Seismic measurements to reveal short-term variations in the elastic properties of the Earth crust

Since the late the late ’60s-early ’70s era seismologists started developed theories that included variations of the elastic property of the Earth crust and the state of stress and its evolution crust prior to the occurrence of a large earthquake. Among the others the theory of the dilatancy (Scholz et al., 1973): when a rock is subject to stress, the rock grains are shifted generating micro-cracks, thus the rock itself increases its volume. Inside the fractured rock, fluid saturation and pore pressure play an important role in earthquake nucleation, by modulating the effective stress. Thus measuring the variations of wave speed and of anisotropic parameter in time can be highly informative on how the stress leading to a major fault failure builds up. In 80s and 90s such kind of research on earthquake precursor slowed down and the priority was given to seismic hazard and ground motions studies, which are very important since these are the basis for the building codes in many countries. Today we have dense and sophisticated seismic networks to measure wave-fields characteristics: we archive continuous waveform data recorded at three components broad-band seismometers, we almost routinely obtain high resolution earthquake locations. Therefore we are ready to start to systematically look at seismic-wave propagation properties to possibly reveal short-term variations in the elastic properties of the Earth crust. One seismological quantity which, since the ‘70s, is recognized to be diagnostic of the level of fracturation and/or of the pore pressure in the rock, hence of its state of stress, is the ratio between the compressional (P-wave) and the shear (S-wave) seismic velocities, the Vp/Vs (Nur, 1972; Kisslinger and Engdahl, 1973). Variations of this ratio have been recently observed and measured during the preparatory phase of a major earthquake (Lucente et al. 2010). In active fault areas and volcanoes, tectonic stress variation influences fracture field orientation and fluid migration processes, whose evolution with time can be monitored through the measurement of the anisotropic pa- rameters (Miller and Savage, 2001; Piccinini et al., 2006). Through the study of S waves anisotropy it is therefore potentially possible to measure the presence, migration and state of the fluid in the rock traveled by seismic waves, thus providing a valuable route to understanding the seismogenic phenomena and their precursors (Crampin & Gao, 2010). In terms of determination of Earth crust elastic properties, recent studies (Brenguier et al., 2008; Chen et al., 2010; Zaccarelli et al., 2011) have shown how it is possible to estimate the relative variations in the wave speed through the analysis of the crosscorrelation of ambient seismic noise. In this paper we analyze in detail two seismological methods dealing with shear wave splitting and seismic noise cross correlation: a short historical review, their theoretical bases, the problems, learnings, limitations and perspec- tives. Moreover we discuss the results of these methods already applied on the data recorded in the L’Aquila region, before and after the destructive earthquake of April 6th 2009, represent their self an interesting case study

Passive seismology and deep structure in central Italy

n the last decade temporary teleseismic transects have become a powerful tool for investigating the crustal and upper mantle structure. In order to gain a clearer picture of the lithosphere-asthenosphere structure in peninsular Italy, between 1994 and 1996, we have deployed three teleseismic transects in northern, central, and southern Apennines, in the framework of the project GeoModAp (European Community contract EV5V-CT94–0464). Some hundreds of teleseisms were recorded at each deployment which lasted between 3 and 4 months. Although many analyses are still in progress, the availability of this high quality data allowed us to refine tomographic images of the lithosphere-asthenosphere structure with an improved resolution in the northern and central Apennines, and to study the deformation of the upper mantle looking at seismic anisotropy through shear-wave splitting analysis. Also, a study of the depth and geometry of the Moho through the receiver function technique is in progress. Tomographic results from the northernmost 1994 and the central 1995 teleseismic experiments confirm that a high-velocity anomaly (HVA) does exist in the upper 200–250 km and is confined to the northern Apenninic arc. This HVA, already interpreted as a fragment of subducted lithosphere is better defined by the new temporary data, compared to previous works, based only on data from permanent stations. No clear high-velocity anomalies are detected in the upper 250 km below the central Apennines, suggesting either a slab window due to a detachment below southern peninsular Italy, or a thinner, perhaps continental slab of Adriatic lithosphere not detectable by standard tomography. We found clear evidence of seismic anisotropy in the uppermost mantle, related to the main tectonic processes which affected the studied regions, either NE–SW compressional deformation of the lithosphere beneath the mountain belt, or arc-parallel asthenospheric flow (both giving NW–SE fast polarization direction), and successive extensional deformation ( E–W trending) in the back-arc basin of northern Tyrrhenian and Tuscany. Preliminary results of receiver function studies in the northern Apennines show that the Moho depth is well defined in the Tyrrhenian and Adriatic regions while its geometry underneath the mountain belt is not yet well constrained, due to the observed high complexity.Published479-4934T. Sismicità dell'ItaliaJCR Journa

