Earthquakes and archaeology

This article examines the use of archaeological evidence for the assessment of historical earthquakes in the Eastern Mediterranean region and Middle East, long before the advent of modern seismology. We ask the questions when and where have large earthquakes happened in the past? How can this evidence contribute to our scientific understanding of earthquake activity? Is it possible on literary and archaeological grounds to distinguish between earthquake damage and damage from other causes? It is found that archaeological evidence for an earthquake is not always clear or unambiguous and that there is a need for collaboration between archaeologists, historians, geologists, engineering seismologists and workers in other disciplines, to evaluate the traces of earthquakes in excavations, both for understanding their effects at the site and for the information they can provide about the nature of the earthquake implicated.     

PSHA for Broad-Band Strong Ground-Motion Hazards in the Saronikos Gulf,Greece, from Potential Earthquake with Synthetic Ground Motions

We perform a probabilistic seismic hazard analysis (PSHA) for broad-band strong ground motion within the Saronikos Gulf region, Greece, from potential earthquakes along the 30 km long Aigina fault in the northern part of the Gulf. We perform the PSHA utilizing empirical Green’s functions (EGFs) merged with synthetic Green’s functions (SGFs) along with models of finite rupture in place of standard “attenuation relations.” Our approach considers all significant magnitudes for PSHA and full broadband ground motion simulations. Calculations are source and site specific, and could reduce uncertainties in estimating standard engineering parameters. We use a range of rupture scenarios for all significant magnitude earthquakes along the fault. The hazard calculation is for frequencies 0.0– 15.0 Hz. Recordings of small earthquakes from an onshore/offshore local seismic array were used as EGFs for frequencies of 1.5–15.0 Hz, the finite difference code E3D was utilized to synthesize SGFs for frequencies 0.0–1.5 Hz, and an algorithm for merging the EGFs with SGFs was developed. The full-waveform calculations are important for non-linear dynamic analysis of structures in the coastal zone and potential hazard to long period structures. Results of proposed PSHA identify 2%, 10%, and 50% hazard at the selected sites of Saronikos Gulf.

Finally, we compare our PSHA results to those obtained by standard practice which involves prediction equations (GMPEs) recently developed in the Next Generation Attenuation (NGA) project and empirical predictive attenuation relations proposed for Greece. We believe that differences with the NGA results are due to site- and source-specific information utilized in this study, and incorporation of this information may significantly reduce the uncertainty in seismic hazard calculations.     

Empirical Green's Functions Modified by Attenuation for Sources Located at Intermediate and Far Distances from the Original Source

We present a scheme to modify empirical Green's functions by attenuation considering: (1) geometrical spreading; (2) decay in high frequency; (3) regional attenuation; and (4) phase of the signal. The accelerograms computed with the proposed simulation method are compared, in time and frequency domains, with strong ground motions from subduction and intermediate-depth earthquakes recorded in Mexico. It is shown that this simple empirical Green's functions technique can synthesize both the shape and amplitude of the response spectra in the site, considering a postulated seismic source located at different distances from the original one.     

Seismic Response of Bridges Subjected to Different Earthquake Types Using IDA

Incremental Dynamic Analysis (IDA) was used to evaluate the seismic response of straight, continuous 4-span bridges with different sub-structure configurations. Three different record sets were chosen to represent three different earthquake types which can occur for a site such as Vancouver (i.e., crustal, subduction interface, and subduction inslab earthquakes). Seventy eight records were considered in each set (i.e., a total of 234 records) and the capacities of the bridges were evaluated using a fast IDA algorithm. A simplified method to account for the effects of spectral shapes was used. Different subsets of the records with specific characteristics were also used in the IDA. The bridges were designed and evaluated for two different design force modification factors and bridges with different degrees of irregularity were studied. Comparisons of the IDA results obtained indicated that in most of the cases the interface record sets resulted in lower median collapse capacities and hence were the most critical of the ground motions studied.     

