Rapid topographic change measured by high-resolution satellite radar at Soufriere Hills Volcano, Montserrat, 2008-2010

High-resolution satellite radar observations of erupting volcanoes can yield valuable information on rapidly changing deposits and geomorphology. Using the TerraSAR-X (TSX) radar with a spatial resolution of about 2 m and a repeat interval of 11-days, we show how a variety of techniques were used to record some of the eruptive history of the Soufriere Hills Volcano, Montserrat between July 2008 and February 2010. After a 15-month pause in lava dome growth, a vulcanian explosion occurred on 28 July 2008 whose vent was hidden by dense cloud. We were able to show the civil authorities using TSX change difference images that this explosion had not disrupted the dome sufficient to warrant continued evacuation. Change difference images also proved to be valuable in mapping new pyroclastic flow deposits: the valley-occupying block-and-ash component tending to increase backscatter and the marginal surge deposits reducing it, with the pattern reversing after the event. By comparing east- and west-looking images acquired 12 hours apart, the deposition of some individual pyroclastic flows can be inferred from change differences. Some of the narrow upper sections of valleys draining the volcano received many tens of metres of rockfall and pyroclastic flow deposits over periods of a few weeks. By measuring the changing shadows cast by these valleys in TSX images the changing depth of infill by deposits could be estimated. In addition to using the amplitude data from the radar images we also used their phase information within the InSAR technique to calculate the topography during a period of no surface activity. This enabled areas of transient topography, crucial for directing future flows, to be captured.

The historic landscape of the Mendip Hills

When travelling north-east across the Somerset Levels and Moors the eye is drawn to the dark mass of the Mendip Hills, a Carboniferous Limestone ridge which rises abruptly from the flatness of its surroundings. The Historic Landscape of the Mendip Hills explores the archaeology and architecture of this remarkable corner of England, beginning with evidence for the first hunting groups who passed through the region over half a million years ago. Succeeding generations have left their mark on the Hills, from the enigmatic ceremonial structures of the Neolithic and Early Bronze Age, to the ancient farming landscapes and brooding hillforts of the Later Prehistoric period. Field archaeology, combined with architectural and historical enquiry, has also allowed a complex narrative to be constructed for more recent periods of history. This is a story dominated by adaptation and change, evidenced by the developing architecture of manorial centres and the shadowy remains of earlier structures fossilized within village houses. This volume presents a synthesis of the results of recent fieldwork undertaken by English Heritage and traces this region’s remarkable past, revealing ways in which it has shaped the landscape we see and value today.

The ship as symbol in the prehistory of Scandinavia and south-east Asia

The ship is the dominant element in the visual culture of the South Scandinavian Bronze Age, appearing in several different media, including rock carvings, decorated metalwork and above-ground monuments. Discussion has divided between those scholars who interpret this imagery in terms of long-distance exchange networks and those who emphasize its more local significance, including its deployment in mortuary ritual. A strikingly similar system is identified in Southeast Asia and part of Melanesia and can be interpreted through archaeological and ethnographic sources, but in this case there is no need to distinguish between 'practical' and 'symbolic' interpretations of the depictions of ships. This paper summarizes the evidence from this region and suggests that it can offer a fruitful source of comparison for archaeologists working in northern Europe.

On the long-term interannual variability of the east Asian winter monsoon

The East Asian Winter Monsoon (EAWM) and Siberian High (SH) are inherently related, based on prior studies of instrumental data available for recent decades (since 1958). Here we develop an extended instrumental EAWM index since 1871 that correlates significantly with the SH. These two indices show common modes of variation on the biennial (2-3 year) time scale. We also develop an index of the pressure gradient between the SH and the Aleutian Low, a gradient which critically impacts EAWM variability. This difference series, based on tree-ring reconstructions of the SH and the North Pacific Index (NPI) over the past 400 years, shows that the weakening of this gradient in recent decades has not been unusual in a long-term context. Correlations between the SH series and a tree-ring reconstruction of the El Nino-Southern Oscillation (ENSO) suggest a variable tropical-higher latitude teleconnection.