Bollettino Sismico Italiano: gennaio - aprile 2015

Nel primo quadrimestre 2015 si sono verificati 5 eventi di magnitudo superiore a 4: il 23 gennaio un Mw 4.3 è stato localizzato tra le province di Bologna e Prato, seguito da una sequenza di alcune centinaia di eventi; il 6 febbraio un Mw 4.7 al largo delle Isole Eolie, ad oltre 270 km di profondità; il 28 febbraio un Mw 4.1 nella Piana del Fucino; il 15 aprile un evento di magnitudo Mw 4.3 nel Mar Tirreno, al largo della costa calabra occidentale, ad una profondità di oltre 250 km e il 24 aprile un terremoto di magnitudo ML 4.0 tra le province di Ravenna e Forlì-Cesena,seguito da una sequenza di oltre 80 repliche.Istituto Nazionale di Geofisica e Vulcanologia e Dipartimento Protezione CivilePublished4IT. Banche dat

Bollettino Sismico Italiano: settembre - dicembre 2015

Nel terzo quadrimestre 2015 si sono verificati 5 terremoti con M>4 nel territorio Italiano. In particolare il 14 ed il 16 ottobre si sono verificati due eventi profondi del basso Tirreno il primo con M=4.2 a 300 km di profondità, il secondo con M=4.4 a circa 250 km di profondità. Due terremoti M4.2 e M4.4 sono avvenuti il 6 dicembre nel Mar Adriatico a nord delle Isole Tremiti. Associati a questi si sono verificati alcuni eventi di magnitudo sopra a 3.5: si è trattata di una vera e propria sequenza sismica durata pochi giorni. L’ultimo evento di magnitudo superiore a 4 si è verificato a NE di Palermo nel basso Tirreno il 20 dicembre con una M=4.2. E’ infine da segnalare un terremoto con M = 4.8 che si è verificato il 1 Novembre in Slovenia, al confine con la Croazia.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublished4IT. Banche dat

Bollettino Sismico Italiano: maggio - agosto 2015

Nel secondo quadrimestre 2015 si sono verificati 7 eventi di magnitudo superiore a 4: il 9 maggio un evento di ML 4.5 è stato localizzato nel basso Tirreno ad una profondità di circa 217 km; l’11 maggio un terremoto di Mw 4.4 nel Mar Ionio a circa 47 km di profondità; il 29 maggio un Mw 4.2 nel Mar Adriatico di fronte a San Benedetto del Tronto; il 2 agosto un evento di magnitudo ML4.0 nel Mar Tirreno, al largo della costa calabra occidentale, ad una profondità di circa 247 km e il 3 agosto un terremoto di magnitudo ML 4.0 tra le province di Cosenza e Catanzaro a sud della Sila, seguito da una sequenza di oltre 80 repliche di piccola magnitudo. L’8 agosto 2015 si è verificato un terremoto di ML 4.1 alle Isole Eolie, ed infine il 29 agosto un evento di Mw 4.0 vicino al confine della Slovenia con il Friuli Venezia Giulia, seguito da una sequenza sismica che è continuata anche dopo il 31 agosto.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublished4IT. Banche dat

