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Coda-Q is used to estimate the attenuation and scattering properties of the Earth. So far focus has been on earthquake data at frequencies above 1 Hz, as the high noise level in the first and second microseismic peak, and possibly lower scattering coefficient, hinder stable measurements at lower frequencies. In this work, we measure and map coda-Q in the period bands 2.5-5 s, 5-10 s and 10-20 s in the greater Alpine region using noise cross-correlations between station pairs, based on data from permanent seismic stations and from the temporary AlpArray experiment. The observed coda-Q for short interstation distances is independent of azimuth so there is no indication of influence of the directivity of the incoming noise field on our measurements. In the 2.5-5 s and 5-10 s period bands, our measurements are self-consistent, and we observe stable geographic patterns of low and high coda-Q in the period bands 2.5-5 s and 5-10 s. In the period band 10-20 s, the dispersion of our measurements increases and geographic patterns become speculative. The coda-Q maps show that major features are observed with high resolution, with a very good geographical resolution of for example low coda-Q in the Po Plain. There is a sharp contrast between the Po Plain and the Alps and Apennines where coda-Q is high, with the exception a small area in the Swiss Alps which may be contaminated by the low coda-Q of the Po Plain. The coda of the correlations is too short to make independent measurements at different times within the coda, so we cannot distinguish between intrinsic and scattering Q. Measurements on more severely selected data sets and longer time-series result in identical geographical patterns but lower numerical values. Therefore, high coda-Q values may be overestimated, but the geographic distribution between high and low coda-Q areas is respected. Our results demonstrate that noise correlations are a promising tool for extending coda-Q measurements to frequencies lower than those analysed with earthquake data.

Multiferroics are materials where magnetic and ferroelectric order coexist. This opens a possibility of control of magnetic order by both magnetic and electric field which makes these materials potentially technologically important. CuO is quasi-one-dimensional S=1/2 system which is also multiferroic. CuO has three magnetically ordered phases: below T_N1=213 K it is collinear antiferromagnet (AFM1 phase), between T_N1 < T < T_N2 (T_N2 = 229.3 K) it is incommensurable spiral antiferromagnet(AFM2 phase) and also multiferroic, and between T_N2 < T < T_N3 (T_N3 = 230 K) it is incommensurable collinear antiferromagnet (AFM3 phase). Theoretical calculations have shown that CuO could be multiferroic at room temperature under high pressures. Multiferroic state of CuO is still widely studied and not completely understood. Anisotropic interactions, i.e. Dzayloshinskii-Moriya, is expected to play an important role in multiferroic phase [5]. Measuring magnetic anisotropy is thus crucial for understanding of mechanism responsible for multiferroicity in CuO. Macroscopic anisotropy of CuO is studied with torque magnetometry in low magnetic fields in the temperature range 4.2 K – 300 K. All three magnetic phase transitions are observed in torque

Herbertsmitit je mineral u kojem je realizirana frustrirana kagome magnetska rešetka i jedan je od materijala u kojima je potvrđeno postojanje egzotičnog stanja kvantne spinske tekućine. U herbertsmititu su spinovi S=1/2 bakrovog iona Cu2+ smješteni na 2D kagome rešetci te su interakcije opisane izotropnim antiferomagnetskim Heisenbergovim hamiltonijanom. Medđutim, kao i u svakom realnom materijalu, i u herbertsmititu postoje dodatne perturbacije poput anizotropije nterakcija između spinova gdje se ističe anizotropna Dzyaloshinskii-Moriya interakcija. Možda najvažnija perturbacija u ovom materijalu je prisustvo velikog broja nečistoća. Ioni bakra mještaju se u herbertsmititu na mjesta cinka u slojevima između kagome ravnina, no istovremeno postoji mogućnost smještanja iona cinka na mjesto bakra u kagome sloju, što narušava savršenost kagome rešetke te će imati ujecaja na osnovno tanje kvantne spinske tekućine. Komplementarnim mjerenjima magnetskog momenta sile i elektronske spinske rezonancije nedavno smo pokazali da u herbertsmititu postoje dvije vrste defekata od kojih je jedna puno jače vezana za pinove u kagome rešetci nego druga. Magnetski moment sile osjetljiv je na makroskopsku magnetsku anizotropiju te globalnu simetriju. Naši rezultati pokazuju da pri niskim temperaturama dolazi do sniženja globalne simetrije u herbertsmititu što može imati utjecaj na odabir osnovnog stanja u ovom materijalu. Ovaj rad djelomično je financiran projektom Hrvatske zaklade za znanost HRZZ UIP-2014-09-9775 te bilateralnim HR-SLO projektom "Ključna uloga magnetske anizotropije u niskodimenzionalnim spinskim sustavima".

