http://hdl.handle.net/2122/242 Mon, 20 May 2013 22:46:38 GMT 2013-05-20T22:46:38Z http://hdl.handle.net/2122/8682 Title: Magnitude scale for LP events: a quantification scheme for volcanic quakes Authors: Del Pezzo, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Bianco, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Borgna, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Abstract: The peculiar source characteristics of long-period seismic events (time persistency of the source, low-frequency peaks in the source spectrum, absence of high-frequency radiation) prevent the formation of a definite high-frequency coda in the seismograms. In contrast, this is well formed in volcano–tectonic quakes. For this reason, the widely used duration magnitude scale that is based on the proportionality between the energy and the coda duration cannot be used for long-period estimation. In observatory practice, the long-period magnitude is sometimes estimated using the same duration magnitude scale, leading to confusing results. In this report, we show a new method to estimate the magnitude of long-period events that generally occur for volcanoes, with some application examples from data for Mt Etna (Italy), Colima Volcano (Mexico) and Campi Flegrei (Italy). Sun, 28 Apr 2013 22:00:00 GMT http://hdl.handle.net/2122/8682 2013-04-28T22:00:00Z http://hdl.handle.net/2122/8671 Title: Possible model of electromagnetic signals before earthquakes Authors: Dudkin, F.; Lviv Centre of Institute for Space Research, Ukraine; Korepanov, V.; Lviv Centre of Institute for Space Research, Ukraine; Hayakawa, M.; University of Electro-Communications, Japan; De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: Few days before many earthquakes a general change in the ratio of vertical to horizontal magnetic field components in the ULF band, often called “polarization”, has been observed that can be considered as a magnetic precursor of the subsequent earthquake. To explain such a specific behavior, we propose a simple model based on a linear current approximation depending on some assumption on the signal to noise ratio. This model is confirmed through a comparison that has been carried out between the experimental magnetic field data at Matsushiro (Japan, 1998.06.30, M=4.7) and Simeiz (Crimea, Ukraine, 1998.10.16, M=4.3 and 1998.10.18, M=4.3) earthquakes. About 1 – 2 days before these events we had recorded the anomalous decrease of the ratio of vertical to horizontal magnetic field components in Pc4 – Pc3 band. The NE-SW direction of the corresponding current linear model well agrees with the main tectonic feature of both seismogenic events. Additionally we also estimate the signal to noise ratio limits for the detection of ULF magnetic field components in Corralitos and Stanford campus for Loma Prieta (MS 7.1, 1989) earthquake. Mon, 31 Dec 2012 23:00:00 GMT http://hdl.handle.net/2122/8671 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8670 Title: A few earthquake conundrums resolved Authors: Crampin, S.; British Geological Survey, Edinburgh, Scotland, UK; Gao, Y.; Institute of Earthquake Science, China Earthquake Administration, Beijing, China; De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: Several fundamental questions (conundrums) about earthquakes and rocks are inexplicable in terms of conventional sub-critical geophysics. These questions have become so familiar that they are now generally accepted as the way earthquakes and rocks behave and are not recognised as presenting conceptual difficulties. These conundrums are resolved by a new understanding of fluid-rock deformation, where fluid-saturated microcracks in almost all rocks are so closely-spaced they verge on failure and hence are highly-compliant critical-systems which impose a range of new properties on conventional sub-critical geophysics. This new understanding of fluid-rock deformation, this New Geophysics, allows earthquakes to be stress-forecast, and has implications and applications to many solid Earth developments. Tue, 29 Jan 2013 23:00:00 GMT http://hdl.handle.net/2122/8670 2013-01-29T23:00:00Z http://hdl.handle.net/2122/8662 Title: The Volcano-Seismic Clock of the South American Pacific Margin - A Possible First Link Between Natural Disasters Prevention and Expanding Earth Authors: Scalera, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Editors: Scalera, Giancarlo; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Abstract: A volcano-seismic correlation was for a long time suspected to occur on the Pacific margin of South America. Scalera (2008) using the data available in 2006 in the Smithsonian Institution Catalogue of the volcanic eruptions, has revealed evidence that earthquakes happened into the South-American Wadati-Benio zone – with magnitude greater than 8.4 –are associated to an enhanced rate of volcanic eruptions, but has been impossible to determine the causal chain between the two phenomena. After 2006, the effort of the Smithsonian Institution to improve our knowledge of this region has resulted in a greatly increased completeness of the catalogue, adding the new eruptions for the 2000- 2010 interval, but also an additional 50% of new entries in the list of the Andean volcanoes. The occurrence of the Chilean earthquake of Maule – 27 February 2010 (M=8.8); occurred at five decades from the 1960 quake – has been the occasion to rework all the data searching for additional clues able to indicate a preferred causal direction eruptions-earthquakes or earthquakes-eruptions – or from a third more general cause (e.g. a mantle movements) to both eruptions and earthquakes. This short note discusses the three above-said hypotheses and tries to establish if these results could be useful to the aims of the Civil Protection in the programs of prevention and/or forecasting of natural disasters. Fri, 30 Nov 2012 23:00:00 GMT http://hdl.handle.net/2122/8662 2012-11-30T23:00:00Z http://hdl.handle.net/2122/8647 Title: Anomalous far-field geodetic signature related to the 2009 L’Aquila (central Italy) earthquake Authors: Atzori, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Chiarabba, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Devoti, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Lanari, R.; IREA-CNR; Bonano, M.; IREA-CNR Abstract: The broad availability of geodetic measurements for the Mw 6.3 April 6th 2009 L’Aquila earthquake allowed an unprecedented description of the co- and post-seismic ground deformations, leading to the definition of the Paganica fault geometry and kinematics. Through DInSAR, we found, in a wide area of 20 kilometres on the Paganica hangingwall, a further displacement up to 7 cm, which might have occurred in the earthquake proximity. In this study, we explore the possibility of the co-, post- and pre-seismic alternative scenarios. Although our data are not sufficient to undoubtedly prove that this signal occurred before the main event, this seems to be the most likely hypothesis based on tectonics constraints and image acquisition times. The nature of this deformation remains unclear, but we speculate that deep fluids played a role. These results can drive ad hoc requirements for future space-based missions and design of the GPS network. Mon, 31 Dec 2012 23:00:00 GMT http://hdl.handle.net/2122/8647 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8619 Title: Quasi-synchronous multi-parameter anomalies associated with the 2010–2011 New Zealand earthquake sequence Authors: Qin, K.; College of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing, China; Wu, L. X.; Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs/Ministry of Education of P.R. China (Beijing Normal University), Beijing, China; De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Meng, J.; College of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing, China; Ma, W. Y.; College of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing, China; Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: Positive thermal anomalies about one month before the 3 September 2010 Mw Combining double low line 7.1 New Zealand earthquake and " coincidental" quasi-synchronous fluctuations of GPS displacement were reported. Whether there were similar phenomena associated with the aftershocks? To answer it, the following was investigated: multiple parameters including surface and near-surface air temperature, surface latent heat flux, GPS displacement and soil moisture, using a long-term statistical analysis method. We found that local thermal and deformation anomalies appeared quasi-synchronously in three particular tectonic zones, not only about one month before the mainshock, but also tens of days before the 21 February 2011 Mw Combining double low line 6.3 aftershock, and that the time