Evaluation of near-surface deposit stiffness and site characterization through seismic refraction tomography in diriyah urban development area, Saudi Arabia

1. Introduction

Seismic refraction (SR) is an effective method for outlining shallow subsurface structures, determining bedrock depth and geotechnical parameters, and detecting fractures. This technique plays a critical role in constructing accurate geological models by offering comprehensive coverage of the study area. Many researchers have employed seismic refraction to examine bedrock and subsurface structures for engineering purposes. (Redpath, 1973; Dutta, 1984; Bennett, 1999; Palmer, 2001; Rucker, 2000; Sirles et al., 2006; Alhassan et al., 2010; and Adeoti et al., 2013). Seismic refraction tomography presents a sophisticated alternative to traditional layered refraction methods. It is especially effective when conventional techniques struggle, such as in areas with significant lateral or vertical velocity variations. Due to its ability to handle strong lateral velocity gradients, refraction tomography is ideally suited for complex geological environments.

Diriyah is located on the northwestern outskirts of Riyadh and holds historical significance as the original home of the Saudi royal family. It served as the capital of the Emirate of Diriyah during the first Saudi Dynasty (1744–1818). The remnants of the old city, primarily comprised of mud-brick structures, are found along both sides of Wadi Hanifa, which extends southward through Riyadh and beyond. Rapid urban development is occurring due to the increasing demand for residential, educational, and industrial infrastructure. However, some structures are constructed on brittle limestone with varying topography, which may pose structural risks, particularly during heavy rain and rainfall.

Some geological and geophysical studies have been carried out near the study area to determine the depth of the engineering bedrock and evaluate the geotechnical characteristics of soil deposits (Abdelrahman et al., 2017; Abdelrahman et al., 2023; Abdelrahman et al., 2024a&b, and Qaysi et al.,2025). Furthermore, recent advancements in soil mechanics encourage a more sustainable approach to land use and construction (Akbar and Al-Tabbaa, 2020; Yuan and Han, 2022; Sharma and Singh, 2023). Mapping near-surface geotechnical parameters is crucial for evaluating soil suitability for urban and sustainable construction, as well as examining their potential impact on the stability and safety of future structures. It is essential to analyze soil stiffness, engineering properties, and its capacity to endure the stresses and loads associated with construction activities. A comprehensive understanding of the soil’s strength, stability, and response to pressure is vital for ensuring the structural integrity of buildings and infrastructure planned for the area.

Diriyah, located on the northwestern outskirts of Riyadh, holds profound historical and strategic significance as the original home of the Saudi royal family and the former capital of the First Saudi State. It is undergoing rapid urban expansion as part of national development initiatives aimed at diversifying infrastructure and promoting heritage tourism. However, this growth intersects with complex geological conditions, including brittle limestone formations, variable topography, and susceptibility to weathering factors that can compromise structural stability if not adequately assessed. As such, understanding the subsurface characteristics of Diriyah is crucial for ensuring safe construction and foundation design, while preserving the region’s cultural heritage and supporting sustainable urban development. This study area presents a unique intersection of geological complexity, urban pressure, and historical value, making it an ideal candidate for advanced geotechnical investigations.

This study aims to integrate seismic refraction and seismic refraction tomography methods in Diriyah’s new urban expansion zone (Fig. 1a) to assess soil stiffness and geotechnical properties and their implications for the area’s sustainable development. The findings will enhance soil stabilization strategies, urban planning, and resource conservation while aligning with global sustainability objectives.

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Fig. 1.

(a) A map indicating the location of the study area and the seismic refraction tomography profiles contained within it, (b) A geologic map of the study area.

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This study presents a comprehensive geophysical and geotechnical characterization of the near-surface deposits in the rapidly developing Diriyah Urban Development Area, employing an integrated approach that combines seismic refraction and refraction tomography. Unlike previous studies that focused primarily on either qualitative subsurface mapping or limited geotechnical parameters, this research provides high-resolution 2D tomographic models that identify three distinct geological layers and quantitatively derives critical engineering parameters, including shear modulus, bulk modulus, Poisson’s ratio, and bearing capacity. The spatial analysis of these parameters offers actionable insights into soil competence and construction suitability, directly supporting sustainable land-use decisions. Moreover, the classification of soil stiffness based on NEHRP standards within a historic and urbanizing area establishes a practical framework for resilient urban development, making the study methodologically and contextually novel.

