High-quality lowest-frequency normal mode strain observations at the Black Forest Observatory (SW-Germany) and comparison with horizontal broad-band seismometer data and synthetics

International audienceWe present spectra concentrating on the lowest-frequency normal modes of the Earth obtained from records of the invar-wire strainmeters and STS-1 broad-band seismometers located in the Black Forest Observatory, Germany after the disastrous earthquakes off the NW coast of Sumatra in 2004 and off the coast near Tohoku, Japan in 2011. We compare the spectra to ones obtained from synthetic seismograms computed using a mode summation technique for an anelastic, elliptical, rotating, spherically symmetric Earth model. The synthetics include strain– strain-coupling effects by using coupling coefficients obtained from comparisons between Earth tide signals recorded by the strainmeters and synthetic tidal records. We show that for the low-frequency toroidal and spheroidal modes up to 1 mHz, the strainmeters produce better signal-to-noise ratios than the broad-band horizontal seismometers. Overall, the comparison with the synthetics is satisfactory but not as good as for vertical accelerations. In particular, we demonstrate the high quality of the strainmeter data by showing the Coriolis splitting of toroidal modes for the first time in individual records, the first clear observation of the singlet 2 S 0 1 and the detection of the fundamental radial mode 0 S 0 with good signal-to-noise ratio and with a strain amplitude of 10 −11. We also identify the latter mode in a record of the Isabella strainmeter after the great Chilean quake in 1960, the detection of which was missed by the original studies

High-quality lowest-frequency normal mode strain observations at the Black Forest Observatory (SW-Germany) and comparison with horizontal broad-band seismometer data and synthetics

We present spectra concentrating on the lowest-frequency normal modes of the Earth obtained from records of the invar-wire strainmeters and STS-1 broad-band seismometers located in the Black Forest Observatory, Germany after the disastrous earthquakes off the NW coast of Sumatra in 2004 and off the coast near Tohoku, Japan in 2011. We compare the spectra to ones obtained from synthetic seismograms computed using a mode summation technique for an anelastic, elliptical, rotating, spherically symmetric Earth model. The synthetics include strain–strain-coupling effects by using coupling coefficients obtained from comparisons between Earth tide signals recorded by the strainmeters and synthetic tidal records. We show that for the low-frequency toroidal and spheroidal modes up to 1 mHz, the strainmeters produce better signal-to-noise ratios than the broad-band horizontal seismometers. Overall, the comparison with the synthetics is satisfactory but not as good as for vertical accelerations. In particular, we demonstrate the high quality of the strainmeter data by showing the Coriolis splitting of toroidal modes for the first time in individual records, the first clear observation of the singlet 2S0/1 and the detection of the fundamental radial mode 0S0 with good signal-to-noise ratio and with a strain amplitude of 10^−11. We also identify the latter mode in a record of the Isabella strainmeter after the great Chilean quake in 1960, the detection of which was missed by the original studies

The ISC Bulletin as a comprehensive source of earthquake source mechanisms

In this article we summarize the availability of earthquake source mechanisms in the Bulletin of the International Seismological Centre (ISC). The bulletin in its current status contains ∼81 000 seismic events with only one associated mechanism solution and ∼25 000 events with at least two associated source mechanisms. The main sources of earthquake mechanisms in the ISC Bulletin are reported solutions provided by data contributors and ISC-computed focal mechanisms based on first motion polarities. Given the importance of using pre-determined fault plane solutions in different types of studies, here we briefly discuss the methodologies adopted by major data providers to the ISC and investigate the intra-event variability of the source mechanisms. We conclude that the overall agreement among different earthquake mechanisms for the same event as reported by different sources can show a similarity coefficient as high as 80&thinsp;%, based on the rotation angles of their best-fitting double couple solutions, for the majority of the cases. The earthquake source mechanisms discussed in this work are freely available within the ISC Bulletin websearch at http://doi.org/10.31905/D808B830.</p

Effect of initial infusion with calcium ions on some selected properties of dried apples