series of soil moisture on the epicenter pixel had obvious peaks on most of the anomalous days. Based on local tectonic geology, hydrology and meteorology, the particular lithosphere-coversphere-atmosphere coupling mode is interpreted and four mechanisms (magmatic-hydrothermal fluids upwelling, soil moisture increasing, underground pore gases leaking, and positive holes activating and recombining) are discussed. Sun, 15 Apr 2012 22:00:00 GMT http://hdl.handle.net/2122/8619 2012-04-15T22:00:00Z http://hdl.handle.net/2122/8618 Title: Source Parameters of the 2004 Kobarid (Western Slovenia) Seismic Sequence. Authors: Franceschina, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Gentili, S.; Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Centro Ricerche Sismologiche, Cussignacco, Udine, Italia. Editors: Slejko, D. Abstract: The Kobarid area (western Slovenia) was struck by two seismic sequences in 1998 and 2004. Corresponding mainshocks, occurred on April 12, 1998 and July 12, 2004, had magnitude MW =5.7 and MW =5.2, respectively and were located 2.6 km away from each other. Both of them were recorded by the Friuli-Venezia Giulia Seismometric Network, managed by the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), installed in north-eastern Italy (http://www.crs.inogs.it). During the sequences, the network recorded hundreds of aftershocks and both standard locations and duration magnitude (MD) estimations were performed. The seismic activity lasted 198 and 135 days, respectively and consisted of 700 events with MD in the range [1.5, 4.6] and 300 events with MD in the range [1.1, 3.6], respectively (Bressan et al., 2009). In this work, we estimate the seismic moment, M0, the corner frequency, fC, the Brune stress drop, ΔσB, the apparent stress, σa and the radiated energy, ES, of the mainshock and of 164 aftershocks of the Kobarid (2004) seismic sequence. The obtained results are compared with two previous analysis performed in the same region, concerning the source parameter scaling of the background seismicity (Franceschina et al., 2006) and of other seismic sequences (Bressan et al., 2007) occurred in the area. Mon, 19 Nov 2012 23:00:00 GMT http://hdl.handle.net/2122/8618 2012-11-19T23:00:00Z http://hdl.handle.net/2122/8617 Title: MECHANISMS AND RELATIONSHIP TO SOIL MOISTURE OF SURFACE LATENT HEAT FLUX ANOMALY BEFORE INLAND EARTHQUAKES Authors: Qin, K.; China University of Mining and Technology (Beijing), Beijing, 10083; Wu, L.; Beijing Normal University, Beijing, 100875; Liu, S.; Northeastern University, Shenyang, 110004; De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: The anomaly of SLHF, which is a key component of the Earth's energy balance and represents the heat flux from the Earth's surface to the atmosphere associated with evaporation or transpiration of water on the surface and subsequent condensation of water vapor in the troposphere, has been widely reported as a possible earthquake precursor. The causes are generally attributed to the increase in infrared thermal (IR) temperature and the air ionization produced by increased emanation of radon from the Earth's crust. In this paper, the theoretical analysis and case study show that there is close relationship between soil moisture and SLHF anomalies. For inland earthquakes, the increase of soil moisture due to the rising of groundwater level will bring with higher potential evaporation, leading to the increase of latent heat flux. Further study with more accurate soil moisture product after the new satellite mission will help us to better understand the influence of soil moisture on SLHF variation and their relations with seismogenic process. Sat, 21 Jul 2012 22:00:00 GMT http://hdl.handle.net/2122/8617 2012-07-21T22:00:00Z http://hdl.handle.net/2122/8616 Title: IMPORTANCE OF LITHOSPHERE-COVERSPHERE-ATMOSPHERE COUPLING TO EARTHQUAKE ANOMALY RECOGNITION Authors: Wu, L.; Beijing Normal University, Beijing, 100875, China; Qin, K.; China University of Mining and Technology (Beijing), Beijing, 10083, China; Liu, S.; Northeastern University, Shenyang, 110004, China; De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: The GEOSS under construction is providing space-,aero-,ground/sea-based multiple observations on planet Earth for the seismogenic process monitoring and earthquake precaution. The stress enhancement and energy accumulation in seismic activity