Tower 11 is builtin the western wall of the fortress and looks out over the Banias and the Hula Valley. Two phases of construction are clearly visible. In the first phase, it was a square tower in which each side was 15.5 m long. At that time it was probably a gate tower, perhaps even the main gate to the fortress. Because it overlooks the fosse, it was probably accessible over a bridge. There is an inscription at the top of the outer arch of the tower; visible inside the arch is a groove, along which a portcullis could be raised and lowered.

In the second phase, the tower was enlarged; its new dimensions were 29 by 23 m. At this time it apparently was not used as a gate, although it still provided access to the fortress via a long, steep stairway leading to a postern in the northern wall. During this phase, a large cistern was added to the tower. There is every indication that the tower at this time had at least one additional story: steps climbing from the north lead from inside the fortress to the now destroyed second story, and parts of a spiral staircase can be identified in the debris around the tower. Also found in the debris were the remains of a very large inscription that originally extended over one entire course of stone in the outer wall of the tower

Tower 9 is the southwestern tower of the fortress; here, too, two building phases are discernible. As in tower 11, the first phase was small tower (16 by 14.5 m). To it belong the main hall at the level of the courtyard and the stairway linking the two stories of the tower. Of the second story, only the remains of one wall have survived.

In the second phase, the tower was enlarged; its new dimensions were 26 by 24m. At this time one more level, lower than the previous one, was added; it was accessible via two spiral stairwells.

Tower 7 (17.5 min diameter) forms a semicircular projection from the line of the fortress wall. The part of the tower inside the fortress is rectangular. At its center a large column supports a unique ceiling-a pointed annular vault. Visible in the upper part of the outer wall of the tower are projections that undoubtedly supported machicolations used as outposts to defend the base of the tower. Steps along the wall of the tower, inside the fortress, led to an upper story that has not survived.

Tower 15 was a large tower (26 by 18m). Its surviving sections consist of the story below ground level, which was used as a cistern, as well as a few parts of its first story, which are somewhat reminiscent of Crusader construction. This tower, which stands at the northeastern corner of the fortress and is perhaps the best built and most impressive of all the towers, may have had some ceremonial function. Its interior is divided into six bays, each spanned by a cross vault; two enormous piers rise in the center. Visible in the western wall are the carved springers of the stone arches that originally joined up with the piers.

Towers 3 and 8 served as southern entrances to the fortress. Tower 3 was probably the main gate on the south; after the changes made in tower 11, it became the main gate of the entire fortress.

Here and there along the walls (in tower 16 and in the wall near towers 2 and 12) are small sally ports.

As the water supply to the fortress depended on the accumulation of rainwater, several large cisterns were cut. The largest and most impressive adjoins tower 9. This built cistern (c. 25 by 9 m) was divided into two parts. The northern part is roofed with a barrel vault; Steps along one of its walls give access to the bottom. The southern part is roofed with across vault and is accessible today through an opening in its southern wall, which was breached at some late date. The cistern fed a beautiful small fountain (sabil) near its outer southeastern corner.

Additional cisterns can be found in towers 4, 15, II, in the inner courtyard near tower 10, near tower 2, and in the keep.

The function of the keep, the "fortress within a fortress," was to accommodate the governor or commander of the fortress as his main living quarters and to provide a last refuge in emergencies; this is reflected in its plan. It is protected on three sides by the fortress itself, with a complex independent system of fortifications only on its inner side, facing the fortress courtyard.

The keep is separated from the courtyard by a fosse, which originally was spanned by a wooden drawbridge. A path led over the bridge to an outer gate, where it continued to an inner gate, in the wall of the keep itself, that is now blocked by debris and rubble. At the corners of the keep, facing the fortress courtyard, are two large, solid towers, each with a massive stone glacis. The roofs of these towers control the entire courtyard of the fortress. The outer walls of the keep contained four more towers. The interior of the keep was used for residential purposes.lt consists of a long, narrow hall, measuring 33 by 7 m, flanked by small rooms. A white stucco guilloche is preserved in one of the rooms. Between the inner structure and the two larger western towers a large cistern (16 by 10m) was built, to supply the needs of the keep even during a long siege.

• Fig. 5b - Fault Map from
  Fig. 5b
  
  Location map of the Kalat Nimrod castle on the Golan Heights.
  
