Stress changes, focal mechanisms, and earthquake scaling laws for the 2000 dike at Miyakejima (Japan)

open4siFaulting processes in volcanic areas result from a complex interaction of pressurized fluid‐filled cracks and conduits with the host rock and local and regional tectonic setting. Often, volcanic seismicity is difficult to decipher in terms of the physical processes involved, and there is a need for models relating the mechanics of volcanic sources to observations. Here we use focal mechanism data of the energetic swarm induced by the 2000 dike intrusion at Miyakejima (Izu Archipelago, Japan), to study the relation between the 3‐D dike‐induced stresses and the characteristics of the seismicity. We perform a clustering analysis on the focal mechanism (FM) solutions and relate them to the dike stress field and to the scaling relationships of the earthquakes. We find that the strike and rake angles of the FMs are strongly correlated and cluster on bands in a strike‐rake plot. We suggest that this is consistent with optimally oriented faults according to the expected pattern of Coulomb stress changes. We calculate the frequency‐size distribution of the clustered sets finding that focal mechanisms with a large strike‐slip component are consistent with the Gutenberg‐Richter relation with a b value of about 1. Conversely, events with large normal faulting components deviate from the Gutenberg‐Richter distribution with a marked roll‐off on its right‐hand tail, suggesting a lack of large‐magnitude events (Mw > 5.5). This may result from the interplay of the limited thickness and lower rock strength of the layer of rock above the dike, where normal faulting is expected, and lower stress levels linked to the faulting style and low confining pressure.Acknowledgments. Data to support this article are from the Japan Meteorological Agency (JMA) and Japan National Research Institute of Earth Science and Disaster Prevention (NIED) which are the only owners of the data. Any request of data should be addressed directly to those institutions. Focal mechanisms from 2004 are available online at http://www.hinet.bosai.go.jp/. L.P. and E.R. were funded by the European Union through the ERC Starting grant project CCMP‐POMPEI, grant 240583, and Med‐Suv ERC funded project. S.C. was funded by the MINE project by the German BMBF “Geotechnologien” grant BMBF03G0737. We thank the Japan Meteorological Agency and National Institute for Earth Science and Disaster Prevention for access to the catalogs of hypocenters and focal mechanisms. We thank Francesco Maccaferri, Sebastian Hainzl, and Camilla Cattania for the fruitful discussion which helped us to clarify some of the ideas discussed in the paper. The comments by two anonymous reviewers and Associate Editor helped in improving the manuscript. Figures from 1-6 and 8 were drawn with GMT [Wells and Coppersmith, 1994].openPassarelli, Luigi; Rivalta, Eleonora; Cesca, Simone; Aoki, YosukePassarelli, Luigi; Rivalta, Eleonora; Cesca, Simone; Aoki, Yosuk

Hyperbaric oxygen treatment of superficial soft tissue lesions in children with oncologic disease

This study aimed to assess the feasibility and results of hyperbaric oxygen therapy (HOT) as supportive treatment of lesions of superficial soft tissues in children with oncological diseases. This was a retrospective analysis and review of all records of children observed at the Pediatric Hematology-Oncology Department of the University of Padova and treated adjuvantly with HOT. Between 1996 and 2010, 12 patients (5 males and 7 females, median age 7 years, range 0.5–16) underwent HOT. The effectiveness of HOT varied according to the lesion treated. Ten out of 12 patients were cured. Efficacy was most questionable in 2 patients with skin graft and flaps at risk. Compliance to therapy was close to 100%. In just one case, HOT was interrupted for the appearance of local skin metastases close to the site of primary tumor. HOT showed itself to be safe and effective in most patients even those immunocompromised or critically ill

Massive earthquake swarm driven by magmatic intrusion at the Bransfield Strait, Antarctica