2. Geological setting

Geologically, the study area is part of the Jubaila Formation from the Upper Jurassic Period (Steineke and Bramkamp, 1952; Vaslet et al., 1991; Fig. 1b), which is exposed northwest of Riyadh and covers a vast region. The Jubaila limestone, with a thickness of 116 meters, is divided into upper and lower units east and west of Wadi Hanifa (Manivit et al., 1985). The Lower Jubaila Formation on the eastern side forms a 20–30-meter-high cliff, where talus deposits of sand and silt accumulate. This talus extends beyond the shoulder and covers the lower unit, which likely consists of interbedded layers of micrite and calcarenite, each ranging in thickness from 10 to 20 cm (Vaslet et al., 1991). Above this interbedded sequence lies a 0.5-meter-thick, silicified, fine-grained limestone layer that is uniform and extends over a large area. Directly above this layer, the upper section of the lower unit contains limestone caves varying in size from a few centimeters to several meters (Vaslet et al., 1991). In contrast, the upper unit of the Jubaila Formation is 60 meters thick, lacks distinct layering, and is composed of intraclastic and bioclastic calcarenite.

A drainage network has developed along joints and fracture zones, extending west to east across the limestone outcrop. The region is characterized by broad, steep-sided valleys, some of which exceed 100 meters in depth, shaped by erosion. These valleys are partially filled with coarse-grained alluvial deposits up to 50 meters thick. The deep sedimentary layers of the Jubaila Formation act as an aquifer, classified as a moderate water reservoir in terms of quantity and quality (Alzahrani et al., 2020). Near the study area, most subsurface layers retain water due to secondary porosity. Faults and fractures are crucial in recharging these aquifers by channeling surface runoff and Wadi flows, enhancing surface water availability.

3. Materials and Methods

Seismic refraction (SR) is a reliable technique for assessing subsurface properties, including depth and horizontal extent, by analyzing estimated P-wave velocities within the studied profile. Additionally, refraction data can significantly enhance other exploration methods, including drilling, test pits, and geological mapping. While P-wave velocities do not directly indicate rock type, they provide valuable information about overlying soils, fracturing, and weathering within rock formations. The penetration depth depends on the surface profile length, which includes geophones and source points, as well as the anticipated subsurface velocities. Generally, the maximum penetration depth is estimated by dividing the total spread length by three (Moony, 1980; Anderson, 2006; Wightman et al., 2004). Therefore, seismic velocity analysis helps identify subsurface lithology, distinguishing different rock units such as soil, weathered, or compacted rock layers (Venkateswara et al., 2004). The shear wave velocity can be derived from the primary wave velocity using the following equation:

Seismic refraction tomography (SRT), waves also known as velocity gradient or diving-wave tomography, relies on the first arrival travel time of seismic waves as input (Zhu and McMechan, 1989; Stefani, 1995). This method represents the subsurface as a continuous medium, where the recorded first arrival times are independent of any high-velocity contrast within the medium or refractor. It effectively illustrates the velocity gradient with depth in the surveyed area. SRT employs a generalized simulated annealing algorithm that repeatedly performs forward modeling and conditionally accepts new models based on a probability criterion. This approach helps the algorithm avoid non-unique, local travel-time minima, ensuring the development of a unique, globally optimized model of the subsurface velocity structure. Unlike traditional methods, SRT does not assume a specific orientation for the subsurface velocity gradient, allowing it to detect vertical structures and significant lateral velocity variations. SRT is particularly well-suited for areas with strong lateral velocity contrasts, rugged topography, or complex near-surface structures, especially when little to no prior information about the subsurface is available (Optim, 2001).

Seismic refraction tomography (SRT) is widely used in geotechnical investigations to map subsurface structures and evaluate their suitability for construction and other engineering applications (Rucker, 2000; Raghu and Iyengar, 2007; Chiemeke, 2014). SRT generates a cross-sectional image along the survey profile by analyzing how soil responds to energy from an external source, such as a hammer impact. As the energy propagates through the subsurface, the collected data helps visualize variations in material properties along the profile (Fkirin et al., 2016; Hayashi and Takahashi, 2001; Safety IS, 2004). Geotechnical parameters (Table 1) define the key physical and mechanical properties of the soil, which are essential for assessing its behavior in engineering applications. These parameters include foundations, retaining walls, dams, and tunnels. They help engineers evaluate the different strengths, stabilities, compressibilities, and overall performances of materials under various loading conditions.