  Hinzen et al (2016)
  Hinzen et al (2016)
• Fig. 5c - Geologic Map from
  Fig. 5c
  
  Local geology and faults neighboring Kalat Nimrod after Sneh and Weinberger (2014)
  
  Hinzen et al (2016)
  Hinzen et al (2016)

• Annotated Aerial View of
  Annotated Aerial View of Nimrod Fortress
  
  Used with permission from BibleWalks.com
  Nimrod Fortress from BibleWalks.com
• Nimrod Fortress in Google Earth
  Nimrod Fortress in Google Earth
  
  click on image to explore this site on a new tab in Google Earth
• Nimrod Fortress on govmap.gov.il
  Nimrod Fortress on govmap.gov.il
  
  click on image to explore this site on a new tab in govmap.gov.il

• from Fig. 11 of Hinzen et al (2016) and Plan of Nimrod Fortress of Stern et. al. (2008)

Deformation Map of Gate Tower

from Fig. 11 of Hinzen et al (2016) and Plan of Nimrod Fortress of Stern et. al. (2008)

Figures

A wedge extending from the western base to the eastern top of the tower collapsed and the remains are found at the foot of the hill. However, the eastern elements of the tower survived intact and display interesting deformations, including those in a so-called secret passageway which filled the space between the tower’s western wall and the cliff. At the time when the fortification was damaged by the earthquake, the gate tower had been significantly extended compared with its original size. Hartal (2001) reconstructed the size at the base of the extended tower to 22:5 × 31:8 m and a height of more than 30 m. The extension, when intact, was mantling the former tower on all but the eastern side where the lower part of the tower is leaning against the outcropping bedrock. The passage has a total length of 27 m, is 1.80 m wide and includes an upper and lower staircase with a corridor that connects both. North of the corridor at the start of the lower staircase the passage makes a 55° turn to the east followed by a second turn of 35°, so that 90° are reached in total (Fig. 10). The latter includes two loopholes, and at the upper part of the lower staircase there are two small illumination windows. The west wall and the north wall of the tower served as the passage’s outer walls, whereas the inner walls were built against the bare rock (Hartal, 2001). Both walls and the roofing barrel vault were built from large ashlars, the latter of about 0:6 × 1:2 − 1:6 m. The vault is made of two rows of these large ashlars on each side with a much smaller keystone (bottom width 0.2 m) in the middle.

From an archaeoseismological perspective, this secret passageway is of particular interest and shows an extraordinary damage pattern. The complete row of ashlars east of the keystone moved vertically down by up to 0.25 m along the upper staircase and the corridor (Fig. 10). This deformation continues beyond the corridor around both bends of the passage where it gradually decreases toward the lower end of the passageway at the postern. Figure 10c shows four crosscuts through the laser scan model of the secret passageway. We used the virtual model to measure the resulting block movement (vector sum of horizontal and vertical displacement) at sections separated by 1 m distance (Fig. 10d). The first section was taken immediately at the beginning of the remaining roof of the passageway. The large displacement here of almost 0.20 m is influenced by the missing buttresses, particularly at the western side. From section 2 to 6, which is past the first loophole, the deformation increases steadily from 0.05 to 0.17 m. The following three sections (8– 10), which are in the range of the second loophole, are slightly less deformed. Along the further trend of the corridor, the deformation increases toward its maximum at section 14 with a value of 0.25 m. From there we see an almost linear decrease of the deformation along the second staircase up to section 20 m just in front of the second bend of the passageway. Here, the deformation is down to 0.05 m and it vanishes at section 25. This deformation pattern cannot be evaluated by the proposed scheme from Figure 4. However, the displacements of the voussoir alone result in AGDs of 6.

The uniform drop of the first voussoir east of the keystone along the whole passageway is exactly the same deformation pattern as seen in arches GT1, GT2, and GT3, which are located east of the passage with a cross section parallel to that of the corridor. The displacement of voussoirs here is between 0.17 and 0.37 m. Figure 11 shows a damage scenario which might explain the reason for the existing deformation. The sliding voussoirs indicate a strong westerly directed component of ground motion (arrows not to scale), which disturbed the static equilibrium of the arches. The whole mass of the tower moved westward, probably with increasing amplitudes toward its top. The arches opened and allowed the voussoirs to drop before the back swing of the motion closed the gap. The ground motion also induced some corner expulsion of building material at the northwestern corner of the gate tower, which in turn was responsible for the continuation of the voussoir sliding at the lower staircase. The motion was strong enough to topple the outer section of the gate tower, leaving an almost 45° westdipping slope of the ruin. This rather strong directional motion also explains why Kamai and Hatzor (2007) were able to model the voussoir drop of the arch GT1 (Table 1, Fig. 6) in an east–west directed 2D discrete element model.

