Aqaba City Research Articles

Structural Damage from Earthquakes in the Second–Ninth Centuries at the Archaeological Site of Aila in Aqaba, Jordan

The ancient ruins of the city of Aqaba are located at the head of the Gulf of Aqaba along the seismically active Dead Sea Transform fault in southern Jordan. Detailed archaeological excavation and geologic mapping were conducted along an active fault that cuts through Late Roman/Byzantine to Early Islamic deposits at the archaeological site of Aila in Aqaba. In this paper, we describe the stratigraphic evidence for ground-rupturing earthquakes that have affected the site and document the associated collapse, damage, and repair of the architecture in antiquity. These data show that there have been seven earthquakes that have disrupted the archaeological deposits since the second century A.D., based on evidence of faulting. Our data clearly show that historical earthquake catalogs are incomplete with regard to some of the less damaging earthquakes that have affected southern Jordan but may have played a significant role in the cultural history of the region.

Archaeoseismological investigation of the ancient Ayla site in the city of Aqaba, Jordan

Many tens of severe earthquake damage patterns were revealed at the ancient city of Ayla. The seismic deformation patterns are of various types, including systematic tilting of walls, systematic shifting and rotation of wall fragments and individual stones, arch deformations and joints crossing two or more stones. Features of later repair, supporting walls and secondary use of building stones suggest that the damage patterns can be explained by two historical devastating earthquakes: (I) revealed in the constructions built during the late Rashidun period (644–656 A.D.); (II) revealed in the structures restored and/or built during the Fatimid period (1050–1116 A.D.). The maximum observed intensity of both earthquakes at the studied site was not less than IX (EMS98 scale). The sources of the seismic events were probably the Dead Sea Transform and Wadi Araba Faults that cross the site obliquely. The last 1995 Nuweiba earthquake with maximum observed intensity VIII has also left its clear traces in the excavated ancient Ayla buildings. The severity of the destruction was significantly increased because of site effects.

The investigation of metal concentrations in street dust samples in Aqaba city, Jordan

The concentrations of metals (Fe, Zn, Cu, Cr, Pb, Cd, Ni, Mn and Co) in 140 street dust samples were collected from Aqaba city, Jordan. These samples were determined using flame atomic absorption spectrophotometry after digestion with aqua regia. The highest levels of metal concentrations were found in the samples from heavy traffic. While the lowest levels of metal ions were noted in the street dust samples from hospital and health centers and school gardens. The results of this study were compared with several cities around the world. The levels of the metal concentrations found were generally below the mean world-wide values of street dust samples. Metal values in urban street dust samples were several times higher than the control levels. The statistical analyses were applied to the data matrix to determine the analytical results and to identify the possible source of pollution in the studied area. Correlations between the metal concentrations of the street dust samples were obtained. Factor analysis showed that the area was mainly influenced by three sources, namely lithogenic, traffic, and industrial.

Local Site Effects Estimated from Ambient Vibration Measurements at Aqaba City, Jordan

Ambient vibration measurements have been employed to estimate empirical site response functions in Aqaba City, Jordan. These measurements were made, using H/V technique, on nine selected sites that are representative for the different geological units beneath the city. The results show site–dependent variations in spectral amplitude, dominant frequency, and amplification level. The dominant frequency of the alluvial sediments shows a general decreasing in the NW direction from 1.8 to 0.3 Hz. No reliable difference in the levels of amplification that are in the range 1.8 to 2.1 was determined. The measurements at the highly fractured granitic site exhibit amplification of 1.8 at 3.9 Hz. The results indicate that the thickness of the loose sediments in western and northwestern part is much thicker than they are in eastern and northeastern parts. The shallow basement rocks in the eastern and northeastern shoulder of the city have direct effect on the measured peak frequency. The intensity and distribution of seismic destruction of the Gulf of Aqaba earthquake (November 22, 1995, Mw = 7.3) appear to correlate well with the dominant frequency as obtained in this study.