THE SEISMICITY OF THE MARMARA SEA AREA 1800–1899

The paper presents an extended summary of the most important earthquakes of the 19th century in the Marmara Sea region in north-west Turkey. We can find no evidence for a significant earthquake occuring during the first half of the 19th century, a period during which the west terminal of the North Anatolian fault system was much more active further west.This variation of activity with time of segments of fault zones, such as the Anatolian, is typical; the smaller the segment considered the longer the sampling period needed for moment rates and hazard estimates to be reliable. We find that the larger and some of the smaller events of the 19th century are clearly associated with known active faults which have generated earlier and later damaging earthquakes.     

Dendroarchaeology of the mid-first millennium AD in Constantinople

The 1st millennium AD was a time of great transition in Europe and the Mediterranean. At the heart of the Byzantine Empire, Constantinople (modern day Istanbul) was a pivotal trade hub for the Aegean region. Establishing a precise and accurate dating framework for the development of this remarkable city and a chronological reference for this critical time period for the Mediterranean region is of great importance to a wide range of scholars. Here we present a new 213 year tree-ring record from 89 oak samples placed in time by dendrochronology and supported by radiocarbon analysis and historical documentation. It represents the middle of the first millennium AD in Constantinople. The tree-ring series are derived from pilings recovered from the extraordinary excavations of the so-called “Theodosian harbor” at Yenikap?, Istanbul, along with timbers from other sites and buildings around the city, including one of the most famous sites on the Istanbul sky-line—Hagia Sophia. They provide potential for new insight into a time period in which earthquakes, the Justinianic plague, and even a possible tsunami struck the city, and during which dramatic changes in climate have been recorded in other paleoenvironmental proxies. The chronology is the first published tree-ring series from the Aegean region to cover the ‘event’ years of AD 536–7 and 542 which are characterized by anomalous growth in other tree-ring series from around the world, but interestingly these event years are not evident in this tree-ring sequence.     

THE 9 JULY 551 AD BEIRUT EARTHQUAKE,EASTERN MEDITERRANEAN REGION

Analysis of the Byzantine primary and secondary sources for identifying the historical earthquakes in Syria and Lebanon reveals that a large earthquake (M _s =7.2) occurred in July 9, 551 AD along the Lebanese littoral and was felt over a very large area in the eastern Mediterranean region. It was a shallow-focus earthquake, associated with a regional tsunami along the Lebanese coast, a local landslide near Al-Batron town, and a large fire in Beirut. It caused heavy destruction with great loss of lives to several Lebanese cities, mainly Beirut, with a maximum intensity between IX-X (EMS-92). The proposed epicentre of the event is offshore of Beirut at about 34.00°N, 35.50° E, indicating that the earthquake appears to be the result of movement along the strike-slip left-lateral Roum fault in southern Lebanon.     

Experimental Out-Of-Plane Behavior of Brick Masonry Infilled Frames

ABSTRACT

The vulnerability of masonry infills within reinforced concrete (rc) frames under out-of-plane loading induced by earthquakes has been observed in several past earthquakes through severe damage and often total collapse. Although the infill panels are assumed as non-structural elements, their damage or collapse is not desirable, given the possible consequences in terms of human life losses and repair or reconstruction costs.

Therefore, it is important to gather better insight on the out-of-plane behavior of existing infills so that strengthening guidelines can be derived. In this scope, the main objective of this study is to analyze the out-of-plane experimental behavior of masonry infilled frames that are characteristic of Portuguese buildings and can be seen in other south European countries. In the experimental study carried out, different parameters affecting the out-of-plane response of infilled frames were considered, namely, workmanship, existence of openings and prior in-plane damage. The experimental program was designed to test six half-scale specimens. The out-of-plane loading was applied uniformly to the brick infills by means of an airbag to simulate the effect of earthquakes.     

