January GEOLOGY Media Highlights

Boulder, CO, USA - Topics include: seismic threat to the Dalmation Islands; Caribbean coral tracks, long-term changes in hurricane activity, and the Atlantic Multidecadal Oscillation; fish DNA as a dating tool for topographic evolution; why terrestrial subduction is one-sided; evolution of atmospheric carbon dioxide on Snowball Earth; measuring magmatic water content and triggering of super-eruptions; modeling weathering profiles on Mars and implications for the planet's aqueous history; Barnes Ice Cap changes on Canada's Baffin Island; and blue diamond phosphorescence.

Eocene to present subduction of southern Adria mantle lithosphere beneath the Dinarides
Richard Bennett et al., Department of Geosciences, University of Arizona, Tucson, Arizona 85721-0077, USA. Pages 3-6.

Bennett et al. found that new geodetic data from the Dinarides mountains and Dalmatian islands in southern Croatia and Bosnia, indicate that the region is actively deforming. All indications are that the deformation is caused by seismically active thrust fault that will likely produce large earthquakes at some time in the future. Based on the long historical record of past earthquakes for the region, a future earthquake may be as large as M7 or more. A possible event of this magnitude poses a significant seismic threat to the Dalmatian islands (where the UNESCO heritage site Dubrovnik, also known as the "Pearl of the Adriatic," is located), as well as the possibility of a rare but dangerous tsunami in the Adriadic Sea.

Caribbean coral tracks Atlantic Multidecadal Oscillation and past hurricane activity
Steffen Hetzinger et al., Department of Chemical and Physical Sciences, University of Toronto at Mississauga, 3359 Mississauga Road N, South Building, Room 3007E, Mississauga, Ontario L5L 1C6, Canada. Pages 11-14.

Improved knowledge of long-term changes in hurricanes is important because the population of coastal areas affected directly by landfalls of major hurricanes is increasing.There is currently much debate about whether or not global warming has contributed to the strong hurricane activity observed during the last decade. The restricted length of the reliable instrumental record limits the detection of possible long-term changes in hurricane activity, which naturally exhibits strong multidecadal variations that are associated with the Atlantic Multidecadal Oscillation (AMO). Hetzinger et al. present the first marine record that clearly captures the AMO signal and multidecadal variations in North Atlantic hurricane activity. They obtained a climate record from a brain coral, found in the genesis region of Atlantic hurricanes, that sensitively records variations in seawater oxygen isotopes that are linked to precipitation and sea-surface temperature (SST) over the last century. As multidecadal SST variations in this region are closely related to the AMO, this study raises new possibilities to expand limited observations and gain new insights into the mechanisms of multidecadal climate variations and long-term changes in hurricane behavior.