An earthquake swarm affected the Bransfield Strait, Antarctica, a unique rift basin in transition from intra-arc rifting to ocean spreading. The swarm, counting ~85,000 volcanotectonic earthquakes since August 2020, is located close to the Orca submarine volcano, previously considered inactive. Simultaneously, geodetic data reported up to ~11 cm northwestward displacement over King George Island. We use a broad variety of geophysical data and methods to reveal the complex migration of seismicity, accompanying the intrusion of 0.26-0.56 km³ of magma. Strike-slip earthquakes mark the intrusion at depth, while shallower normal faulting the ~20 km long lateral growth of a dike. Seismicity abruptly decreased after a Mw 6.0 earthquake, suggesting the magmatic dike lost pressure with the slipping of a large fault. A seafloor eruption is likely, but not confirmed by sea surface temperature anomalies. The unrest documents episodic magmatic intrusion in the Bransfield Strait, providing unique insights into active continental rifting

Aseismic transient driving the swarm-like seismic sequence in the Pollino range, Southern Italy

Tectonic earthquake swarms challenge our understanding of earthquake processes since it is difficult to link observations to the underlying physical mechanisms and to assess the hazard they pose. Transient forcing is thought to initiate and drive the spatio-temporal release of energy during swarms. The nature of the transient forcing may vary across sequences and range from aseismic creeping or transient slip to diffusion of pore pressure pulses to fluid redistribution and migration within the seismogenic crust. Distinguishing between such forcing mechanisms may be critical to reduce epistemic uncertainties in the assessment of hazard due to seismic swarms, because it can provide information on the frequency–magnitude distribution of the earthquakes (often deviating from the assumed Gutenberg–Richter relation) and on the expected source parameters influencing the ground motion (for example the stress drop). Here we study the ongoing Pollino range (Southern Italy) seismic swarm, a long-lasting seismic sequence with more than five thousand events recorded and located since October 2010. The two largest shocks (magnitude Mw = 4.2 and Mw = 5.1) are among the largest earthquakes ever recorded in an area which represents a seismic gap in the Italian historical earthquake catalogue. We investigate the geometrical, mechanical and statistical characteristics of the largest earthquakes and of the entire swarm. We calculate the focal mechanisms of the Ml > 3 events in the sequence and the transfer of Coulomb stress on nearby known faults and analyse the statistics of the earthquake catalogue. We find that only 25 per cent of the earthquakes in the sequence can be explained as aftershocks, and the remaining 75 per cent may be attributed to a transient forcing. The b-values change in time throughout the sequence, with low b-values correlated with the period of highest rate of activity and with the occurrence of the largest shock. In the light of recent studies on the palaeoseismic and historical activity in the Pollino area, we identify two scenarios consistent with the observations and our analysis: This and past seismic swarms may have been ‘passive’ features, with small fault patches failing on largely locked faults, or may have been accompanied by an ‘active’, largely aseismic, release of a large portion of the accumulated tectonic strain. Those scenarios have very different implications for the seismic hazard of the area

A model-based early warning system for runoff-generated debris-flow occurrence: Preliminary results

Early warning systems for debris flows are low cost measures for mitigating this kind of hazard. The early warning systems provide a timely alert for upcoming events in order to take protective measures, such as closing railways-roads, evacuating people from the threatened areas, and put rescue forces into readiness. These systems usually are sensor-based, and the alert time is the interval between the timing of the first detachment of debris flow by a sensor and its arrival into the threatened area. At the purpose of increasing the alert time, we propose an early warning system based on a model-cascade: nowcasting, hydrological- and triggering models. Nowcasting anticipates rainfall pattern that is transformed into runoff by the hydrological model. The triggering model estimates the volume of sediments that the runoff can entrain, and compares it with a critical threshold. If this is exceeded the alert is launched. The proposed early warning system is tested against the available data of the Rovina di Cancia (Northeast Italy) site

Pediatric Kidney Transplant. Effect of brain-dead donor resuscitation on delayed graft function