4. Data acquisition

Seismic refraction surveys and tomography were conducted across the study area along nine distinct profiles, each measuring 115 meters in length, as shown in Fig. 1. A 24-channel seismograph system was used for data acquisition. The seismic refraction method involved several key components: a seismograph to record seismic signals, a 12V DC battery for power, a trigger cable to synchronize the seismic source with the recording system, two seismic cable reels with signal cables connecting the geophones, 10 kg sledgehammer as the energy source, a metal base plate to ensure consistent energy transmission, and 24 geophones with a frequency of 4.5 Hz to detect refracted seismic waves.

During field operations, the 24 geophones were evenly spaced along the survey line and connected to the seismic cable reels, which were then linked to the seismograph for data collection. The seismic energy was generated by striking the metal base plate with a 10 kg sledgehammer, an effective method in low-noise environments. Each seismic refraction profile utilized five shot points: two offset shots placed beyond the profile ends, a forward shot near the beginning of the line, a midpoint shot at the center, and a reverse shot near the end.

In seismic refraction tomography, shot points were placed at each geophone location, resulting in 24 shots per profile. This setup ensured comprehensive seismic data collection, capturing wave propagation over various distances and providing a detailed view of the subsurface structure. Each shot point underwent multiple recordings with stacking processes to enhance the signal-to-noise (S/N) ratio. This technique involved repeatedly activating the seismic source and averaging the results to reduce random noise and improve signal clarity.

The high-quality data obtained through this process enabled the accurate interpretation of seismic wave travel times and refraction patterns, allowing for the identification of subsurface geological layers, their depths, and material properties. These insights were crucial for detailed geophysical analysis. To minimize noise interference, data collection was conducted during quiet hours, between 12:00 AM and 6:00 AM on weekends, when traffic was at a minimum. Additionally, geophones were embedded in the soil and buried to further reduce external noise.

5. Data analysis

The seismic refraction data collected in the field were processed and analyzed using SeisImager software (Geometrics Corporation) in combination with the Pickwin and Plotrefa programs. Pickwin plays a crucial role in the initial stages of data processing by identifying and marking the first seismic arrivals, commonly referred to as first breaks. These first breaks, representing the earliest energy waves traveling through the subsurface, are critical for further analysis and stored for subsequent processing. Plotrefa then refines the data by further editing the identified first arrivals and assigning geological layers based on seismic wave velocities. Additionally, it facilitates the calculation of P-wave velocities, which are essential for evaluating subsurface material properties. This is accomplished using advanced techniques, such as inverse modeling, where the subsurface model is adjusted to match the observed data, and iterative ray tracing, which enhances model accuracy by mapping seismic wave paths (Figs. 2 and 3, respectively, for seismic refraction and seismic refraction tomography). Together, these software tools enable detailed processing and interpretation of seismic refraction data, precisely characterizing the subsurface. This comprehensive analysis provides valuable insights into the depth, composition, and physical properties of the underlying geological layers (Table 2).

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Fig. 2.

Sequence for processing seismic refraction data.

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Fig. 3.

Seismic refraction tomography data processing sequence.

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6. Results and Discussion

The generated 2D ground models reveal three distinct subsurface layers. The uppermost layer has a P-wave velocity between 600 and 1800 m/s (Fig. 4a) and an S-wave velocity ranging from 352 to 1058 m/s (Fig. 4b). This broad velocity range suggests the presence of stiff alluvial deposits and limestone rock, with thicknesses varying from 7.5 m to 14.9 m in the southern section of the study area (Fig. 4c). The second layer features P-wave velocities between 2500 and 4700 m/s and S-wave velocities ranging from 1470 to 2764 m/s. Composed of weathered limestone, this layer is thicker, spanning from 15 m to over 30 m in the eastern region. These velocity values indicate a more compacted material, often associated with fractured limestone rock. The fractures indicate that the rock is not completely intact but has undergone weathering, resulting in a transition zone between the loose surface deposits and the more solid rock below. The third and deepest layer is characterized by higher velocities, with P-wave values ranging from 4,000 to 5,000 m/s and S-wave velocities ranging from 2,352 to 2,941 m/s. This notable increase in velocity at greater depths marks the transition to a more consolidated and rigid rock mass. This layer consists of massive limestone, serving as the area’s engineering bedrock, with varying depths. The bedrock surface exhibits irregular topography and generally slopes in both eastward and westward directions, likely due to the influence of faulting or weathering. On average, this third layer is about 15 m deep in the eastern region, progressively increasing to more than 30 m toward the east and southwest.