• Earthquake Archeological Effects chart
  Earthquake Archeological Effects (EAE)
  
  Rodríguez-Pascua et al (2013: 221-224)
  of Rodríguez-Pascua et al (2013: 221-224)

Effect(s)	Location	Image(s)	Description	Intensity
Dropped Keystones in Arches	East-West Oriented Arches in the Gate Tower and elsewhere Fig. 6 Plan of the Kalat Nimrod castle based on the work of Deschamps (1939) and Hartal (2001). Superimposed on the major structural elements of the fortification are the 95 arches listed in Table 1. The center of each arrow represents the position of an arch, the arrow head points to the right when looking at the arch from the outside, and the arrow length varies with the span of the arch. Labels are those from Table 1. The axis units are in meters, the origin of the local coordinate system was chosen at the southwestern corner of the fortress. Hinzen et al (2016) Fig. 9 On top of the map from Figure 5 the ADGs of all 90 evaluated arches are plotted. The range of values is indicated by the legend. Five zoom windows give an enlarged view of sections with dense arch coverage. At towers with arches A12.x and A8.x higher ADGs are found on the western side of the structures. For the huge tower with the arches A19.x at the northeastern corner of the fortification, the damage at the outer edge of the tower is greater than at the hill side. At the large rectangular tower at the southwestern corner, no pattern in the distribution of the damage degree was found. Hinzen et al (2016)	Nimrod Castle Photo by Jefferson Williams (2018)	General Observations from Hinzen et al. (2016) Figures Figures Fig. 3 Fig. 3 The matrix shows photos of examples of damage to stone arches. Rows correspond to the indicated damage category and columns to the severity of the damage. Hinzen et al (2016) - Arch Damage Matrix (shows photos of damage) from Hinzen et al (2016) Fig. 6 Fig. 6 Plan of the Kalat Nimrod castle based on the work of Deschamps (1939) and Hartal (2001). Superimposed on the major structural elements of the fortification are the 95 arches listed in Table 1. The center of each arrow represents the position of an arch, the arrow head points to the right when looking at the arch from the outside, and the arrow length varies with the span of the arch. Labels are those from Table 1. The axis units are in meters, the origin of the local coordinate system was chosen at the southwestern corner of the fortress. Hinzen et al (2016) - Plan of Nimrod Castle with arch damage locations from Hinzen et al (2016) Fig. 7 Fig. 7 (a) Measured rise of 95 arches of the Kalat Nimrod fortress with respect to the span. The dashed line is a linear regression of the data points with a slope of 0.55. (b) Rose diagram of the orientations of the 95 arches from Table 1 with respect to north; bin size is 15°. Hinzen et al (2016) - Arch Damage Analysis from Hinzen et al (2016) Fig. 8 Fig. 8 Graphs used to evaluate the damage of individual arches of the Kalat Nimrod fortress and results of that evaluation. From left to right (top row) these include a digital photo image (cracks are emphasized by lines, breakouts are hatched) an orthographic view of the front with the main dimensions a crosscut section a longitudinal section Histogram of the frequency of occurrence of ADGs among the 90 evaluated arches of Kalat Nimrod. Bin size is 0.5 ADG degrees Distribution of ADGs with t size (span) of arches Distribution of ADGs with azimuth of the arches’ orientation All graphs are plotted to the same scale. Example is arch A1.2 in Table 1 Hinzen et al (2016) - Arch Damage Analysis from Hinzen et al (2016) Fig. 9 Fig. 9 On top of the map from Figure 5 the ADGs of all 90 evaluated arches are plotted. The range of values is indicated by the legend. Five zoom windows give an enlarged view of sections with dense arch coverage. At towers with arches A12.x and A8.x higher ADGs are found on the western side of the structures. For the huge tower with the arches A19.x at the northeastern corner of the fortification, the damage at the outer edge of the tower is greater than at the hill side. At the large rectangular tower at the southwestern corner, no pattern in the distribution of the damage degree was found. Hinzen et al (2016) - Plan of Nimrod Castle with ADGs from Hinzen et al (2016) Discussion The study concentrated on semicircular arches, a popular feature in Islamic sacral and defense architecture Fig. 7 summarizes arch geometry and orientation Fig. 7a shows that "most arches follows a clear linear relation of 0.55 times the span, indicating that the arch type is circular" Typical Analysis of an individual arch is show in Fig. 8a-d Hinzen et al (2016) examined 95 arches at Nimrod Castle using digital images and 3D laser scans Results for 90 arches are detailed in the Arch Damage Grade (ADG) Assessment Table Results for all arches are shown visually in Figure 7 and Figure 8e-f ADGs ranged from 1-8 with "with a maximum of the distribution between ADGs of 3 to 3.5" (Fig. 8e) "A slight tendency toward increased ADGs with increasing arch span might be deduced from Figure 8f; however, there are not enough wide arches with a span above 4 m to adequately quantify this conclusion." "Figure 8g shows that the original hypothesis of a clear correlation between the azimuthal orientation of an arch and the damage it suffered does not hold. Considering the fact that there are only few arches within the azimuthal ranges from 20° to 50° and 125° to 