ABSTRACT Introduction and Aim of the Study. Studies devoted to brain dead donor parameters are all based on adult populations. The aim of this study was to analyze the correlation of delayed graft function (DGF) with brain-dead donor variables in a population of 116 consecutive pediatric recipients and to compare the clinical outcomes of non-DGF versus DGF recipients. Patients and Methods. We classified the recipients into two groups: group 0 (No. 11) with DGF and group 1 (No. 105) without DGF. Endpoints of the study were: DGF, 6 months graft function and short-term patient and graft survival. Multivariate analysis was performed to determine independent risk factors of DGF. Results. Monovariate analysis of donor parameters showed that donor age above 15 years, gender combination female donor/male recipients, and vascular cause of donor brain death were risk factors for prolonged DGF. The multivariate logistic regression model confirmed as independent risk factors for DGF donor age > 15 years and gender combination female donor to male recipient. After 6 months follow-up, the DGF group showed worse graft function, as well as a smaller incidence of normal histological pattern at graft biopsies. Conclusions. About parameters associated with brain-death donor resuscitation, except for non-traumatic cause of death, the others did not demonstrate any relationship with DGF. Importantly we show that donor age > 15 years and gender combination female donor to male recipient are clearly major independent risk factors for prolonged DGF in children. Furthermore in our paediatric series DGF revealed an important predictor of poor short-term graft function.RIASSUNTO Introduzione e scopo dello studio. In pazienti adulti, danni legati allo stato di morte cerebrale e alle manovre rianimatorie possono influenzare la ”delayed graft function” (DGF) e l‟outcome dell‟organo trapiantato. Scopo dello studio è stato valutare, in trapiantati di rene in età pediatrica, la correlazione tra parametri rianimatori del donatore cadavere e l‟outcome dell‟organo trapiantato. Materiali e Metodi. Il campione casistico è consistito in 116 pazienti (età ≤ 16 anni), sottoposti a trapianto di rene da cadavere dal 2004 al 2011. I pazienti sono stati divisi in gruppo 0 (No. 11) con DGF e gruppo 1 (No. 105) senza DGF. Gli “endpoints” dello studio sono stati: DGF, funzione dell‟organo trapiantato a 6 mesi dal trapianto e sopravvivenza del paziente e del rene trapiantato a 6 mesi. Risultati. L‟analisi monovariata dei parametri del donatore in morte cerebrale ha dimostrato che l‟età superiore a 15 anni, la combinazione donatore femmina/ricevente maschio e morte da accidente cerebrovascolare rappresentano fattori di rischio per lo sviluppo di DGF. Il modello di regressione logistica multivariata ha confermato come fattori di rischio indipendente per DGF l‟età del donatore e la combinazione donatore femmina/ricevente maschio. A 6 mesi di follow-up, il gruppo con DGF ha dimostrato una funzionalità renale e un quadro istologico bioptico significativamente peggiori rispetto al gruppo senza DGF. Conclusioni. Ad eccezione della causa di morte non traumatica, nessuna variabile ha influenzato la DGF nei bambini trapiantati. L'età del donatore (>15 anni) e la combinazione donatore femmina/ricevente maschio si sono rivelati importanti fattori di rischio indipendente per lo sviluppo di DGF. Inoltre, la DGF è risultato un fattore predittivo di funzionalità a breve termine dell‟organo trapiantato

Source modelling of the M5-6 Emilia-Romagna, Italy, earthquakes (May 20-29, 2012)

On 2012 May 20 and 29, two damaging earthquakes with magnitudes Mw 6.1 and 5.9, respectively, struck the Emilia-Romagna region in the sedimentary Po Plain, Northern Italy, causing 26 fatalities, significant damage to historical buildings and substantial impact to the economy of the region. The earthquake sequence included four more aftershocks with Mw ? 5.0, all at shallow depths (about 7–9 km), with similar WNW–ESE striking reverse mechanism. The timeline of the sequence suggests significant static stress interaction between the largest events. We perform here a detailed source inversion, first adopting a point source approximation and considering pure double couple and full moment tensor source models. We compare different extended source inversion approaches for the two largest events, and find that the rupture occurred in both cases along a subhorizontal plane, dipping towards SSW. Directivity is well detected for the May 20 main shock, indicating that the rupture propagated unilaterally towards SE. Based on the focal mechanism solution, we further estimate the co-seismic static stress change induced by the May 20 event. By using the rate-and-state model and a Poissonian earthquake occurrence, we infer that the second largest event of May 29 was induced with a probability in the range 0.2–0.4. This suggests that the segment of fault was already prone to rupture. Finally, we estimate peak ground accelerations for the two main events as occurred separately or simultaneously. For the scenario involving hypothetical rupture areas of both main events, we estimate Mw = 6.3 and an increase of ground acceleration by 50 per cent. The approach we propose may help to quantify rapidly which regions are invested by a significant increase of the hazard, bearing the potential for large aftershocks or even a second main shock.Published1658-16724T. Fisica dei terremoti e scenari cosismiciJCR Journalrestricte

