# Reconstruction of Land and Marine Features by Seismic and Surface Geomorphology Techniques
## 3 Seismic Attributes  
A seismic attribute is any measure (quantitatively) of seismic data that helps interpreters to visually enhance or quantify features and geomorphologies of interpretive interest [88; 89; 90; 91; 92; 93; 94; 95] (Figure 1). The development of seismic attributes has been integrated with seismic reflection interpretation and has roots extending back to the 1930s when geophysicists started to interpret (pick) travel-times with coherent reflections on recorded seismic field data [95]. The development of seismic technology has always preceded the development of seismic attributes that could be a powerful tool in delineating geomorphological features, identifying prospective hydrocarbon volumes, etc. Hundreds of seismic attributes are in existence today, and this number will increase over time. Several seismic attributes duplicate one another, while others are obscure, unstable, or unreliable; other seismic attributes are purely mathematical quantities or are not truly attributes [89; 95; 96; 97]. Many authors have different classifications of seismic attributes; for example, [PERSON] [93] divided the attributes into the following two general categories: geometrical attributes and physical attributes. The purpose of geometrical attributes is to enhance the visibility of the geometrical characteristics or reflection characteristics of the seismic data such as  
Figure 1: Seismic attributes (Root-Mean-Square Amplitude) showing geomorphology of the paleo-seabed reef features. Source: courtesy of Virtual Seismic Atlas (VSA), 2015 (www.seismicdas.org, accessed on 1 January 2015). (VSA author: [PERSON]). seismic reflection configuration (including seismic facies), the reflection intensity of seismic events, dip, azimuth, and continuity. These geometrical attributes have the main function of enhancing seismic interpretation of sequence stratigraphy, seismic stratigraphy, fault, and structural interpretation. On the other hand, the physical attributes pertain to the physical parameters of the subsurface, and, therefore, relate to lithology and pore fluids (reservoir characterization). These include instantaneous phase, correlation coefficient, instantaneous frequency, (attributes derived from analytical seismic traces), interval velocity, amplitude versus offset, and normal moveout (attributes derived from pre-stack data). [PERSON] [90] classified seismic attributes using a tree structure in which time, amplitude, frequency, and attenuation were the main branches that further branched out into post-stack and pre-stack categories with horizon and window mediums. Time attributes are very useful on providing faults and structural geological information; these include residual, dip azimuth and magnitude, curvature, edge, illumination, coherence, semblance, covariance, trace difference, etc. Amplitude attributes work very well on enhancing stratigraphic interpretation and reservoir information, including amplitude versus offset, reflection amplitude, relative impedance, reflection strength, amplitude ratio, root-mean-square (RMS) amplitude, average energy, variance of amplitude, maximum amplitude, etc. Frequency attributes are very useful for identifying and extracting reservoir information (e.g., sandstone reservoir with gas); these include instantaneous frequency, time derivative frequency, spectral decomposition, arc length, dominant frequency, etc. Lastly, attenuation attributes could help us in identifying and extracting other reservoir information (e.g., permeability information); these include instantaneous Q factor, slope instantaneous frequency, slope spectral frequency, etc. [PERSON] et al. [98] introduced a general seismic attribute that was developed following a singularity analysis of migrated seismic data and wavelet transform decomposition.