ABSTRACT The Santa Rosalía basin (Baja California Sur, México) contains a rich record of late Cenozoic volcanism, faulting, and sedimentation that provides a crucial constraint on the timing of marine flooding from the Pacific Ocean into the nascent Gulf of California oblique rift, yet the precise age of the basin is uncertain. Previous studies used reconnaissance paleomagnetic data and a 40Ar/39Ar age of 6.76 ± 0.90 Ma on the intrabasinal Cinta Colorada tuff to estimate a depositional age of ca. 7.2–6.3 Ma for the marine Boleo Formation and initial flooding of the central Gulf of California. Here, we present a large (n = 2091) detrital zircon U-Pb geochronology data set from the Boleo Formation that indicates a maximum depositional age of 6.35 ± 0.21 Ma for pumiceous sandstone at the base (below the basal limestone), a revised age of 5.86 ± 0.06 Ma for the Cinta Colorada tuff in the middle, and a maximum depositional age of 5.70 ± 0.21 Ma for the top. Detrital zircon age spectra suggest a local provenance for the Boleo Formation involving recycling from underlying Oligocene–Miocene strata in proximal source areas. Integration of detrital zircon ages with existing paleomagnetic data suggests that the lower ~30 m of the Boleo Formation accumulated during normal-polarity subchron C3An.1n (6.27–6.02 Ma), and the middle to upper Boleo Formation was deposited entirely during reverse-polarity chron C3r (6.02–5.24 Ma). We therefore reassign the depositional age span of the Boleo Formation to ca. 6.3–5.7 Ma. Although not preferred, a minimum-duration depositional model from ca. 6.1 to 5.8 Ma is also permissible if a consistently high sedimentation rate of ~0.4– 1.0 mm/yr is inferred. This revised younger age for the Boleo Formation implies marine incursion in the central Gulf of California at ca. 6.3 Ma, ~1 m.y. younger than previously thought. We envision that regional marine flooding occurred during a very short (<100 k.y.) event that inundated a narrow tectonic trough over a distance of at least ~1000 km along the plate boundary from the central Gulf of California to the Salton Trough and reaching into the present-day Lower Colorado River Valley. This study also demonstrates the utility of large-volume and large-n detrital zircon studies in establishing the ages of sedimentary successions deposited over very short time spans (<1 m.y.) and/or during relative lulls in magmatism and geomagnetic reversals.

This paper discusses the relationship between dynamic landscape change resulting from tectonic activity and patterns of human land use and human development. Archaeological studies of human settlement in its wider landscape setting usually focus on climate change as the principal environmental driver of change in the physical features of the landscape, even on the longer time scales of early human evolution. Tectonic processes are usually assumed to operate too slowly to be of any significance except as the source of occasional disruptive events, or at best to have some indirect effect on climate change as a result of long-term regional uplift. Herein, examples are shown from Europe and Africa to illustrate the ways in which changes of significance to human settlement can occur at a range of geographical scales and on time scales that range from lifetimes to tens of millennia. We emphasize that these changes are not always or necessarily destructive in their impact but can also create and sustain attractive conditions for human settlement and that these conditions have exercised powerful selection pressures on human development.

The close spatial relation between ancient civilizations and active tectonic boundaries is robust in the Eastern Hemisphere but counterintuitive given the seismic disadvantages it implies. Explanations for the observation remain debatable, and no single explanation seems sufficient. Some possibly important factors are unrelated to seismicity, e.g., the influence of tectonism on local water resources and on resource diversity. When examined on finer spatial scales, the relation is still robust. A quantifiable influence of tectonism on civilization locations even along Mediterranean shores is suggested by their distribution. The stronger links of tectonism with derivative civilizations suggest a role of ancient trade connections. Several clues point to cultural response as an important ingredient in the dynamics resulting in the spatial relation. These are: correlation between static character and location of civilizations relative to tectonic locus; archaeologic and historic records of accelerated cultural (especially religious) change following tectonic events; and evidence that the spatial relation evolves through time via trade goods and routes. Archaeoseismology is in a key position to provide additional clues to this paradoxical relation in at least three ways: (1) providing detail on evolving societal response; (2) determining the most pertinent tectonic styles; and (3) determining the role of seismicity in Neolithic cultures that eventually became civilizations.