Partial bowel obstruction in a 2-month-old child. A delayed diagnosis of anal abuse

We present the case of an anal sexual abuse involving a 2-month-old boy, who was admitted to the Pediatric Surgery Unit of the University of Padua for low bowel obstruction. The infant had been already hospitalized for 3 days in a peripheral hospital and treated with daily rectal wash-outs for a fecaloma. Only after a careful interpretation of the plain abdominal radiograph, along with the performance of a rectoscopy and a laparotomy, a vegetable foreign body (about 3 cm in diameter and 7 cm in length) was discovered in the sigma. The morphology and dimensions of the foreign body, as well as its location, left no doubt about the etiology of the partial bowel obstruction, proving that it was clearly related to an anal sexual abuse

Delayed graft function in pediatric deceased donor kidney transplantation: Donor-related risk factors and impact on two-yr graft function and survival: A single-center analysis

Abstract: There is mounting evidence that the quality of organs from cadaver donors may be influenced by events occurring around the time of brain death. Aim of this present study was to analyze the correlation of DGF with brain-dead donor variables in a singlecenter pediatric population and to evaluate DGF influence on patients- and grafts outcome. End-points of the study were DGF prevalence, DGF donor-related risk factors, graft function, patientand graft survival rate, respectively, at six, 12, and 24 months FU. The univariate analysis showed that donor age above 15 yr and vascular cause of donor brain death represented risk factors for DGF. The multivariate analysis confirmed as independent risk factors for DGF donor age >15 yr. At six months FU, DGF showed a negative impact on graft function. In conclusion, among all considered brain-dead donor resuscitation parameters, just nontraumatic cause of death turned out to be of impact for DGF. Donor age >15 yr represented the only independent risk factor for prolonged DGF in our series of children. At two-yr FU, DGF showed a transient negative impact on six-month graft function

Magmatic or Not Magmatic? The 2015–2016 Seismic Swarm at the Long-Dormant Jailolo Volcano, West Halmahera, Indonesia

Seismic swarms close to volcanoes often signal the onset of unrest. Establishing whether magma is the culprit and the unrest can be flagged as magmatic may be challenging. Here we analyze the spatio-temporal pattern of a seismic swarm that occurred in November 2015–February 2016 around Jailolo volcano, a long-dormant and poorly studied volcano located on Halmahera island, North Moluccas, Indonesia. The swarm included four Mw > 5 earthquakes and hundreds of events were felt by the population. We relocate the earthquakes using both the Indonesian Seismic Network and single-station location techniques. We find that the earthquakes cluster in a narrow strip, stretching 5 km E–W and 20 km N–S, migrating southward away from Jailolo volcano at ~10 km/d. We investigate the source mechanisms of the largest earthquakes via full moment tensor inversion. The non-double-couple component is around 50%, such that the earthquakes, besides normal faulting, included a relatively large opening component. After a thorough examination of the possible causes of the Jailolo swarm we conclude that a laterally propagating dike of tens of millions of cubic meters is the triggering mechanism for the seismicity. The swarm marks the first documented magmatic unrest at Jailolo. We find that there is a probability >0.1 that the unrest will last for more than 2 years. This magmatic unrest calls for the classification of Jailolo volcano as active, and for an urgent assessment of the associated volcanic hazard