## 1 Introduction
A similar case was investigated by [26], wherein they evaluated the effects on the array response caused by topographic variations (i.e., deviations from the datum) within receiver arrays. They found that these variations had more negative effects on the array response than position errors because of their relatively high error amount in most environments. In addition, topographic variations directly affect the vertically traveling signals as opposed to position errors, which mainly affect noise. Finally, topographic variations leave very little human control to reduce their amount, whereas position errors can be reduced using more accurate instruments and measurement procedures. Ref. [27] studied the performance of an array in the presence of lateral near-surface heterogeneities. They used a model with two adjacent layers to study the array performance as a function of the number of affected elements and the velocity ratio between the two adjacent layers. They found that the array performance decreased with the number of affected elements and amount of deviation of the velocity ratio from unity. Ref. [28] studied the change in the wavelet response of seismic receiver arrays in the presence of a dipping near-surface layer. They used a model with different dip and incidence angles as well as various types of signal and noise incident on the array. Their results show that incidence and dip angles have opposite effects on the array response. Refs. [29, 30] studied the array response in the presence of laterally varying thickness of the weathering layer. They generated several models and calculated their corresponding array responses in the ideal and perturbed cases. They found that horizontally traveling waves were less affected than vertically traveling waves in all studied models and errors. Ref. [31] studied the seismic array response in the presence of variations in elements' elevations, positions, and weights using a zero-phase Ricker wavelet. They found that topography had the largest effects on the array response and that different error types did not combine linearly. Almost all previous studies have addressed the effects of non-ideal array conditions using analytical (or numerical) modeling approaches without testing their approaches on field data. The problem with field data studies is the difficulty in measuring the exact position and elevation of all receivers. In this paper, we summarize, modify, and update equations required for correcting non-ideal array conditions; then, we study the array response in the presence of topographic variations (i.e., elevation errors) and positioning errors within the array using field data from a shallow seismic survey acquired in eastern Saudi Arabia. We quantify the elevation and position errors (relative to a datum and nominal geophone spacing, respectively) at every geophone location using their Differential Global Positioning System (D-GPS) coordinates. Furthermore, we quantify enhancements in the array response using the stacked energy of first arrivals in each error case normalized by its corresponding error-free case. This paper starts with the calculation of the velocities of the direct and refraction events in the presence of elevation and position errors. Next, the elevation and position errors are calculated using the survey geometry information. This is followed by calculation of the array response in terms of its trace energy after elevation error removal, position error removal, and removal of both errors. We finally compare them with the trace response of the ideal case (i.e., after removing both elevation and position errors).