The landforms and deformations are described and mutually compared based on their size, height, and slope (dip). Nonetheless, the respective indices can be more accurately compared using quantitative measurements. The following indices were incorporated in this study:

This index represents the equilibrium between the erosive forces causing mountain front irregularities and the effective tectonic forces which form the mountain front’s straight line [4] and is defined as below (Figure 1):

To evaluate S_mf, the mountain front in Burkh Anticline was divided into 6 sections. The respective sections are enumerated from west to east (Figure 2) and their corresponding information is included in Table 1.

Therefore, the mountain fronts influenced by active uplifiting are nearly straight and their S_mf indices roughly equal 1. But, if the uplifting intensity decreases or becomes zero, erosion process starts to form the sinusoidal mountain front which turns more irregular by the course of time.

Active mountain fronts exhibit S_mf values larger than 1.4 [5] . Less active mountain fronts in which tectonic activity is still present suggest S_mf values in the range of 1.4 to 3, and the values exceeding 3 belong to inactive faults. As seen in Table 1, S_mf has its lowest values in sections 2, 3, 5, and 6 (S_mf < 1.4) indicating activity of the aforementioned sections whereas the respective index ranges between 1.4 and 3 in sections 1 and 4 demonstrating less activity compared to other parts of the anticline. However, their activity cannot be completely ignored.

The percentage of mountain front faceting or F% is defined as the ratio of summation of facet lengths in a mountain front (L_f) to the corresponding straight line (L_s) [6] . (Figure 3)

In general, large percentages for this index reflect high level of erosional activity in the mountain front [7] . To measure the F% index, Burkh mountain front was again divided into 6 sections, enumerated from west to east (Figure 4). F% values are included in Table 2.

The most active sections of this region lie in the middle part of the anticline based on the calculations i.e. the lowest faceting extent has been caused by streams in these sections. Yet, northwestern and southeastern sections have smaller values of F% and assume lower relative uplifting activity according to the respective index. These results are to a great extent in accordance with mountain front sinuosity index results.

This index is derived from the following equation:

where, SL is the length of steam trajectory and VL is the length of straight route.

Generally, sinuosity of a waterway increases with increasing slope. This sinuosity variation in turn shows the change and increase of tectonic activity rate. Unity value of this index signifies straightness of stream channel. Values between 1 and 1.5 suggest S-shape stream channel and those exceeding 1.5 represent meandering patterns.

As observed in Table 3, steams 8, 10, 11, and 13 which flow in the middle part of Brukh Anticline are more active than other parts of the anticline. Thus, tectonic forces have influenced along the route of these streams leading to larger uplifts compared to other streams. Morphological Indices of Valley Cross Section.

These indices include ratio of valley floor width to its height (V_f) and valley ratio index (V).

Bull [4] considered the ratio of valley floor width to the average height of valley walls as a scale for the excavation strength of valley and defined V_f index accordingly:

In the equation above, V_f is the width of valley floor, E_1d and E_2d respectively represent the heights of left and right walls of the valley, and E_ac is the elevation of valley floor from sea level (Figure 5).

To determine V_f index, 17 streams were chosen along Burkh Anticline and their cross sectional areas were analyzed. The respective streams are enumerated from west to east. Table 4 presents V_f values calculated for the valleys in the region. According to the values acquired for the valleys in the region, it can be inferred that the tectonic activities are not equal in different parts of the region, and, highly active and lowly active parts can be considered. Based on Table 4, it is seen that small values of V_f index belong to middle part of Burkh Anticline, suggesting further activity of this part compared to other parts.

One of the factors affecting morphology of the stream valley is the erosional mechanism of its walls. This index equals the ratio of valley area to the area of the semi-circle with an equivalent radius of valley depth and is derived from the following formula: V = Av/Ac, where Av is the area of the generated valley and Ac is the area of the semi-circle.

According to Table 5, the minimum value of V ratio belongs to the central parts and also the southeastern end of Burkh Anticline. V values smaller than 1 indicate greater activity of the valleys.