Podczas procesów technologicznych ilość składników odżywczych w surowcach ulega zmniejszeniu, co zmusza technologów do opracowywania metody uzupełniania tych strat. Wzbogacanie żywności w substancje odżywcze dotyczy zarówno substancji naturalnie w niej występujących oraz składników naturalnie w niej nieobecnych. Nasycanie jest jedną z metod wzbogacania żywności w składniki odżywcze. Celem pracy było zbadanie możliwości modyfikacji właściwości teksturalnych suszu jabłka, poprzez wstępne nasycanie tkanki jonami wapnia. Nasycanie prowadzono pod atmosferycznym oraz obniżonym ciśnieniem, przy użyciu 1, 3 i 5 % roztworu mleczanu wapnia. Następnie materiał suszono konwekcyjnie do stałej masy w temperaturze 70 °C. Właściwości teksturalne określono na podstawie testu łamania próbek suszu jabłka oraz testu ściskania rehydrowanego materiału. Przeprowadzono również ocenę sensoryczną suszy, podczas której oceniano barwę, zapach, smak, twardość i ogólne wrażenia sensoryczne odbierane przy ocenie próbki, obejmujące wszystkie oceniane wyróżniki. Test łamania dowiódł, że nasycanie oraz zwiększenie zawartości wapnia w próbkach nie wpłynęło w istotny sposób na właściwości mechaniczne suszu. Na podstawie testu ściskania stwierdzono, że materiał nasycany pod zmniejszonym ciśnieniem, charakteryzujący się większą zawartością wapnia, wykazał większe wartości pracy ściskania. Obecność jonów wapnia w tkance spowodowała uzyskanie niższych ocen za zapach i smak i mimo wyższych ocen za barwę i twardość, susze nasycane pod obniżonym ciśnieniem uzyskały niższe oceny ogólne. Ocena sensoryczna nie potwierdziła pomiarów instrumentalnych tekstury, które nie wychwyciły istotnych zmian następujących w mierzonych parametrach.During technological processes, the quantity of nutrients in raw materials decreases, thus, technologists are forced to develop a method to adjust those losses. Enriching food with nutrients refers both to the substances naturally occurring in it and to the components naturally absent in it. Infusion is one of the methods of enriching food with nutrients. The objective of the study was to research into the possibility of modifying textural properties of dried apple fruits using initial tissue infusion with calcium ions. The infusion process was carried out at an atmospheric and a decreased pressure, using a 1, 3, and 5 % solution of calcium lactate. Then, the material was convectively dried to get a constant mass at a temperature of 70ºC. Textural properties were determined based on a braking test of dried apples and a squeezing test of rehydrated material. The dried apples were sensory analyzed; the analysis comprised the assessment of colour, smell, taste, hardness, and general sensory impressions received whilst assessing all the above indicated parameters of the samples. The braking test proved that the infusion and the increased content of calcium in the samples did not significantly impact the mechanical properties of the dried material. Based on the squeezing test, it was found that the material infused at a decreased pressure with a higher content of calcium showed a higher value of squeezing work. The presence of calcium ions in the tissue caused the smell and taste to be lower rated, and, although the colour and hardness were higher rated, the general rating of the dried materials infused at a reduced pressure was lower. The sensory evaluation did not confirm the texture measurements taken using measuring instruments, which did not detect significant changes occurring in the parameters measured

Effect of blanching conditions of celeriac tissue on the texture properties of dried material