Assessment of radon-222 concentrations in buildings, building materials, water and soil in Jordan

Monitoring of radon gas ( 222Rn) in Jordan was started in the early 1990s. Since then our radon group at Yarmouk University and others have carried out tens of studies that include measurements of indoor radon, radon in water, radon in soil and radon emanating from building materials. All major cities of Jordan had been surveyed, from the northern city of Irbid down to the southern port city of Aqaba. Most of these studies were carried out by using time-integrated passive radon dosimeters containing CR-39 solid-state nuclear track detectors. In addition to that, an active radon monitor was used to study the seasonal variation of 222Rn in Al-Ruseifa that lies near abandoned phosphate mines and in Amman area. During such a study passive dosimeters were also used. The average radon concentrations in dwellings in Jordanian cities ranged from about 20 to 386 Bq/m 3 with the highest readings exhibited during the winter season around the town of Al-Ruseifa.

A GIS-Based Assessment of Liquefaction Potential of the City of Aqaba, Jordan

The city of Aqaba, Jordan, located along the northern shore of the Gulf of Aqaba, is built over the seismically active Dead Sea Transform plate boundary fault system. The subsurface stratigraphic sequence underlying the city is composed of alluvial fan deposits containing varying amounts of clay, silt, sand, and gravel interbedded within the coastal areas with aeolian and beach sand. Groundwater levels along the coastal areas are very shallow. The groundwater levels increase to the north and northeast to depths greater than 17 m about 5 km from the shore. The liquefaction potential of the city of Aqaba soils was analyzed using the Simplified Procedure of Youd and Idriss and the modified Chinese criteria of Wang. Maps of the liquefaction susceptibility of areas in the city of Aqaba were displayed using the Geographic Information System (GIS). Application of the modified Chinese criteria indicates that the cohesive subsurface layers are predominantly nonliquefiable. The types of sediments most susceptible to liquefaction are saturated silt and sand deposits. Two classification schemes were developed in this liquefaction analysis. Our results indicate that the coastal areas of Aqaba have a high potential to liquefy, whereas the eastern parts of the city lie predominantly within a nonliquefaction zone. The critical facilities were overlaid with the liquefaction hazard map of the city and show that only the hotel and the commercial districts lie within a zone of high susceptibility to liquefaction. The areas that have historically experienced liquefaction were found to exist within the high susceptibility zone as well, supporting the findings of this study.

Ground-penetrating radar investigation of active faults along the Dead Sea Transform and implications for seismic hazards within the city of Aqaba, Jordan

Ground-penetrating radar (GPR) was used in an effort to locate a major active fault that traverses Aqaba City, Jordan. Measurements over an exposed (trenched) cross fault outside of the city identify a radar signature consisting of linear events and horizontal offset/flexured reflectors both showing a geometric correlation with two known faults at a control site. The asymmetric linear events are consistent with dipping planar reflectors matching the known direction of dip of the faults. However, other observations regarding this radar signature render the mechanism generating these events more complex and uncertain. GPR measurements in Aqaba City were limited to vacant lots. Seven GPR profiles were conducted approximately perpendicular to the assumed strike of the fault zone, based on regional geological evidence. A radar response very similar to that obtained over the cross fault was observed on five of the profiles in Aqaba City, although the response is weaker than that obtained at the control site. The positions of the identified responses form a near straight line with a strike of 45°. Although subsurface verification of the fault by trenching within the city is needed, the geophysical evidence for fault zone location is strong. The location of the interpreted fault zone relative to emergency services, military bases, commercial properties, and residential areas is defined to within a few meters. This study has significant implications for seismic hazard analysis in this tectonically active and heavily populated region.

Qualitative evaluation of the mineralogical and chemical composition of dry deposition in the central and southern highlands of Jordan.