140° the distribution of ADGs with azimuth appears to be fairly uniform. The spatial distribution of ADGs is plotted on top of the plan of Kalat Nimrod in Figure 9." JW: This might also indicate that more than one earthquake was responsible for the damage. Hinzen et al (2016:11) cautioned that ADGs "should not be equated to site intensities." Hinzen et al (2016:13) noted that their selection of studied arches did not "represent the complete damage scenario" because it did not include "the many totally collapsed arches for which the deformation of the upper part allowed the keystones to drop completely out". Hinzen et al (2016:13) noted that "when the damage grade of all surveyed arches is taken together with respect to the arches’ orientations, no clear pattern can be discerned." Hinzen et al (2016:13) noted that "our original hypothesis was triggered by the obvious difference in deformation between arches GT1, GT2, and GT3 on the one hand and arches GT9 and GT10 on the other. These are located near the entrance of the inner gate in the gate tower, oriented almost exactly at 90° with respect to each other and show severe and almost no movement of voussoirs, respectively. GT9 does show severe spalling at the pillar blocks and voussoirs, also indicating a strong westerly component of ground motion." Hinzen et al (2016:13) noted that "orientation dependent voussoir movement is found throughout the gate tower including the secret passage" Hinzen et al (2016:13) noted that although "in the gate tower the collapse obviously induced the damage of the oriented arches, this is not generally the case throughout the fortress as a whole." Hinzen et al (2016:13) noted that The arch labeled GT1 was the object of a discrete element model by Kamai and Hatzor (2007) to estimate ground-motion parameters that caused the damage. They concluded that a peak acceleration of 1g at a frequency of 2 Hz within the modeled structure is sufficient to explain the deformation. This leads to a horizontal displacement of ∼6 cm at the first-floor level of the tower; possibly at higher levels of the tower the displacement was even greater. These dynamic properties are in agreement with an estimate of the minimum horizontal opening that the arches GT1–3 must have experienced. Measurements from the laser scans indicate that the dislocated voussoirs required an opening of the arch between 4.5 and 5 cm.	VI+
Displaced Masonry Blocks	northwestern tower (aka the Gate Tower)	Nimrod Castle - In the northwestern tower (aka the Gate Tower) Used with permission from BibleWalks.com	From an archaeoseismological perspective, this secret passageway is of particular interest and shows an extraordinary damage pattern. The complete row of ashlars east of the keystone moved vertically down by up to 0.25 m along the upper staircase and the corridor (Fig. 10). ... The uniform drop of the first voussoir east of the keystone along the whole passageway is exactly the same deformation pattern as seen in arches GT1, GT2, and GT3, which are located east of the passage with a cross section parallel to that of the corridor. The displacement of voussoirs here is between 0.17 and 0.37 m. Figure 11 shows a damage scenario which might explain the reason for the existing deformation. The sliding voussoirs indicate a strong westerly directed component of ground motion (arrows not to scale), which disturbed the static equilibrium of the arches. The whole mass of the tower moved westward, probably with increasing amplitudes toward its top. The arches opened and allowed the voussoirs to drop before the back swing of the motion closed the gap. The ground motion also induced some corner expulsion of building material at the northwestern corner of the gate tower, which in turn was responsible for the continuation of the voussoir sliding at the lower staircase. The motion was strong enough to topple the outer section of the gate tower, leaving an almost 45° west-dipping slope of the ruin. This rather strong directional motion also explains why Kamai and Hatzor (2007) were able to model the voussoir drop of the arch GT1 (Table 1, Fig. 6) in an east–west directed 2D discrete element model. - Hinzen et al (2016:9-)	VIII+
Displaced Masonry Blocks		Nimrod Castle Photo by Jefferson Williams (2018)		VIII+
Dipping Broken Corners		Nimrod Castle Photo by Jefferson Williams (2018)		VI+
Collapsed Walls	outer section of the gate tower Fig. 11 Detailed plan of the gate tower (see Fig. 6). The plan shows the main features of the tower at different levels. The large arrows (not to scale) indicate the interpreted ground motion and structural reaction. The plan of the tower follows the work by Hartal (2001). Hinzen et al (2016)	Fig. 2 K Collapsed wall of the northern watchtowers of Kal'at Nimrod lay in disarray at the bottom of a steep slope. The large ashlars fell in 1759 Marco (2008) Nimrod Castle - collapsed wall next to the In the northwestern tower (aka the Gate Tower) Used with permission from BibleWalks.com Nimrod Castle - collapsed wall next to the In the northwestern tower (aka the Gate Tower) Used with permission from BibleWalks.com	toppled "the outer section of the gate tower, leaving an almost 45° west-dipping slope of the ruin." - Hinzen et al (2016:11)	VIII+
Fractured lintels (penetrative fractures?)		Nimrod Castle Photo by Jefferson Williams (2018) Nimrod Castle Photo by Jefferson Williams (2018) Nimrod Castle Photo by Jefferson Williams (2018)		VI+?