Seismic Response of Base-Isolated Benchmark Building with Variable Sliding Isolators

The seismic response of base-isolated benchmark building with variable sliding isolators like variable friction pendulum system (VFPS), variable frequency pendulum isolator (VFPI), and variable curvature friction pendulum system (VCFPS), along with conventional friction pendulum system (FPS), was studied under the seven earthquakes. The earthquakes are applied bi-directionally in the horizontal plane ignoring vertical ground motion component. The shear type base-isolated benchmark building is modeled as three-dimensional linear elastic structure having three degrees of freedom at each floor level. Time domain dynamic analysis of the benchmark building was carried out with the help of constant average acceleration Newmark-Beta method and nonlinear isolation forces was taken care by fourth-order Runge-Kutta method. The base-isolated benchmark building is investigated for uniform isolation and hybrid isolation in combination with laminated rubber bearings through the performance criteria and time history response of important structural response parameters like floor accelerations, base displacement, etc. It is observed that variable sliding isolators performed better than conventional FPS due to their varying characteristic properties which enable them to alter the isolator forces depending upon their isolator displacements thus improves the performance of the structure. The VFPS efficiently controls large isolator displacements and VFPI and VCFPS improve super structural response on the cost of isolator displacement. It is also observed that the hybrid isolation is relatively better in comparison to the uniform isolation for the benchmark building.     

THE SHADOW-ZONE OF LARGE ITALIAN EARTHQUAKES. EARLY JOURNALISTIC SOURCES AND THEIR PERCEPTION OF 17TH-18TH CENTURIES SEISMICITY

From their earliest beginnings in the 16th century, journalists never failed to find earth-quakes interesting. As a result, early journalistic sources offer a huge hoard of original earthquake data, mostly untapped to this day for seismological purposes [Camassi and Castelli, 2003]. In the aftermath of large earthquakes, the journalists of the 17th and 18th centuries tended to react in two ways. Either their interest for seismic news would increase, leading them to hunt for more news of the same kind, or it would focus exclusively on the “big one” to the detriment of lesser contemporary earthquakes. In the first case, it was possible that more earthquakes than usual would be given coverage; but in the second case more earthquakes than usual were likely to be overlooked and shadowed by the larger event. Through a comprehensive cross-check of Italian early journalistic sources, this paper attempts to highlight the “shadow-zones” of some major 17th–18th centuries Italian earthquakes.     

唐代地震灾害时空分布初探

中国位于太平洋西岸地震带 ,是个地震多发国家 ,历史时期就曾发生过多次大地震。本文在前人研究的基础之上 ,对唐代 (公元 6 18— 90 7年 )中国地震灾害的发生频率及时空分布作了分析 ,并获得几点规律性结论。     

Communications,Qajar Irredentism and the Strategies of British India: The Makran Coast Telegraph and British Policy of Containing Persia in the East (Baluchistan)—Part II

Persian territorial designs in Baluchistan clashed with British interest to construct an Indo-European telegraph line through the Makran Coast, where Britain had close local allies in dispute with Persia. The British prime interest being the speedy construction of the line, they decided on bypassing these disputed territories by connecting Bushehr, through submarine cable, with Gwadar—which they believed, contrary to the Persians, to be non-Persian. The Persian government protested against the British infringement of her sovereign rights, adopting both diplomatic and military approaches. This forced the British government to check the legality of the Persian claims. But the arbitrary was neither neutral nor fair, with Britain opposing the suzerainty of Persia over the chiefs of western Makran, while acknowledging the right of conquest by others elsewhere on the coast. This was in line with British policy of favoring governments bordering British India over Persia. Although unable to change the arbitrary, the Persian government still managed, in spite of her military weakness, to drag the British government into a hard bargain and tough negotiations.     

