Gerald P Roberts

We demonstrate a synchronous correlation technique to determine the chronology of Quaternary palaeoshorelines to test proposed relationships between tectonics, climate and sea-level change. The elevations of marine palaeoshorelines in Calabria around the active Vibo normal fault have been measured from TIN DEM 10 m data and fieldwork and correlated with global sea-level curves. A synchronous correlation method and new U/Th dates are used to ascertain how the slip-rate on the fault relates to uplift rates across the region. Regional uplift, possibly associated with subduction along the Calabrian trench or due to the cumulative effect of closely-spaced active normal faults, is rapid enough to uplift even the hangingwall of the Vibo normal fault; the actual value for the rate of background uplift can only be ascertained once the rate of slip on the Vibo fault is subtracted. Synchronous correlation of multiple palaeoshorelines sampled along 29 elevation profiles with global sea-levels shows that the resultant uplift rate (background uplift minus local hangingwall subsidence) is constant through time from 0 to 340 ka, and not fluctuating by a factor of 4 as previously suggested. The uplift rate increases from 0.4 mm/yr at the centre of the hangingwall of the fault to 1.75 mm/yr in the hangingwall in the vicinity of the fault tip. Palaeoshorelines can be traced from the hangingwall to the footwall around the fault tip and hence correlated across the fault. The throw-rate on the fault averaged over 340 ka decreases from a maximum at the centre of the fault (1 mm/yr) to zero at the tip. This gradient in throw-rate explains the spatial variation in resultant uplift rates along the fault. We interpret the 1.75 mm/yr resultant uplift rate at and beyond the fault tip as the signature of a regional uplift, presumably related to subduction, although we cannot exclude the possibility that other local faults influence this uplift; the lower uplift rates in the hangingwall of the fault are due to interaction between “regional” uplift and subsidence associated with the local active normal faulting. We discuss (a) how our synchronous correlation technique should trigger a re-appraisal of palaeoshoreline chronologies worldwide, and (b) the implications for the tectonics and seismic hazard of Calabria, suggesting that perturbations in the uplift-rate field are a key criterion to map the locations of active faults, their deformation rates, and hence seismic hazard above subduction zones.

The 2009 Mw=6.3 L' Aquila earthquake in central Italy despite its moderate magnitude caused significant loss of life and damages, producing the highest death toll in the E.U. since the 1980 Mw=6.9 Irpinia event and the highest economic cost since the 1999 Ms=5.9 Athens earthquake. It is now recognized that such events pose a high risk in most extensional settings, such as Europe at large due both to its high rate of occurrence and proximity to human habitation, forming a typical case study scenario. The deformation pattern of the 6th and 7th of April 2009 Mw=6.3 and Mw=5.6 earthquakes in L' Aquila is revealed by DInSAR analysis and compared with earthquake environmental effects. The DInSAR predicted fault surface ruptures coincide with localities where surface ruptures have been observed in the field, confirming that the ruptures observed near Paganica village are indeed primary. These ruptures are almost one order of magnitude lower than the ruptures that have been produced...

We have developed Crossint as an interactive tool for the analysis of normal fault slip rates, using terrestrial laser scan datasets. The long-term slip rate of active normal faults is a key parameter in hazard mapping and planning, as earthquake recurrence intervals decrease (the risk increases) as slip rates increase. Normal fault slip rates measured over geological time-scales are conventionally defined from surface offset surveys of a limited number of sites along a fault, using survey methods such as total station and differential GPS. We present an alternative method of slip rate analysis using a high resolution terrestrial laser scan (TLS) dataset from the Campo Felice fault in the Apennines, central Italy. Individually selected TLS derived cross sections for numerous sites along the length of the fault were interpreted using Crossint to produce a reliable assessment of surface offset and slip rate. Geomorphic features such as gullies, alluvial fans and rotational land slips ...

This study compares continual assessment data, intake numbers, retention numbers and final examination grades of a mixed cohort of face-to-face and distance learners against similar data from previous years where e-learning materials were not used in order to test whether e-...

The Sparta Fault system is a major structure approximately 64 km long that bounds the eastern flank of the Taygetos Mountain front (2.407 m) and shapes the present-day Sparta basin. It was activated in 464 BC, devastating the city of Sparta. This fault is examined and described in terms of its geometry, segmentation, drainage pattern and postglacial throw, emphasizing how these parameters vary along strike. Qualitative analysis of long profile catchments shows a significant difference in longitudinal convexity between ...

This paper documents evidence of surface faulting associated with the 6 April 2009 moderate-sized earthquake (ML 5.8, M w 6.3) in the central Apennines of Italy, which caused major damage to the town of L'Aquila and its surroundings. Coseismic surface ruptures were mapped for a minimum distance of 2.6 km along the Paganica fault, a fault still poorly investigated relative to the other active faults nearby, which bound much wider range fronts. Surface rupture length (SRL) and maximum displacement parameters (2.6 km minimum ...

We use InSAR and body-wave seismology to determine independent source parameters for the 6th April 2009 Mw 6.3 L'Aquila earthquake and confirm that the earthquake ruptured a SW-dipping normal fault with∼ 0.6–0.8 m slip. The causative Paganica fault had been neglected relative to other nearby range-frontal faults, partly because it has a subdued geomorphological expression in comparison with these faults. The L'Aquila earthquake occurred in an area with a marked seismic deficit relative to geodetically determined strain ...

We test interactions between sea-level change, climate and tectonic activity using a synchronous correlation method to refine and define ages of dated and undated Quaternary marine terraces sequences and their chronology. We mapped and measured the inner edge elevations of marine terraces, tectonically deformed by a Quaternary active normal fault, correlating them with global sea-level curves. The uplift process affecting Calabria is rapid enough to raise parts the hangingwall of the investigated active Vibo Fault above sea-level, so we can correlate terraces across the fault. We suggest that the uplift rates at individual locations along the fault are (a) either enhanced by footwall uplift locations or counteracted by hangingwall subsidence with values decreasing towards the SW fault tip, and (b) are constant through time. We stress that our synchronous correlation method should produce a review of marine terraces investigations worldwide, and that uplift rate perturbations are a key condition to map active faults locations, their deformation rates and the associated seismic hazard above subduction zones.