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Fig. 4.

(a) Distribution of P-wave velocity within the study area, (b) Variations in soil thickness across the study area, (c) Distribution of S-wave velocity throughout the study area.

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The distribution of Poisson’s ratio, shown in Fig. 5(a), ranged from 0.179 to 0.237. This ratio exhibited a consistent upward trend in the southwestern part of the study area, while a relative decline was observed in the northeastern zone. These variations indicate differences in the soil’s mechanical behavior, reflecting how it responds to stress and strain under different loading conditions (Johnson and Williams, 2020).

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Fig. 5.

(a) Variation of Poisson"s ratio in the study area, (b) Variation of the material index in the study area, (c) Variation of the concentration index on contour lines in the study area, (d) Variation of the stress ratio on contour lines in the study area.

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The material index is a vital geotechnical parameter for evaluating and classifying soils and rocks based on their physical and mechanical properties. It helps understand how these materials respond to different environmental and loading conditions, providing insights into their stability, strength, and suitability for construction (Davis and Zhang, 2020). In this study, material index values range from 0.049 to 0.282. Fig. 5(b) illustrates that the contour map significantly increases material index values in the northeastern region. This rise suggests that the soil in this area exhibits more favorable characteristics for construction and load-bearing applications. Higher material index values indicate a stronger and more stable material with increased resistance to deformation and improved structural load support (Kim et al., 2021). The observed increase in the wadi likely reflects variations in subsurface composition, enhancing the area’s suitability for engineering applications such as foundation design and slope stability analysis.

The concentration index is a crucial geotechnical parameter for evaluating the distribution and concentration of specific materials within soils and rocks, including minerals and particles. It provides valuable insights into the spatial variations in the physical and chemical properties of subsurface materials, which affect geotechnical behavior, including compaction, permeability, and strength (Zhang and Liu, 2020). In this study, concentration index values range from 5.208 to 6.571. As depicted in Fig. 5(c), the contour map reveals a notable increase in these values toward the valley in the southwestern region. This rise suggests a higher concentration of specific materials in that area, indicating improved soil composition. Higher concentration index values imply enhanced soil stability, strength, load-bearing capacity, and drainage properties, making the southwestern region more favorable for construction and development (Davis and Zhang, 2021).

The stress ratio is a key parameter that describes the relationship between different stress components within the soil. Understanding this ratio is crucial for evaluating soil behavior, designing foundations, constructing retaining structures, and assessing slope stability, as it influences the soil’s response to applied loads and susceptibility to shear failure (Terzaghi and Peck, 2017). In this study, stress ratio values range from 0.218 to 0.311. Fig. 5(d) shows that the contour map highlights a notable increase in stress ratio values in the southwestern region.

The density parameter is a key geotechnical indicator used to evaluate and distinguish the physical properties of soil. It provides valuable information on compaction, porosity, and moisture content, crucial for determining soil suitability for construction and agricultural applications (Zhao et al., 2019). In this study, soil density within the area varied between 1.64 g/cm³ and 2.02 g/cm³. The analysis revealed a gradual increase in soil density toward the central and southwestern regions, as illustrated in Fig. 6(a). The shear modulus, also known as the modulus of rigidity, is a crucial geotechnical parameter that measures a material’s resistance to deformation under shear stress. It is vital in assessing soil behavior during seismic activities and construction projects. In this study, the shear modulus values range from 1.9 × 10⁹ to 2.3 × 10¹⁰ dyn/cm². As illustrated in Fig. 6(b), the contour map indicates higher shear modulus values in the central part of the study area. This increase suggests that the soil in this region is more rigid and stable, as higher shear modulus values typically correspond to greater resistance to deformation (Wang and Zhao, 2019). The elevated shear modulus reflects the soil’s enhanced capacity to withstand lateral deformation, making it suitable for construction, particularly in areas requiring stable foundations. The increased rigidity in the central zone suggests that the soil can support heavier loads while providing improved stability, reducing the risk of excessive settlement or lateral displacement under shear forces (Lee et al., 2021).

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Fig. 6.