The chemical and mineralogical composition of dry deposition in the western highlands of central and south Jordan at the end of the summer season 2000, reflect the composition of soils in addition to anthropogenic activities at these areas. Calcite predominated in the central region whereas calcite and quartz are the dominant minerals in south Jordan. The concentrations of Hg, Cr, Ni, Cu, Pb and Zn were higher in central Jordan, which might be attributed to higher anthropogenic activities than south. On the other hand, Fe, Mn, Ti, Ba, Sr, Y and Rb were higher in the south of Jordan reflecting the composition of soil at these sites. At Aqaba city, the only port of Jordan, where Cr, Cd, As and S were higher than other areas. This variation might be attributed to the contribution of phosphate dust in the atmosphere through handling processes.

Ground motion characteristics of the November 1995 Aqaba earthquake

The paper documents the main characteristics of the seismic activity in Jordan's southern port city of Aqaba associated with the earthquake swarm in November 1995. A review is made of the seismicity of the Aqaba region. Damage due to the 22 November earthquake is reported and so are the measurements of this activity and its aftershocks. Durations and frequency contents are computed and analyzed. Power spectral densities are generated. The strong influence of magnitude on frequency content is noted and discussed. The amplification of soil to the rock motion is investigated both based on recorded data and using an analytical approach. The computer program SHAKE91 is used to study the soil response of the Aqaba profiles using a previous record on rock for a 1979 earthquake on the same fault. Correlation is found between recorded data and the theoretical model for soil amplification. Recommendations are made for designers including design response spectra for two soil profiles in Aqaba.

The Major Gulf of the Aqaba Earthquake, 22 November 1995 – Maximum Intensity Distribution

The major earthquake of 22 November 1995, with a moment magnitude MW = 7.1 and a local magnitude ML 6.2, was the beginning of a seismic swarm that occurred in the central part of the Gulf of Aqaba. During this swarm, thousands of earthquakes occurred with local magnitude ranging between 2 and 6.2 from 22 November 1996 to 31 December 1997, when 2089 earthquakes were detected and/or analyzed by the Jordan Seismological Observatory (JSO). The major earthquake strongly affected the near shoreline cities (Figure 1). The maximum observed intensity on these cities was VIII on the modified Mercalli intensity (MMI) scale. A questionnaire was distributed in the main cities of Jordan one week after the major earthquake. The results of this investigation, which demonstrated the observed intensity distribution for Aqaba city, shows a relationship between local conditions, such as geological foundations and topographical characters, and the extent of the destruction. This conclusion was supported by the maximum peak ground acceleration (PGA) measurements inside Aqaba and Eilat cities. From the results of this questionnaire compiled inside Jordan, and other reports and readings compiled from other nearby countries outside Jordan, a preliminary regional iso-intensity map for this major earthquake of 22 November 1995 is presented in this study.

Design response spectra for Aqaba City-Jordan

Strong motion records for earthquakes epicentred in the Gulf of Aqaba during swarms in August 1993 and November 1995 are studied. These recordings are made at two sites in the City of Aqaba, one near the seashore and the other inland. The former site has deep alluvial profile with low shear-wave velocity, while the latter's soil profile is constituted of shallow stiff alluvium overlaying rock. The magnitudes of these events range from 4·8 to 6·2 on the Richter scale. Ground motion on the seashore site is much greater than the inland site. Response spectra are derived for each of the available accelerograms. Thirteen records at the inland site are statistically treated to arrive at mean response spectrum using 5 per cent damping. The derived spectra are found to be sharp with small plateau, this is associated with small peak displacement. Empirical site-dependent response spectra are also derived based on recent research and on recommendations of the UBC'97. Comparison is made between the empirical and measured spectra. These were found to be quite close for the inland site but data are not sufficient for the seashore site to make a conclusive comparison. Copyright © 1999 John Wiley & Sons, Ltd.

