Journal of Engineering Geology

Analysis of earth surface elevation changes induced by an earthquake using differential radar interferometry in the Khoy region

Asghar Milan

As one of the key factors causing changes in the Earth's altitude, earthquakes can lead to subsidence or uplift in different areas. These changes are mainly caused by the displacement of tectonic plates, movement along faults and changes in pressure deep within the Earth. The type of fault and the conditions of the earthquake determine whether uplift or subsidence occurs. Monitoring and examining these changes is of great importance for crisis management and relief, improving urban planning, and reducing environmental damage. To study changes in the Earth's surface, various methods are used, including accurate alignment, global positioning systems, laser scanning, and remote sensing, each of which has a specific accuracy and characteristic. Nowadays, satellite data and remote sensing methods are an efficient tool for calculating the vertical displacement of the Earth's surface. This study investigated the potential of Sentinel-1 satellite data and images to study land surface changes due to the 5.6-magnitude Khoy earthquake using the radar differential interferometry technique. Processing the radar images before and after the earthquake allowed us to extract the vertical displacements of the phase changes. The results show uplift and subsidence occurring in some areas close to the epicentre and in more distant places. The maximum uplift was 0.08 metres and the maximum subsidence was -0.156 metres. These results demonstrate the non-uniform pattern of land surface elevation changes caused by this earthquake.

Evaluation of cement performance in stabilizing saline soils from the Urmia lake basin

Mehrdad Emami Tbrizi

Aeolian sands in arid and semi-arid regions are considered problematic due to their loose structure, low bearing capacity and difficulty in compacting them. Iran's dry climate and phenomena such as the desiccation of Lake Urmia have exacerbated the dispersion of saline sands. One common approach to mitigating these issues is chemical stabilization using additives such as cement. This study investigates the effect of stabilizing saline aeolian sands collected from the Lake Urmia basin using Type I Portland cement. Stabilized soil specimens with varying levels of salinity and cement content were prepared and subjected to unconfined compressive strength testing after a 7-day curing period. The results showed that increasing the cement content significantly improves compressive strength. Furthermore, the presence of salt in the soil samples did not hinder the stabilization process, but instead contributed to improved strength in the short term. These findings highlight the importance of considering the type and concentration of salts when designing stabilization treatments for saline granular soils in arid and semi-arid climates.

Numerical analysis and investigation of axial force, shear force and horizontal displacement in underground structures (case study: pataveh-Dehdasht tunnel)

Masoud Khahanipour

This study aims to numerically analyze the axial force, shear force, and horizontal displacement in Tunnel B on the Pataveh-Dehdasht axis. The tunnel is part of a national project that was inaugurated in the summer of 2023. The project's technical specifications include 2.2 million cubic meters of earthwork, 2,100 meters of retaining walls, 110,000 tons of subbase and base layers, and 95,000 tons of asphalt. This study investigated the effect of tunnel lining thickness on shear force, axial force, and horizontal and vertical displacement using PLAXIS finite element software in a two-dimensional framework. Plane strain theory was employed with 15-node elements for modeling. The Mohr-Coulomb constitutive model, one of the fundamental stages in numerical analysis and a common model for tunnel excavation simulations, was applied to model the soil behavior of the study site. The results indicate that increasing the lining thickness reduces vertical and horizontal displacement at all points while increasing axial and shear forces. Maximum deformation occurs at the tunnel invert and minimum deformation occurs at the right sidewall of the tunnel. Increasing the lining thickness from 20 cm to 35 cm leads to a reduction of approximately 100% in tunnel floor settlement and a significant decrease in horizontal displacement exceeding 90% at certain points. These results demonstrate the importance of selecting an appropriate lining thickness for controlling deformations, enhancing load-bearing capacity, and improving the tunnel's seismic safety.