area change locally the physical parameters of lithosphere with the developing of a series of effects that can comprise most of the following ones: initial cracks, the fracturing of rockmass, the changing of electromagnetic properties, the decreasing of dielectric constant, the re-activation of P-holes, the leaking of poregas, and the rise of water-level. The physical states of coversphere and atmosphere are to be affected due to the lithosphere-coversphere-atmosphere (LCA) coupling, and the signals from the underground, surface, and atmosphere to satellites are to be changed with parameter anomaly. We suggested that the LCA coupling is important for understanding GEOSS observations, especially for earthquake anomaly recognition (EAR). Using deviation-time-space-thermal (DTS-T) method for EAR, three recent major earthquakes (2009 Italy L'Aquila earthquake, 2010 China Yushu earthquake and 2010-2011 New Zealand earthquake sequence) are taken as typical cases for analysis to the multi-parameters anomalies, preceding the shocking, with quasi-synchronism and geoconsistency. The specific LCA coupling effects related with the earthquakes are also discussed in brief. Sat, 21 Jul 2012 22:00:00 GMT http://hdl.handle.net/2122/8616 2012-07-21T22:00:00Z http://hdl.handle.net/2122/8615 Title: Preliminary analysis of surface temperature anomalies that preceded the two major Emilia 2012 earthquakes (Italy) Authors: Qin, K.; China University of Mining and Technology, College of Geosciences and Surveying Engineering, Beijing, China; Wu, L. X.; China University of Mining and Technology, School of Environment Science and Spatial Informatics, Xuzhou, China; De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: In the 1980's, from an analysis of satellite images, Russian scientists reported on a short-term thermal infrared radiation enhancement that occurred before some medium-to-large earthquakes in central Asia [Gorny et al. 1988]. Since then, many researchers have been studying earthquake thermal anomalies with satellite remote sensing data [Qiang et al. 1991, Tronin 1996, Tramutoli et al. 2001, Ouzounov and Freund 2004, Saraf and Choudhury 2004, Aliano et al. 2008, Blackett et al. 2011]. Recently, abnormal surface latent heat flux [Dey and Singh 2003, Cervone et al. 2005, Qin et al. 2009, Qin et al. 2011, Qin et al. 2012], outgoing long-wave radiation [Ouzounov et al. 2007] and microwave radiation [Takashi and Tadashi 2010] have also been shown to precede earthquakes. To investigate the possible physical mechanisms of such satellite thermal anomalies, some studies conducted a series of detecting experiments on rock loaded to fracturing [Wu et al. 2000, Freund 2002, Wu et al. 2002, Wu et al. 2006a, Wu et al. 2006b, Freund et al. 2007], and some hypotheses have been proposed. These have included: leaking of pore-gas, and hence the resulting greenhouse effect [Qiang et al. 1995]; activating and recombining of p-holes during rock deformation [Freund 2002]; release of latent heat due to near-surface air ionization [Pulinets et al. 2006], and stress-induced thermal effects due to friction and fluids [Wu and Liu 2009]. According to the Istituto Nazionale di Geofisica e Vulcanologia (INGV; National Institute of Geophysics and Volcanology), two major earthquakes with almost the same large magnitudes struck northern Italy, on the Po Plain in the Emilia Region. The first hit on May 20, 2012, at 02:03 UTC, with ML 5.9 (44.89 °N, 11.23 °E; 6 km in depth), and the second on May 29, 2012, at 07:00 UTC, with ML 5.8 (44.85 °N, 11.09 °E; 10 km in depth). These caused a total of 27 deaths and widespread damage. In this study, the long-term temperature data from both satellite and ground (with greater emphasis on the satellite data) have been used to determine whether there were thermal anomalies associated with this Emilia 2012 seismic sequence. In particular, the next section will be dedicated to describing both the data and the method of analysis. In Section 3, we provide the more significant results, which we discuss in Section 4, together with the main conclusions. We acknowledge that this work cannot be exhaustive, as it will require more data and analyses. However, although further studies will be welcome, we are confident that we have done the best with the data at our disposal. Sat, 31 Dec 2011 23:00:00 GMT http://hdl.handle.net/2122/8615 2011-12-31T23:00:00Z