Maria D'Amico

NESS1: A Worldwide Collection of Strong‐Motion Data to Investigate Near‐Source Effects

The availability of high-quality waveforms recorded in epicentral areas of moderate-to-strong earthquakes is a key factor for investigating ground-motion characteristics close to the seismic source. In this study, near-source strong-motion waveforms (named NESS1) were collected from worldwide public archives with the aim of building a flat file of high-quality metadata and intensity measures (IMs) of engineering interest. Particular attention was paid to the retrieval of reliable information about event sources, such as geometries and rupture mechanisms that are necessary to model near-source effects for engineering seismology and earthquake engineering applications. The accelerometric records are manually and uniformly processed, and the associated information is fully traceable. NESS1 consists of about 800 three-component waveforms relative to 700 accelerometric stations, caused by 74 events with moment magnitude larger than 5.5 and hypocentral depth shallower than 40 km, with Joyner–Boore distance up to 140 km. Ground-motion data were selected to have a maximum sourceto-site distance within one fault length, defined through seismological scaling relations. About 40 records exhibit peak acceleration or peak velocity exceeding 1g or 120 cm=s, and they represent some of the largest ground motion ever recorded. Evidence of near-source effects was recognized in the NESS1 dataset, such as velocity pulses, large vertical ground motions, directional and hanging-wall amplifications and fling step. In particular, around 30% of the records was found to exhibit pulse-like characteristics that are possibly due to forward rupture directivity. Electronic Supplement: Table listing the main features of the selected events, including the references of fault geometry parameters and Figures showing further metadata and intensity measures distributions of the NESS1 flat file.

Location of the ancient Tindari harbour from geoarchaeological investigations (NE Sicily)

Abstract In the Greek and Roman periods, the fortified town of Tindaris military and trading importance combined with its strategic location in north-east Sicily allowed it to control traffic on the Tyrrhenian Sea for many centuries. Historical sources (Polybius, Cicero, Livy and Appian) testify to the flourishing maritime activity of the ancient town, but do not supply any information on the location, size or configuration of its harbour. Because a town as important as Tindari must have had a landing place for ships, we examined new sources of information with the aim of identifying its location. Historiographical and archaeological surveys produced evidence of a well-organised harbour. Geomorphological investigations, performed along the Tindari Promontory, identified Holocene uplifted and submerged notches indicating past sea level changes. Furthermore, it was found that in the last four centuries the combined actions of marine and fluvial dynamics had produced a progressive filling of the Oliveri lowland and a progradation of the shoreline, which was responsible for the burial of ancient buildings. The palaeotopographic reconstruction of the Tindari Cape Promontory and Oliveri coastal plain in the 4th century BC shows a safe landing place south-east of the Tindari Cape that was suitably protected from prevailing winds.