Estimation of transmissivity and hydraulic conductivity of the hashtgerd plain aquifer using step-drawdown test method via Aquifer Win 32 software

younes mousavi

Planning the management and optimized consumption of groundwater resources is a critical infrastructural necessity, as these resources supply a significant portion of the country's drinking water. A key component of this planning is accurately calculating the water balance, which requires determining the aquifer's hydrodynamic parameters, including transmissivity (T) and hydraulic conductivity (K). This study calculated these parameters using step-drawdown pumping test data from a single-well system across various locations in the 411-square-kilometer Hashtgerd Plain aquifer (an unconfined aquifer) with AquiferWin32 software. The results indicate that transmissivity is distributed unevenly across the plain. The lowest transmissivity values were observed in the southern (Kourosh Town) and southwestern (Najmabad) sectors, while the highest values were associated with the Kordan alluvial fan and its downstream lands. Based on these findings, maximum transmissivity was estimated at 3,682 square meters per day, with an average of 440 square meters per day. Hydraulic conductivity was determined by integrating saturated thickness data from geoelectrical studies with the previously calculated transmissivity values. The final results showed that hydraulic conductivity ranges from a minimum of 0.2 meters per day in the southern regions to a maximum of 9.7 meters per day in the central aquifer.

Groundwater sustainability assessment in the Kermanshah aquifer based on indicators and analytic hierarchy process (AHP)

Morteza Mozafari

Groundwater plays a vital role in meeting the drinking and agricultural water needs of Kermanshah Plain. In order to protect the aquifer, it is important to evaluate its sustainability in the face of current and future demands and stresses. Groundwater sustainability indicators help ensure the sustainable management of these resources. This research aims to evaluate the sustainability of groundwater resources in the Kermanshah Plain using various indicators. To this end, AHP analysis was used to evaluate the sustainability indicator of this aquifer based on nine indicators in five quantitative, qualitative, environmental, social, and political sectors. First, the value of each indicator was calculated, and then its sustainability was evaluated using data transferred to GIS software and interpolation. Next, the weight and rank of each indicator and category were calculated to prepare an index-equivalent map. Then, using weighted overlap, the final sustainability map was obtained. Finally, the Receiver Operating Characteristic (ROC) curve was used to measure the accuracy of the results. The prepared sustainability map shows that indicators of groundwater storage changes and quality conditions are among the most important factors affecting the sustainability of the plain's groundwater resources. The results also show that the sustainability situation is weaker in the central areas and more favorable in the border areas (river headwaters) and southeast of the aquifer. To improve the sustainability of the region's groundwater resources, it is recommended that new water management policies be adopted with the participation of the people and based on scientific, principled solutions.

Fractal analysis of seismicity parameters and crustal stress evaluation in eastern Iran

Saeed Zarei

The active tectonics of eastern Iran, resulting from the convergence of the Arabian and Eurasian plates and numerous active faults, has caused high stress concentration, as evidenced by major historical earthquakes such as those in Tabas (1978) and Bam (2003). This study aims to conduct a fractal analysis of seismicity parameters and investigate crustal stress heterogeneity in eastern Iran. To this end, an earthquake dataset of historical and instrumental events with Mw ≥ 4 (1900–2024) was compiled from the ISC and NEIC databases. After filtering and declustering, the data were analyzed using ZMAP and ArcGIS. The b-value (an indicator of stress level and the probability of large earthquakes), the D-value (the geometrical complexity of faulting), and the D/b ratio were calculated simultaneously and mapped spatially. The results show that the b-value ranges from 0.8 to 1.1, and the D-value ranges from approximately 1.6 to 2.3. Regions with low b-values and high D-values, especially along the Nehbandan and Dasht-e Bayaz faults, indicate high stress concentrations and an elevated likelihood of larger earthquakes. The total seismic moment of the cataloged earthquakes is estimated at 3.5×10²³ N·m, yielding an average annual seismic moment rate of 2.7×10¹⁶ N·m/yr (calculated by averaging over the available catalog years). The D/b ratio, regarded as an index of stored energy and stress heterogeneity, exceeds two in these zones and exhibits a strong correlation with areas of a high rate of seismic moment release. This pattern implies that an increase in fault geometrical complexity coupled with a decrease in the b-value signals the crust’s approach to the rupture threshold. Thus, by emphasizing the significance of the D/b ratio, the present findings offer a quantitative approach to mapping stress states, fault structures, and the potential for significant earthquakes in eastern Iran.