Mansurah, the eighth-century Arabic capital of Sindh province, Pakistan, flourished for a mere 200 yr. Its destruction by an earthquake ca. 980 A.D. was first proposed by archaeologists who reported the discovery of crushed skeletons amid dateable coins found among its rubble. An abrupt natural death to the city was challenged by others who noted that the absence of wood or valuables was consistent with the city being sacked and systematically looted. The recent discovery of four decorated door knockers beneath the collapsed walls of one of the largest structures in Mansurah, however, reopens the case for an earthquake, since an invading army would almost certainly have removed them as booty. We suggest that an earthquake not only destroyed the city and its suburbs (intensity ≈ VIII), but resulted in postseismic avulsion of the river on which its citizens depended for agriculture, sanitation, and trade. Since natural levees have been observed in India to collapse in intensity VII shaking, it is unnecessary to invoke coseismic uplift as a requirement for upstream river avulsion. The absence in the past two centuries of large earthquakes in the region has resulted in central Sindh being depicted as a region of low seismic hazard, yet in 1668, in the same province, an earthquake destroyed nearby Samawani and also initiated avulsion of the Indus. A case can be made for reevaluating the five millennia of archaeological ruins in Pakistan to establish a long-term view of seismicity unavailable from the short instrumental record.

The prime cause of the relocation of one of the first villages founded in Venezuela by Spaniards in the early seventeenth century was likely motivated by earthquakes. San Antonio de Mucuñó, located in the Merida Andes ~200 km south-southeast of Maracaibo, was subjected to the effects of landslides triggered by a series of seismic events that took place in and around the year 1674. Historical documents, the geological and seismo-tectonic setting, and paleoseismic data support the conclusion that the earthquakes of 1674 occurred on the nearby, seismically active Bocono fault.

This work sheds light on one of the most important earthquakes in Venezuelan history. At 16:07 on Holy Thursday, 26 March 1812, Caracas and the surrounding province of Venezuela suffered a very destructive earthquake. The earthquake occurred at a time of great political, economic, and social upheaval, with the beginning of the republican revolution and the Spanish royalist military response. Within this historical context of conflict, documentary information may be biased and subjective. This chapter is a methodological and epistemological analysis of the 1812 earthquake damage from letters and manuscripts and an interpretation of the social impact of the earthquake within ideological, subjective, and political context. The widespread destruction of the city of Caracas was heterogeneous in its distribution. Damage was determined largely by the differences in the construction style and quality and by the maintenance status of the building. Based on analyses of three funeral books from the era, the number of earthquake victims in Caracas in 1812 may have been close to 2000. This value is lower than regional estimates of the death toll.

This paper examines the development of a crisis over a critical military-security issue raised by the severe earthquakes that destroyed defensive structures throughout Nur al-Din's Sultanate of Syria, the Crusader Principality of Antioch, and the County of Tripoli. The earthquakes that struck Syria in 1157 and 1170 are well documented by contemporary historians. The accounts of destruction concentrate on the collapse of many fortresses and town walls. This circumstance strongly influenced regional politics and military affairs. While the first earthquake led to an increase in tension and a rise in violence between the Crusader Kingdom of Jerusalem and the Muslim Sultanate in Syria, the destruction wrought by the 1170 earthquake forced the two sides to accept a formal peace treaty. The two case studies presented here examine the impact of earthquake destruction on decision makers in the complex international arena of medieval Syria.

The earliest use of seismological observation to identify and date archaeological sites in western Crete was attempted by Captain T.A.B. Spratt in the late nineteenth century. Since then, the development of the subdiscipline of archaeoseismology has offered a great deal to our understanding of western Crete, especially regarding major sites such as Phalasarna and Kissamos. This paper is a review and summary of archaeoseismology in western Crete, presenting the archaeoseismological and excavation evidence from Phalasarna and Kissamos. It also presents evidence from other archaeological sites in western Crete and expresses the potential the region has for future archaeoseismological research.

Earthquake archaeology developed in Japan simultaneously with that in the Mediterranean in the mid-1980s. By 1996, evidence of earthquake occurrence had been documented at 378 sites throughout the archipelago. The main features identified include various results of liquefaction, faults, landslips, and surface cracking. This evidence differs greatly from the standard Mediterranean focus on building damage, and the reasons for the very different natures of archaeoseismology in these world regions are explained herein. This article recounts the development of this new subfield, inspired by the interest of geomorphologist Sangawa Akira and taken to its most recent advances in identifying soft-sediment deformation structures by geoarchaeologist Matsuda Jun-ichirō. The evidence of earthquake activity at archaeological sites can be matched with earthquakes caused by either active fault movement or subduction. The historical record of earthquake occurrence, already documented back to 599 C.E., is extended into the prehistorical record through relative dating of artifacts and features on archaeological sites. Both the identification and the dating of the archaeological evidence of earthquakes can be challenged, though the “territorial approach” gives the data a significance that is not achieved through analysis of single sites.

