and the response spectra. The results illustrated that, the maximum peak ground acceleration resulted from Tabuk source zone with moment magnitude (M w) of 7.5. The calculated peak ground acceleration of 218 cm/sec 2 at distance of 10 Km for Tabuk City at the bedrock. The response spectra of Pseudo-Spectral Acceleration (PSA) have been calculated at 5% of the critical damping with a value of 470 cm/sec 2 at 10 Km distance. The results of the present study are highly recommended to improve Saudi Building Code (SBC) for earthquake resistant design in Tabuk city.

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