Bollettino Sismico Italiano: maggio - agosto 2016

Il 24 agosto 2016 un terremoto di magnitudo 6.0 ha dato inizio ad una sequenza sismica in Italia centrale, che ha generato decine di migliaia di eventi sismici. Per l’analisi e revisione di questa sequenza si rimanda ad un uscita speciale del BSI prevista per fine 2017(S_BSI_CI). In questo quadrimestre e nel successivo gli eventi nella zona della sequenza sono quelli localizzati nella sala di sorveglianza. Solo gli eventi con M>= 3.5, e pochi altri (vedi Marchetti et al. Annals of Geophys. DOI: 10.4401/ag6116) sono stati rivisti dal BSI.Nel secondo quadrimestre 2016 si sono verificati sedici eventi di magnitudo superiore a 4.0 (ML) rivisti dagli analisti del BSI uno vicino alle coste tunisine quindi fuori dal territorio nazionale; l’evento di Mw 4.1 che è avvenuto il 30 maggio in provincia di Terni vicino al Lago di Bolsena (lat=42.7, lon=11.98 ad una profondità di 8 km) e 14 eventi nella zona della sequenza nell’ultima settimana del quadrimestre: il 24 agosto 2016 si è verificato l’evento di magnitudo ML=6.0 (Mw=6.0) che ha iniziato una sequenza sismica per la quale sono stati localizzati decine di migliaia di terremoti e che alla fine di ottobre 2016 ha generato eventi persino più forti (fino a Mw=6.5) della prima scossa.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublished4IT. Banche dat

Beta-Blocker Use in Older Hospitalized Patients Affected by Heart Failure and Chronic Obstructive Pulmonary Disease: An Italian Survey From the REPOSI Register

Beta (β)-blockers (BB) are useful in reducing morbidity and mortality in patients with heart failure (HF) and concomitant chronic obstructive pulmonary disease (COPD). Nevertheless, the use of BBs could induce bronchoconstriction due to β2-blockade. For this reason, both the ESC and GOLD guidelines strongly suggest the use of selective β1-BB in patients with HF and COPD. However, low adherence to guidelines was observed in multiple clinical settings. The aim of the study was to investigate the BBs use in older patients affected by HF and COPD, recorded in the REPOSI register. Of 942 patients affected by HF, 47.1% were treated with BBs. The use of BBs was significantly lower in patients with HF and COPD than in patients affected by HF alone, both at admission and at discharge (admission, 36.9% vs. 51.3%; discharge, 38.0% vs. 51.7%). In addition, no further BB users were found at discharge. The probability to being treated with a BB was significantly lower in patients with HF also affected by COPD (adj. OR, 95% CI: 0.50, 0.37-0.67), while the diagnosis of COPD was not associated with the choice of selective β1-BB (adj. OR, 95% CI: 1.33, 0.76-2.34). Despite clear recommendations by clinical guidelines, a significant underuse of BBs was also observed after hospital discharge. In COPD affected patients, physicians unreasonably reject BBs use, rather than choosing a β1-BB. The expected improvement of the BB prescriptions after hospitalization was not observed. A multidisciplinary approach among hospital physicians, general practitioners, and pharmacologists should be carried out for better drug management and adherence to guideline recommendations

Clinical features and outcomes of elderly hospitalised patients with chronic obstructive pulmonary disease, heart failure or both