The field of archaeoseismology has been plagued by a persistent problem. The problem has been the integration of several lines of evidence to produce a holistic conclusion without entering into a situation of circular reasoning, wherein the sources are used to build on each other without foundation. The four main sources of evidence are historical texts, epigraphy, archaeology, and geology. Any seismic event may appear in any or all of them, but only the most extreme events in fortuitous locations would be expected to appear in all four. This paper uses some aspects of the interpretation of the 551 C.E. earthquake in the Levant to illustrate how this circular reasoning can develop, and how it tends to corrupt the different lines of evidence. We conclude with a suggested new approach, making the database of regional seismic events both more specific and more complete.

Srinagar, the capital city of Kashmir, has been shaken numerous times by earthquakes in the past millennium, most recently by damaging earthquakes in 1885 (M 6.2, 30 km to the west) and 2005 (M 7.6, 200 km to the west) with estimated EMS (European Macroseismic Scale) intensity VI–VII. Earthquakes in Kashmir in earlier historical times are known only from fragmentary archival sources. We present and analyze unique, repeat photographs of the Pandrethan Temple near Srinagar, which we conclude can provide clues to the severity of nineteenth-century earthquakes. Photos taken in 1868 and 1885 and recently show that the temple, a 5.5-m-square masonry-block structure constructed ca. A.D. 920, was undamaged by these two earthquakes. We conclude that displaced blocks visible in the earliest extant photograph are the result of stronger shaking in the past, the most probable causal earthquake being in 1828. Considering the fragility of the structure, we conclude that anything greater than EMS intensity IX would have caused structural collapse. We thus conclude that Pandrethan has not experienced EMS intensity greater than VIII in the past 200 yr, and possibly not in the past millennium.

Civilizations have existed in the proximity of the Indus River Valley regions of modern Pakistan and India from at least 3000 B.C. onward. Geographically, the region encompasses a swath of the Makran coast, the alluvial plain and delta of the Indus River, and the Runn of Kachchh. The regional tectonic setting is controlled by the collision of the Indian and Eurasian plates and the subduction of the Arabian plate beneath the Eurasian plate. Earthquakes have undoubtedly struck many ancient sites, but finding their footprint in a riparian environment represents a challenge for archaeoseismology. However, some insight into seismoarchaeological indicators can be gleaned from examining the earthquake effects produced by historical infrequent large-magnitude events that have occurred in the region. Studies of these earthquakes emphasize the importance of repeated reconstructions, direct faulting, river damming from seismic uplift, and coastal elevation change as indicators of past earthquakes. Examples of past earthquake effects are presented for Banbhore in the Indus Delta, Brahmanabad, and the Harappan sites of Kalibangan and Dholavira. Future hermeneutic investigations in the region need to incorporate a seismological/tectonic perspective and not rely solely on serendipity.

The Bolonia Bay, close to the Strait of Gibraltar, hosts the Roman ruins of Baelo Claudia. In the first and third century A.D., this ancient town was affected by two earthquakes. Several earthquake-related damages can be found inside the ruins, and the adjacent mountain ranges show features of Quaternary activity. Extensive paleoseismological and archaeoseismological investigations have been conducted at the archaeological site and in its environs. The first 14 C dating results from damaged infrastructure are presented in this paper, together with the preliminary results of fault-trenching on one of the closest suspect seismogenic faults near the archaeological site. The observations have been quantified using the two logic trees for paleoseismology and archaeoseismology. Our results show that a mere paleoseismological classification of the geological features leads to a paleoseismic quality factor (PQF) of 0.03, which is low compared to other studies. Taking into account the additional information from archaeoseismological work (archaeoseismological quality factor [AQF] is 0.5), it becomes clear that the Baelo Claudia study site provides an opportunity for detailed earthquake investigations. Therefore, it has a high potential for reliable seismic hazard analyses. A complementary application of both logic trees is recommended in future studies if sufficient data are available.