Dynamic site response evaluation of the Port City of Aqaba (Jordan) employing the equivalent linear method

As part of an ongoing research program to develop local seismic engineering ground motion parameters for implementation in the Jordanian Seismic Building Code, a practical contribution is made to determine the local site coefficient (S) for the Port City of Aqaba, southern Jordan. Employing probabilistic peak ground acceleration estimates using FRISK, the overall dynamic site response design spectrum is obtained through the calculated response spectrum based on selected soil-rock column profiles applying SHAKE91. The parabolic shape of the S coefficient design spectrum is given by the following relationships:S = 1.06 for Tb/ Ts<= 0.56S = -0.81 + 4.68(Tb/ Ts) -2.38(Tb/ Ts)2for 0.56 < (Tb/ Ts)<=1.43S = 1.00 for Tb/ Ts>1.43where Tband Tsare the structural and site response design periods (in seconds), respectively.Key words: dynamic, site, response, Aqaba, spectrum, design.

Dynamic site response evaluation of the Port City of Aqaba (Jordan) employing the equivalent linear method

As part of an ongoing research program to develop local seismic engineering ground motion parameters for implementation in the Jordanian Seismic Building Code, a practical contribution is made to determine the local site coefficient (S) for the Port City of Aqaba, southern Jordan. Employing probabilistic peak ground acceleration estimates using FRISK, the overall dynamic site response design spectrum is obtained through the calculated response spectrum based on selected soil-rock column profiles applying SHAKE91. The parabolic shape of the S coefficient design spectrum is given by the following relationships:S = 1.06 for Tb / Ts <= 0.56S = -0.81 + 4.68(Tb / Ts) -2.38(Tb / Ts)2 for 0.56 < (Tb / Ts)<=1.43S = 1.00 for Tb / Ts >1.43where Tb and Ts are the structural and site response design periods (in seconds), respectively.Key words: dynamic, site, response, Aqaba, spectrum, design.

Soil properties, foundation stability, groundwater conditions, characteristics of building stones and mortar used in construction and proposed measures for restoration at the site of ancient Ayla in a Qaba, Jordan

Ancient Ayla in Aqaba, Jordan was destroyed during a major earthquake incident that occurred in Aqaba in 1067 AD. The Gulf of Aqaba is a seismically active region. The latest strong earthquake incident occurred on November 22, 1995 when an earthquake of local magnitude 6.2 rocked the Gulf of Aqaba region. The main shock was followed by thousands of aftershocks. The Gulf of Aqaba-convering the geologic coordinates 28.0–29.6 N; 34.5–35..2 E is one of two natural bays surrounding the Sinai Peninsula which itself is located at the northernmost end of the Red Sea. The soil profile underlying Aqaba city consists of interlayering of various sedimentory Holocene Alluvium deposits.

A Survey of Radon Levels in Jordanian Dwellings During an Autumn Season

Previously calibrated dosemeters containing CR-39 plastic detectors were used to measure radon levels in Jordanian cities during the autumn. The averages of radon concentrations in the different cities obtained in this work range from 29.3 to 99.7 Bq.m -3 . It was found that the city of Karak possesses the highest radon concentrations and the city of Aqaba possesses the lowest. Thus, the calculated average radon levels in Jordanian dwellings as a whole was found to be 56.7 Bq.m -3 . The average radon induced lung cancer risk during a lifetime for dwellers of the cities under study was found to range from 0.12% to 0.41%.

Eilat 's Artificial Lagoons Project On TheRed Sea - Israel

Eilat city is located in the southern part of the state of Israel on the coast line of the Red-Sea, 10 Km west of Aqaba city in Jordan. The Red Sea is one of the most interesting seas in the world for scuba diving and it makes Eilat the most attractive area for recreation in Israel. Swimming, scuba diving, sailing, water skiing, wind surfing and other recreation activities can be enjoyed in Eilat throughout the whole year. In the year 1992 it was decided by the Eilat Foreshore Development Company Ltd. which is a government company to continue with the realisation of the master plan consisting of the Artificial Lagoons project. The building of the project will enable the company to provide more areas for building hotels (3,000 rooms), enlarging the existing marina, and providing more swimming area by adding a 1000 meters length of water line with sandy beaches. Construction works were started in September 1993 and are expected to be finished in September 1995.