Figures

If the wavelength of a seismic wave is approximately equal to the appropriate dimension of the ridge, constructive interference during propagation can lead to a resonance condition where the wave is effectively amplified. Since the ridge effect, according to Massa et al (2010), tends to occur on ridges which are perpendicular (or more properly orthogonal) to incoming seismic energy, the appropriate dimension is the 420 m long axis reported by Hinzen et al (2016:2). This axis will be perpendicular to seismic energy which radiates from the Rachaiya fault which is thought to have ruptured during the 1759 CE Safed Quake. The next parameter to be determined is the shear wave velocity of the underlying bedrock. Kamai and Hatzor (2007) provided some mechanical properties that allows one to estimate shear wave velocity of ~4500 m/s using the calculator below:

Shear Wave Velocity Calculator

• Inputs
  • Shear Modulus 54.2 GPa
  • Density 2604 kg/m³
• Output
  • Shear Wave Velocity 4562 m/s

f = V_S/λ

where

f = frequency (Hz.)
V_S = Shear Wave Velocity (m/s)
λ = Wavelength (m)

Hinzen, K. G., et al. (2016). "Quantifying Earthquake Effects on Ancient Arches, Example: The Kalat Nimrod Fortress, Dead Sea Fault Zone." Seismological Research Letters.

Kamai, R. and Y. Hatzor (2008). "Numerical analysis of block stone displacements in ancient masonry structures: A new method to estimate historic ground motions." International Journal for Numerical and Analytical Methods in Geomechanics 32: 1321-1340.

Robinson, G. (1837). Travels in Palestine and Syria: In Two Volumes. Palestine, Colburn. - open access at archive.org

Rodríguez-Pascua, M. A., et al. (2011). "A comprehensive classification of Earthquake Archaeological Effects (EAE) in archaeoseismology: Application to ancient remains of Roman and Mesoamerican cultures." Quaternary International 242(1): 20-30.

Schultz, W., et al. (2003). "The Al-Subayba (Nimrod) Fortress: Towers 11 and 9." Journal of the American Oriental Society 123: 243.

Deschamps, P. (1939). Les Châteaux des Croisés en Terre Sainte II: La défense du royaume de Jérusalem, Paris Librairie Orientaliste Paul Geuthner

Hartal, M., Amitai, R., & Boas, A. (2001). The Al-Subayba (Nimrod) Fortress: Towers 11 and 9 (Vol. 11). Israel Antiquities Authority. - at JSTOR

Nimrod Fortess at BibleWalks.com

Nimrod Fortress National Park

Nimrod Fortress at Jewish Virtual Library

M. Van Berchem, Journal Asiatique Serie 8/12 (1888), 466ff.

P. Deschamps, La defense du royaume de Jerusalem, Paris 1939, 145-174

W. Muller-Wiener, Castles of the Crusaders, London 1966, 45-46

M. Benvenisti, The Crusaders in the Holy Land, Jerusalem 1976, 147-157

T. S. R. Boase, A History of the Crusades 4 (ed. K. M. Setton), Madison 1977, 140-164

R. Amitai, Dumbarton Oaks Papers 43 (1989), 113-119; E. Ellenblum, ibid., 103-112.

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