(a) Density distribution in the study area, (b) Variation of shear modulus in the study area, (c) Variation of bulk modulus in the study area, (d) Variation of Young"s modulus in the study area.

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The bulk modulus is a key geotechnical parameter that quantifies a material’s resistance to uniform compression, offering crucial insights into its compressibility and stiffness. It helps evaluate how soil or rock responds under pressure, particularly in engineering and geotechnical applications involving load-bearing conditions (Smith and Lee, 2021). In this study, the bulk modulus values range from 2.98×10⁹ to 3.52×10¹⁰ dyn/cm². As depicted in Fig. 6(c), the contour map highlights a notable increase in bulk modulus values toward the central region of the study area. This rise indicates that the soil in this zone is more rigid and stable, as higher bulk modulus values generally correspond to greater resistance to compression (Jones et al., 2019). The increased bulk modulus suggests that the soil has a higher capacity to withstand compression and deformation. This makes it well-suited for construction projects requiring strong foundational support, especially in areas with high load-bearing requirements (Patel and Wang, 2020).

Young’s modulus is a fundamental geotechnical parameter that measures a material’s stiffness, indicating its response to axial loads or compression. It represents the material’s resistance to deformation under stress, making it essential for assessing soil and rock behavior in geotechnical engineering, particularly in foundation and structural design. In this study, Young’s modulus values range from 4.71 × 10⁹ to 5.59 × 10¹⁰ dyn/cm². Fig. 6(d) shows that the contour map reveals a notable increase in Young’s modulus values toward the central region. This rise suggests that the soil in this area is becoming increasingly stiffer and more resistant to deformation, a crucial factor in determining its suitability for construction and load-bearing applications (Zhang et al., 2019). The elevated Young’s modulus in the valley indicates that the soil can support heavier structures while minimizing the risk of significant settlement or lateral movement under applied loads. This makes it highly suitable for foundational support in construction projects.

The ultimate bearing capacity is a crucial geotechnical parameter representing the maximum load per unit area soil can support before experiencing shear failure. This parameter is crucial in foundation design and structural applications, enabling engineers to assess the soil’s capacity to sustain loads without excessive settlement or failure (Meyerhof, 2018). The ultimate bearing capacity values in this study range from 1.64 to 41.34 kg/cm². Fig. 7(a) shows a notable increase in these values toward the central region. This rise indicates that the soil in this area can support heavier loads, reflecting improved stability and strength due to changes in soil composition, such as increased density or cohesion (Kumar and Patel, 2020). Enhancing soil properties is crucial for ensuring structural stability and optimizing foundation design. This will make the central zone more suitable for construction and load-bearing applications.

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Fig. 7.

(a) Variation of ultimate bearing capacity shown on contour lines in the study area, (b) Site characterization based on Vs of the topmost layer in the study area.

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According to the National Earthquake Hazards Reduction Program (NEHRP, 2004) guidelines, the study area is divided into two classes based on S-wave velocity (Fig. 7(b)), which is crucial for determining construction suitability, as shown in Table 3.

Class C: Soils with S-wave velocities between 360 and 553 m/s are considered very dense soil or soft rocks. Predominantly located in the central zone, they demonstrate high rigidity and low compressibility, offering excellent structural support. Their stability and resistance to seismic wave amplification render them highly suitable for construction.

Class B: Rocks with s-wave velocities from 764 to 1058 m/s cover the central zone. They are categorized as strong rocks with good load-bearing capacity. This site class provides stable foundation conditions, making them more suitable for construction.

Studies such as those by Al-Harbi and Al-Sharhan (2012) and Al-Fawzan and Al-Tamimi (2016) highlight the widespread presence of brittle limestone formations across Riyadh, a characteristic shared with Diriyah. However, Diriyah’s more varied topography, with its hills and valleys, exacerbates weathering and erosion, factors that have been similarly observed in areas like Wadi Hanifah, as discussed by El-Sayed and El-Sherbiny (2015). The growing urban pressures in Riyadh, as described by Al-Dosari and Kadhim (2017), reflect similar challenges in Diriyah, where the rocky terrain compounds the need for safe foundation design. Moreover, Diriyah’s designation as a UNESCO World Heritage site (UNESCO World Heritage Centre, 2010) introduces an additional layer of complexity, with preservation efforts influencing construction strategies differently from those observed in more modern developments in Riyadh. Finally, research into the impact of weathering on geotechnical properties, such as that by Al-Malki (2019), highlights the importance of understanding regional climate factors, which accelerate erosion and affect urban infrastructure and the preservation of cultural heritage in Diriyah. These studies collectively reinforce that while Diriyah shares geological and urban challenges with Riyadh, its unique historical and topographical features demand tailored solutions to balance development with heritage conservation. Additionally, there are studies aimed at assessing site characterization for neighboring areas, such as those by Alzahrani et al. (2022), Qaysi et al. (2025), Almadani et al. (2020, 2021), and Abdelrahman (2025). The findings of this study align with those of other studies in terms of the stiffness and engineering properties of limestone deposits.

