1,721,101 research outputs found
The 9 October 1963 Vajont Catastrophe from the Point of View of the WWSSN-LP Recordings of the TRI-117 Station, Trieste, Italy
Full text linkIn this study, we analyze the seismic signal generated by the 1963 Vajont catastrophic landslide recorded at the Worldwide Standardized Seismographic Station Network- Long Period station of Trieste (Italy). The landslide (nearly 260–270 million m3) invaded an artificial reservoir designed for electrical production, and generated a 220 m high wave that flowed over the dam and claimed the lives of approximately 2000 people. The original seismograms have been digitized and analyzed using time–frequency tools and numerical simulations. The results indicate that a seismic signal comparable to that generated by an Ms 3.7 earthquake was generated by the landslide. Furthermore, the calculatednearly2×1014 Joffrictionalenergy,consideringtheknownparameterofthe mass movement, is compatible with a friction coefficient of 0.29, in excellent agreement with the values from previous studies. The seismic efficiency that we calculate (1:12 × 10−4 –4:45 × 10−4 ), also taking into account available data on the landslide, is within the range of values previously noted in literature. Finally, via the numerical sim- ulations and adopting an ad hoc crustal model for the area, the origin time of the event is estimated at 21 hr 41 min 42 s UTC. The results confirm the importance of the re-analy- sis of analog seismograms with modern tools within a multihazard context
Could a Decentralized Onsite Earthquake Early Warning System Help in Mitigating Seismic Risk in Northeastern Italy? The Case of the 1976 Ms 6.5 Friuli Earthquake
Full text linkIn May 1976, a devastating earthquake of magnitude Ms 6.5 occurred in Friuli, Italy,
resulting in 976 deaths, 2000 injured, and 60,000 homeless. It is notable that, at the time
of the earthquake, only one station was installed in the affected region. The resulting
lack of information, combined with a dearth of mitigation planning for responding to
such events, lead to a clear picture of the impact of the disaster being available only
after a few days.
This region is now covered by nearly 100 seismological and strong-motion stations
operating in real time. Furthermore, 30 average-cost strong-motion stations have been
recently added, with the goals of improving the density of real-time ground-motion
observations and measuring the level of shaking recorded at selected buildings. The
final goal is to allow rapid impact estimations to be made to improve the response
of civil protection authorities. Today, considering the higher density seismological net-
work, new efforts in terms of the implementation and testing of earthquake early
warning systems as a possible tool for mitigating seismic risk are certainly worthwhile.
In this article, we show the results obtained by analyzing in playback and using an
algorithm for decentralized onsite earthquake early warning, broadband synthetic
strong-motion data calculated at 18 of the stations installed in the region, while con-
sidering the magnitude and location of the 1976 Friuli earthquake. The analysis shows
that the anisotropy of the lead times is related not only to the finite nature of the source
but also to the slip distribution. A reduction of 10% of injured persons appears to be
possible if appropriate mitigating actions are employed, such as the development of
efficient automatic procedures that improve the safety of strategic industrial facilities
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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