IS THERE A NEAR-FIELD FOR SMALL-TO-MODERATE MAGNITUDE EARTHQUAKES?

The major hazard posed by earthquakes is often thought to be due to moderate to large magnitude events. However, there have been many cases where earthquakes of moderate and even small magnitude have caused very significant destruction when they have coincided with population centres. Even though the area of intense ground shaking caused by such events is generally small, the epicentral motions can be severe enough to cause damage even in well-engineered structures. Two issues are addressed here, the first being the identification of the minimum earthquake magnitude likely to cause damage to engineered structures and the limits of the near-field for small-to-moderate magnitude earthquakes. The second issue addressed is whether features of near-field ground motions such as directivity, which can significantly enhance the destructive potential, occur in small-to-moderate magnitude events. The accelerograms from the 1986 San Salvador (El Salvador) earthquake indicate that it may be unconservative to assume that near-field directivity effects only need to be considered for earthquakes of moment magnitude M 6.5 and greater.     

A global–historical sociology of power: on Mann's concluding volumes to The sources of social power

Michael Mann's long‐anticipated volumes, The sources of social power, volume 3: global empires and revolution, 1890—1945 and The sources of social power, volume 4: globalizations, 1945—2011 complete Mann's career‐spanning project. Compared to previous volumes in the series, these works are much more global in scope. They address topics such as global wars, empires, social citizenship across the industrialized world, economic recessions and climate change. In this way they rectify omissions in Mann's previous work, even while continuing to deploy Mann's previous IEMP (ideological, economic, social, political) model of power. However, three shortcomings remain: first, the books do not adequately deploy the concept of society as power networks; second, they do not offer a conceptualization of global systems or dynamics beyond the sum total of actions by individual states or actors; and third, they retain the standpoint of power in their analyses. Despite these shortcomings, these volumes offer a masterful global history of power over the past century and a half and make long‐lasting contributions to the historical sociology of power.     

The Scale and Impact of Viking Settlement in Northumbria

DISCOVERIES AT the Viking winter camp at Torksey indicate that the armies that invaded Anglo-Saxon England in the late 9th century were much larger than is often assumed, and that a literal reading of the Anglo-Saxon Chronicle’s assessment of the size of Viking fleets may, after all, have been correct. Furthermore, study of the Torksey metalwork assemblage has allowed the identification of the archaeological signature of the Viking Great Army, and when applied to Cottam, it confirms the identification of an initial phase of raiding by an element of the Army, followed shortly thereafter by settlement represented by the development of a hybrid Anglo-Scandinavian culture. Taken together, over 25 categories of non-ferrous artefacts are diagnostic of Viking or Anglo-Scandinavian activity in Northumbria. Applying this model to sites, largely known only from metal-detecting, we can observe a common pattern. At the majority of sites, a large and fairly standardised middle Anglo-Saxon finds assemblage is succeeded by just a few Viking finds, which we attribute to raiding following Halfdan’s return to Northumbria with part of the Great Army in AD 876. At a smaller number of sites, assemblages of Anglo-Scandinavian finds relate to the establishment of settlements by the new landowners. The overall picture is of major settlement disruption and dislocation of existing land holdings and populations in the late-9th century. This demonstrates, for the first time from archaeological evidence, the scale and impact of Viking activity in Northumbria.