THE COLFIORITO EARTHQUAKE SEQUENCE OF SEPTEMBER–OCTOBER 1997: SURFACE BREAKS AND SEISMOTECTONIC IMPLICATIONS FOR THE CENTRAL APENNINES (ITALY)

Between September–October 1997, a seismic sequence with three main shocks (Mw=5.6, 5.9, on September 26, and Ms=5.5 on October 14) struck the Umbria-Marche region in central Italy between the villages of Nocera-Umbra and Sellano. Although earthquake-induced landslides were observed and mapped in the epicentral area along the main active normal faults, no surface faulting was associated with the two first shocks of September 26. In contrast, the third shock of October 14 produced discontinuous coseismic tectonic ruptures (60 m–500 m long) along a total length of 5 km. Surface ruptures strike in the NNW-SSE direction, dip to the SW and show locally en-echelon geometry (either right-or left-stepping). Coseismic ruptures and active faults are in good agreement with CMT focal-mechanism solutions that indicate normal faulting for the three main shocks. These results provide additional information on surface tectonic ruptures caused by moderate-sized earthquakes, yielding some constraints on seismotectonic processes.     

Seismic Vulnerability Assessment and Retrofitting Strategies of Italian Masonry Churches of the Alife-Caiazzo Diocese in Caserta

ABSTRACT

Masonry churches represent the major part of the Italian architectural heritage. Recent earthquakes stressed the high vulnerability of these constructions, provoking heavy structural damage and valuable losses. Different approaches have been developed to assess seismic vulnerability of churches. In particular, the complexity related to more detailed models has induced to define simplified methods, which can be used at territorial scale for a preliminary assessment of structural capabilities of homogeneous assets aiming at providing possible post-earthquake damage scenarios and suggesting general interventions strategies. Therefore, the vulnerability assessment of churches is carried out by subdividing the buildings into separate macro-elements, accounting for different possible collapse mechanisms. In this article, a simplified procedure (M.I.T. 2011) has been applied with reference to churches located in Caserta District, particularly those of the Alife-Caiazzo Diocese, by using the MaChro form compilation, previously developed by the authors. The aim of the study is the application of the above procedure in order to verify the possibility to suggest suitable strategies of intervention for structural retrofitting and seismic risk reduction of the churches located in the area under investigation.     

Injection‐induced seismicity in Carbon and Emery Counties,central Utah

Utah is one of the top producers of oil and natural gas in the United States. Over the past 18 years, more than 4.2 billion gallons of wastewater from the petroleum industry has been injected into the Navajo Sandstone, Kayenta Formation, and Wingate Sandstone in Carbon and Emery Counties, central Utah, where seismicity has increased during the same period. Previous studies have attributed this seismicity to coal mining. Here, we present evidence for wastewater injection being a major cause of the increased seismicity. We show that, in the coal mining area, seismicity rate increased significantly 1–5 years following the wastewater injection, and the earthquakes, mostly with magnitudes <3.0, are concentrated in areas seismically active prior to the injection. Using simple analytical and numerical models, we show that the injection in central Utah can sufficiently raise pore pressure to trigger seismicity within 10–20 km of the injection wells, and the time needed for the diffusion of pore pressure may explain the observed lag of seismicity increase behind the commencement of injection. The b‐value of these earthquakes increased following the wastewater injection, which is consistent with these events being injection‐induced. We conclude that the marked increase in seismicity rate in central Utah is induced by both mining activity and wastewater injection, which raised pore pressure along preexisting faults.     

A Pilot Study in Odontochronology for the Pig Domestication Question in North‐Central China

In this paper, we report results of the pilot study in which we apply skeletochronological analysis of teeth to a collection of modern Chinese wild boar (Sus scrofa) of known age and date of death. This is the first time that odontochronology has been applied to suids in China. This work allowed us to establish parameters for subsequent analysis of a limited number of Neolithic‐aged Sus (wild boar and possible early domesticated pig) samples from Henan Province. The goal of the research is to contribute to the ongoing reconstruction of Neolithic dietary, health and economic patterns along the Yellow River. Our results are encouraging in that regular seasonal growth patterning is observed in the northern control sample, which is from the same region as our archaeological investigation. Copyright © 2011 John Wiley & Sons, Ltd.     