During the archaeological and geoarchaeological surveys on the island of Zakynthos, Greece, it has been noted that the distribution and preservation of archaeological remains of Zakynthos present spatially different characteristics. In general, archaeological pottery finds and architectural remains in the eastern part of the island appear to be more fragmented and more widely distributed than in the western part of the island. Due to the high seismicity in the region, the question has come up whether a correlation between seismic activity and distribution and preservation conditions of archaeological remains exists or not. In order to investigate the mentioned relationship, we looked at the cumulative effect of continuing earthquakes for the last hundred years on the island of Zakynthos. We used ground acceleration to quantify the earthquake-induced damage. The predicted cumulative destruction intensity is presented on a map, and it illustrates that we can cautiously attribute the distribution difference of the archaeological remains with different preservation conditions to the seismic activity on the island. It is hoped that this study will initiate new scientific research into the characteristics of the distribution of archaeological remains in seismically active areas. In addition, it is to be expected that this study will contribute to in situ preservation studies relating to the long-term effect of seismic activities on the archaeological record.

Seismic-related damages of archaeological structures play an important role in increasing our knowledge about the timing and magnitudes of historical earthquakes. Although quantitative data should form the basis of objective archaeoseismological methods, most studies still do not rely on such methods. Ground-based LIDAR (light detection and ranging) is a promising, rather new, scanning technology that determines spatial position of an object or surface and provides high-resolution three-dimensional (3-D) digital data. Using LIDAR, we mapped the damage and overall attitude of a Roman theater in the ancient Lycian city of Pinara (500 B.C.–A.D. 900), located at a faulted margin of the Eşen Basin (SW Turkey). An average 0.81°NW tilt of the 20 seating rows could be computed from the LIDAR data. Conventional compass readings of these seating rows did not provide the same results because errors involved with this method are generally >2°. The tilt direction appears perpendicular to the NE-trending basin-margin fault, suggesting that fault-block rotation is the most likely mechanism to have induced the systematic tilt of the theater. The estimated 4 m offset on this normal fault should be seen as a rough estimate of the total displacement and was likely produced by several (more than one) earthquakes with magnitudes of M = 6–6.8. This is consistent with historical records that mention several large earthquakes during the Roman period.

The ruins of the ancient settlement of “El Tolmo de Minateda” are one of the best representative archaeological sites within the Albacete Province (SE Spain), characterized by a well-preserved record for the last ~3800 yr. The present ruins record an almost continuous of occupation from the Late Bronze Age (Iberian Culture, from ca. third century B.C.) to the High Middle Ages, including intervening and successive Roman, Visigoth, and Muslim city remains. The eventual Muslim settlement was abruptly abandoned and destroyed during the ninth–tenth centuries A.D., leaving a lack of any archaeological evidence of war or decay. Another previous anomalous archaeological episode of abrupt city abandonment and destruction is recorded during the Visigothic Period (seventh century). The archaeological record of this city supports evidence for earthquake damage linked to both periods of city abandonment and destruction, including oriented collapse of walls, watchtowers, and columns, oriented cracking of walls and column drums, as well as in situ broken pottery, abrupt abandonment of kilns, and anomalous sedimentary infilling of canals and water-supply facilities. Additionally, large-scale rockfalls containing Visigothic carved tombs are also apparently associated with both episodes, constituting one of the few instances of combined geoarchaeological evidence of earthquake ground effects ever reported. As a means of testing the theoretical archaeoseismic potential of this site, we obtained an archaeoseismic quality factor (AQF) value of 0.074.

Damages from two major earthquakes are identified in medieval Al-Marqab citadel (Latin: Margat) in coastal Syria. Built by the Order of St. John (Hospitallers) in the twelfth–thirteenth centuries, the hilltop fortification has masonry walls made with and without mortar, using the opus caementum technology (Roman concrete). V-shaped and U-shaped failures, single-corner and symmetrical corner collapses, and in-plane shifts of ashlar masonry walls are identified and dated by historical and archaeological methods. The azimuth of displacement is NE-SW for the older damages of the Crusader period (A.D. 1170–1285), possibly related to the A.D. 1202 earthquake. A later, NW-SE displacement occurred during the Muslim period (post-1285). The 1202 earthquake produced at least VIII intensity on the MSK scale at Al-Marqab, which is higher than previously considered.