A review of the recent achievements of the innovative neo-deterministic approach for seismic hazard assessment through realistic earthquake scenarios has been performed. The procedure provides strong ground motion parameters for the purpose of earthquake engineering, based on the deterministic seismic wave propagation modelling at different scales— regional, national and metropolitan. The main advantage of this neo-deterministic procedure is the simultaneous treatment of the contribution of the earthquake source and seismic wave propagation media to the strong motion at the target site/region, as required by basic physical principles. The neo-deterministic seismic microzonation procedure has been successfully applied to numerous metropolitan areas all over the world in the framework of several international projects. In this study some examples focused on CEI region concerning both regional seismic hazard assessment and seismic microzonation of the selected metropolitan areas are shown.

Il progetto è orientato al problema della prevenzione dei disastri: valutazione, prevenzione e ubicazione del rischio, in connessione con l’attività sismica e le vibrazioni artificiali. La definizione realistica della sollecitazione sismica è stata ottenuta col calcolo di un ampio insieme di serie temporali (sismogrammi sintetici) e relative informazioni spettrali, corrispondenti ai possibili scenari sismotettonici. La tecnica innovativa di modellazione, che costituisce il filo conduttore dell’intero progetto, prende in considerazione l’origine delle onde sismiche, la loro propagazione e gli effetti locali nel luogo di interesse. Ciò è stato realizzato utilizzando i principi fisici della generazione e propagazione delle onde nei mezzi anelastici, evitando di rifarsi ad un approccio convolutivo che si è dimostrato del tutto irrealistico, soprattutto in caso di strutture geologiche complesse, che sono poi le più interessanti dal punto di vista pratico. Molte tecniche, che sono state proposte per stimare empiricamente gli effetti locali tramite la convoluzione di osservazioni con segnali, calcolati in corrispodenza di modelli semplificati, forniscono informazioni attendibili sulla risposta sismica del sito a fasi sismiche non interferenti. Essi sono inadeguati nella maggior parte dei casi reali, dove la sequenza sismica è formata invece da diverse onde interferenti. La disponibilità di simulazioni numeriche realistiche ha reso possibile una stima attendibile dell’effetto di amplificazione locale, persino nel caso di strutture geologiche complesse, quando sono disponibili i parametri geotecnici, litologici e geofisici, i dati topografici, tettonici, storici e paleosismologici, nonche’ i modelli sismotettonici. La modellazione realistica dei movimenti tellurici è un punto fondamentale nella preparazione di scenari di scuotimento del suolo (groundshaking) che rappresentano un valido ed economico strumento per la microzonazione sismica. Tale conoscenza è facilmente utilizzabile negli ambiti dell’ingegneria civile per i progetti di nuove costruzioni antisismiche e per migliorare le strutture già esistenti, ed inoltre rappresenta un ottimo strumento nell’ambito dei servizi di prevenzione della protezione civile. Vene Qui presentata una selezione dei principali risultati ottenuti nelle città di: Algeri, Pechino, Bucarest, Cairo, Debrecen, Delhi, Napoli, Roma, Russe, Santiago de Cuba, Sofia, Salonicco e Zagabria.

A hybrid technique consisting of modal summation and subsequent ®nite differences modelling is applied for the computation of synthetic accelerograms along a pro®le crossing the city of Zagreb, the capital of Croatia. Assuming the source geometry is known, the ampli®cation properties of the underlying soil may be determined by comparison of synthetics and their response spectra computed for a bedrock model with the ones obtained under the assumption of a realistic laterally varying local model. The peak ground acceleration is larger by a factor of up to 3.5 than the value obtained for the bedrock model. The ampli®cation of the response spectra is most prominent for frequencies below 2 Hz, and increases sharply to the SW from the mapped fault running through the centre of the city. q 2002 Published by Elsevier Science Ltd.

During a three year-period, the participants of a NATO Science for Peace project performed ambient noise measurements inside buildings in four European countries. This paper reports the results relevant to reinforced concrete (RC) buildings with height in the range 1-20 floors. The total number of such buildings surveyed is 244. The most striking feature is the similarity of the height-period relationships in the four countries, which allowed the treatment of the all measurements as a single database. We found no significant correlation with other variables, and calculated a regression that is very similar to other empirical height-period relationships and quite different from code provisions and theoretical models.

Report submitted to the International Association of Seismology and Physics of the Earth’s Interior of the International Union of Geodesy and Geophysics