Carbon and nitrogen stable isotope analysis on the diet of Jomon populations from two coastal regions of Japan

We report on a stable isotope paleodietary reconstruction of Jomon populations in Japan during the Middle to Final Jomon period (ca. 5000–2300 years BP), focusing on dietary differences within and among populations and between regions. Carbon and nitrogen isotope analysis was performed on human and faunal bone collagen from six coastal sites along the Inland Sea in the Sanyo (Ota, Funamoto, and Tsukumo) region and along Mikawa Bay and the Pacific Ocean in the Tokai (Kawaji, Yoshigo, and Inariyama) region. We found that carbon and nitrogen isotope ratios were positively correlated, indicating that the Jomon people consumed a mixed diet of marine (shellfish and marine fish) and terrestrial (C₃ plants and terrestrial mammals) protein. In the Ota samples (n = 25, during the Middle Jomon period, 5000–4000 years BP), sex was one of the main reasons for the intra-population dietary variation. Ota males consumed greater amounts of marine food, while Ota females consumed greater amounts of terrestrial food; these dissimilar diets may have been related to the sexual division of labor. Significant inter-population dietary differences were found, which may have been related to differences in age or site location. Notably, the two coastal regions showed clear isotopic differences. Nitrogen isotope ratios of individuals from the Sanyo region were significantly higher than ratios of individuals from the Tokai region. The individuals in the Sanyo region might have consumed a diet high in aquatic foods, particularly high trophic level marine fish, whereas the individuals in the Tokai region might have consumed a lot of marine shellfish. Another possible reason for the regional isotopic difference might have been different baseline of nitrogen isotope ratios of the marine ecosystems.     

Archeoseismicity and environmental crises at the Sialk Mounds,Central Iranian Plateau,since the Early Neolithic

During the long-lasting cultural sequences of the Shurābeh and Sialk archeological mounds (6200–550 BC) the inhabitants encountered numerous diversified crises along a narrow fertile passageway at the edge of the Central Iranian Plateau Great Desert. Some of the threats may be attributed to earthquakes, drastic climatic changes, and man-made environmental deterioration, which possibly led to the settlement withdrawing at different stages toward a more suitable location. Our study identified the occurrence of a large-magnitude earthquake around 3800 BC along the Kāshān fault, which is well-documented by various lines of circumstantial evidence, including: (i) numerous contemporaneous smashed skeletons and artifacts underneath collapsed walls and ceiling debris in several different areas; (ii) tilted and collapsed walls; (iii) nearly N–S oriented fallen large storage jars; and (iv) nearly vertical deep ground fractures cutting walls and floors of the Sialk III₅ South Mound settlement. Archeological data also shows additional stratigraphic discontinuities and damages that may be attributed to earthquakes. However, damage features in limited exposed trenches are less conclusive and require additional careful excavations. Apparent ancient paleo-architectural innovative attempts to enhance the coherency/elasticity of the structures and minimize earthquake damage to buildings were also noted, suggesting the indigenous earthquake hazard mitigation endeavor. There seems to be a correlation between some site abandonment dates and possible drastic regional draught/cooling events. The natural and anthropogenic impacts addressed in this study constituted major threats to the sensitive archeological settlements at the fringe of the desert and the vicinity of the Kāshān active fault since antiquity.     

A THEORETICAL ATTENUATION MODEL FOR EARTHQUAKE-INDUCED GROUND MOTION

A theoretical attenuation model of earthquake-induced ground motion is presented and discussed. This model is related directly to physical quantities such as source and wave motion parameters. An attenuation formula for rms acceleration of ground motion is derived and verified using acceleration data from moderate-sized earthquakes recorded in Iceland from 1986 to 1997. The source parameters and the crustal attenuation are computed uniformly for the applied earthquake data. Furthermore, attenuation formulas for peak ground acceleration are put forward.