7. Conclusions

The study presents ground models of subsurface layers, revealing three distinct strata. The upper layer, composed of stiff alluvial deposits and limestone rock, exhibits a P-wave velocity ranging from 600 to 1800 m/s and an S-wave velocity between 352 and 1058 m/s, with a thickness of 7.5 to 14.9 meters. The second layer, consisting of weathered limestone, exhibits P-wave velocities between 2500 and 4700 m/s and S-wave velocities of 1470 to 2764 m/s, spanning from 15 m to over 30 m. The third layer, comprising massive limestone, features P-wave velocities from 4000 to 5000 m/s and S-wave velocities between 2352 and 2941 m/s, with depths ranging from 15 m to over 30 m. The study also analyzes key geotechnical parameters, with soil density varying from 1.64 to 2.02 g/cm³. Notably, higher values are observed in the central and southwestern regions. Poisson’s ratio ranges from 0.179 to 0.237, with increased values in the southwest area. The shear modulus ranges from 1.9 × 10⁹ to 2.3 × 10¹⁰ dyn/cm², with higher values found in the central region, indicating stiffer soil. Similarly, bulk modulus values ranging from 2.98×10⁹ to 3.52×10¹⁰ dyn/cm² and Young’s modulus values from 4.71×10⁹ to 5.59×10¹⁰ dyn/cm² exhibit higher values in the central area, indicating greater soil stability. The material index ranges from 0.049 to 0.282, indicating stronger soil in the northeastern region. The concentration index ranges from 5.208 to 6.571, with higher values in the southwestern region, indicating an improved soil composition. Stress ratio values between 0.218 and 0.311, along with ultimate bearing capacities ranging from 1.64 to 41.34 kg/cm², are higher in the central region, making it suitable for construction and load-bearing applications.

According to NEHRP guidelines, the study area is classified into two site classes based on S-wave velocity: Class C (360–553 m/s): Very dense soil or soft rock, primarily in the central zone, offering high rigidity, low compressibility, and strong structural support, making it ideal for construction. Class B (764–1058 m/s): Strong rock with excellent load-bearing capacity, providing stable foundation conditions, making it highly suitable for construction.

It is concluded that combining seismic refraction and refraction tomography provides comprehensive subsurface data for designing safe and resilient urban environments. This approach facilitates informed decision-making, ensuring sustainable and adaptable urban development. Additionally, drilling geotechnical boreholes will yield more detailed information on subsurface lithology.

8. Limitations of the used methodologies and future research directions

Although seismic refraction and tomography effectively delineated subsurface conditions, several limitations remain. The methods are depth-limited and may fail to detect low-velocity layers beneath high-velocity strata. Results are also sensitive to lateral heterogeneity, environmental noise, and velocity-based assumptions that can oversimplify complex geotechnical behavior. Key parameters were derived indirectly from seismic velocities, which may not fully capture in-situ soil responses. Additionally, the limited integration of borehole data reduces the reliability of model calibration. Future work should combine these techniques with MASW, resistivity imaging, and direct sampling to achieve a more comprehensive site characterization.

To build upon the current findings, future research should integrate additional geophysical techniques such as MASW and ERT to enhance near-surface resolution, particularly in heterogeneous zones. Incorporating borehole data, including SPT and CPT results, will improve model calibration and parameter accuracy. Developing 3D subsurface models will enable better visualization of lateral variability and geological structures. Seasonal monitoring can reveal the effects of moisture and environmental changes on soil behavior. Site-specific seismic hazard assessments should be conducted to evaluate amplification risks and inform the development of design codes. Additionally, integrating geotechnical data into GIS-based planning tools will support sustainable land use, while validating predictions through real-world monitoring at construction sites will enhance the reliability of subsurface assessments.