Background and objective: Chronic obstructive pulmonary disease (COPD) and heart failure (HF) mutually increase the risk of being present in the same patient, especially if older. Whether or not this coexistence may be associated with a worse prognosis is debated. Therefore, employing data derived from the REPOSI register, we evaluated the clinical features and outcomes in a population of elderly patients admitted to internal medicine wards and having COPD, HF or COPD + HF. Methods: We measured socio-demographic and anthropometric characteristics, severity and prevalence of comorbidities, clinical and laboratory features during hospitalization, mood disorders, functional independence, drug prescriptions and discharge destination. The primary study outcome was the risk of death. Results: We considered 2,343 elderly hospitalized patients (median age 81 years), of whom 1,154 (49%) had COPD, 813 (35%) HF, and 376 (16%) COPD + HF. Patients with COPD + HF had different characteristics than those with COPD or HF, such as a higher prevalence of previous hospitalizations, comorbidities (especially chronic kidney disease), higher respiratory rate at admission and number of prescribed drugs. Patients with COPD + HF (hazard ratio HR 1.74, 95% confidence intervals CI 1.16-2.61) and patients with dementia (HR 1.75, 95% CI 1.06-2.90) had a higher risk of death at one year. The Kaplan-Meier curves showed a higher mortality risk in the group of patients with COPD + HF for all causes (p = 0.010), respiratory causes (p = 0.006), cardiovascular causes (p = 0.046) and respiratory plus cardiovascular causes (p = 0.009). Conclusion: In this real-life cohort of hospitalized elderly patients, the coexistence of COPD and HF significantly worsened prognosis at one year. This finding may help to better define the care needs of this population

The “Diabetes Comorbidome”: A Different Way for Health Professionals to Approach the Comorbidity Burden of Diabetes

(1) Background: The disease burden related to diabetes is increasing greatly, particularly in older subjects. A more comprehensive approach towards the assessment and management of diabetes’ comorbidities is necessary. The aim of this study was to implement our previous data identifying and representing the prevalence of the comorbidities, their association with mortality, and the strength of their relationship in hospitalized elderly patients with diabetes, developing, at the same time, a new graphic representation model of the comorbidome called “Diabetes Comorbidome”. (2) Methods: Data were collected from the RePoSi register. Comorbidities, socio-demographic data, severity and comorbidity indexes (Cumulative Illness rating Scale CIRS-SI and CIRS-CI), and functional status (Barthel Index), were recorded. Mortality rates were assessed in hospital and 3 and 12 months after discharge. (3) Results: Of the 4714 hospitalized elderly patients, 1378 had diabetes. The comorbidities distribution showed that arterial hypertension (57.1%), ischemic heart disease (31.4%), chronic renal failure (28.8%), atrial fibrillation (25.6%), and COPD (22.7%), were the more frequent in subjects with diabetes. The graphic comorbidome showed that the strongest predictors of death at in hospital and at the 3-month follow-up were dementia and cancer. At the 1-year follow-up, cancer was the first comorbidity independently associated with mortality. (4) Conclusions: The “Diabetes Comorbidome” represents the perfect instrument for determining the prevalence of comorbidities and the strength of their relationship with risk of death, as well as the need for an effective treatment for improving clinical outcomes

Antidiabetic Drug Prescription Pattern in Hospitalized Older Patients with Diabetes

Objective: To describe the prescription pattern of antidiabetic and cardiovascular drugs in a cohort of hospitalized older patients with diabetes. Methods: Patients with diabetes aged 65 years or older hospitalized in internal medicine and/or geriatric wards throughout Italy and enrolled in the REPOSI (REgistro POliterapuie SIMI—Società Italiana di Medicina Interna) registry from 2010 to 2019 and discharged alive were included. Results: Among 1703 patients with diabetes, 1433 (84.2%) were on treatment with at least one antidiabetic drug at hospital admission, mainly prescribed as monotherapy with insulin (28.3%) or metformin (19.2%). The proportion of treated patients decreased at discharge (N = 1309, 76.9%), with a significant reduction over time. Among those prescribed, the proportion of those with insulin alone increased over time (p = 0.0066), while the proportion of those prescribed sulfonylureas decreased (p < 0.0001). Among patients receiving antidiabetic therapy at discharge, 1063 (81.2%) were also prescribed cardiovascular drugs, mainly with an antihypertensive drug alone or in combination (N = 777, 73.1%). Conclusion: The management of older patients with diabetes in a hospital setting is often sub-optimal, as shown by the increasing trend in insulin at discharge, even if an overall improvement has been highlighted by the prevalent decrease in sulfonylureas prescription