Celem pracy było określenie wpływu nasycania jonami wapnia oraz warunków blanszowania tkanki selera na kinetykę suszenia oraz właściwości teksturalne suszu. Blanszowanie prowadzono w wodzie destylowanej o temp. 60 i 95 °C w zróżnicowanym czasie oraz w roztworze mleczanu wapnia. Określono odkształcenie niszczące suszu w teście łamania i pracę cięcia uwodnionego suszu selera. Analizując wyniki otrzymane na podstawie krzywych suszenia selera stwierdzono, że im dłuższy był czas blanszowania w wodzie destylowanej, tym osiągano krótszy czas suszenia. Blanszowanie w roztworze mleczanu wapnia nie spowodowało zmian w czasie suszenia, w porównaniu z procesem prowadzonym w wodzie w tych samych warunkach. Jednocześnie badania wskazują, że działanie wysokiej temperatury podczas tradycyjnego blanszowania powoduje istotne zmiany we właściwościach mechanicznych suszonej tkanki selera, obserwowane głównie po jej uwodnieniu, a polegające na osłabieniu tekstury. Nasycanie jonami wapnia w czasie blanszowania spowodowało znaczny wzrost zawartości wapnia w tkance. Z uwagi na nieznaczne zmiany właściwości teksturalnych suszu otrzymanego z takiej tkanki można uznać, że nasycanie jonami wapnia tkanki selera podczas jej blanszowania może być jednym ze sposobów wzbogacania tkanki w analizowany pierwiastek.The objective of this paper was to study the effect of saturation using calcium ions, as well as the effect of conditions of blanching celeriac tissues on the kinetics of drying process and the texture properties of dried material. The blanching process was performed in distilled water at 60 °C and 95 °C, during varying time periods, as well as in the calcium lactate solution. The following was determined: destructive deformation destructing dried vegetable with the use of a breaking test; the cutting work of the hydrated celeriac. The analysis of the results obtained based on the celeriac drying curves allowed for the statement that the longer the duration time of blanching in distilled water was, the shorter the duration time of drying celeriac was. When blanching in the calcium lactate solution, no changes in the duration time of drying were found compared to the process performed in distilled water under the same conditions. On the other hand, the investigation results prove that high temperature if applied to traditional blanching process causes significant changes to occur in the mechanical properties of the celeriac tissue being dried, found mainly after the celeriac tissue is hydrated, i.e. weakening of the tissue texture. The saturation using calcium ions during blanching caused a significant increase in the Ca content in the tissue. Owing to insignificant changes in the textural properties of dried material produced from this tissue, the conclusion is that the saturation of the celeriac tissue using Ca ions during blanching can be one of the methods of enriching the tissue by adding the element analyzed

Assessment of SCARDEC source parameters of global large (Mw ≥ 7.5) subduction earthquakes

International audienceRapid and accurate source characterizations of large, shallow subduction earthquakes are key for improved tsunami warning efforts. We assess the quality of source parameters of large magnitude (Mw ≥ 7.5) shallow subduction earthquakes of the past 20 yr determined using SCARDEC, a recent fully automated broad-band body-wave source inversion technique for the fast estimation of the moment magnitude, depth, focal mechanism and source time functions of global events. We find that SCARDEC source parameters agree well with those reported in the global centroid moment tensor (GCMT) catalogue, with only the fault dip angle showing a tendency for steeper SCARDEC dip values than GCMT. We investigate this discrepancy through independent validation tests of the source models by: (i) testing how well they explain data not used in their construction, notably low-frequency normal mode data; and, (ii) assessing the data fit using 3-D forward modelling tools more sophisticated than those used to build the source models; specifically, we use a spectral element method for a 3-D earth model. We find that SCARDEC source parameters explain normal mode data reasonably well compared to GCMT solutions. In addition, for the 3-D earth model used in our experiments, SCARDEC dip angles explain body-wave data similarly or slightly better than GCMT. Moreover, SCARDEC dip angles agree well with results from individual earthquake studies in the literature and with geophysical constraints for different subduction zones. Our results show that SCARDEC is a reliable technique for rapid determinations of source parameters of large (Mw ≥ 7.5) subduction earthquakes. Since the SCARDEC method provides realistic source time functions allowing the fast identification of long-duration tsunami earthquakes, it is complementary to existing methods routinely used for earthquake monitoring and suitable for ocean-wide tsunami warning purpose

Assessment of SCARDEC source parameters of global large (Mw ≥ 7.5) subduction earthquakes

International audienceRapid and accurate source characterizations of large, shallow subduction earthquakes are key for improved tsunami warning efforts. We assess the quality of source parameters of large magnitude (Mw ≥ 7.5) shallow subduction earthquakes of the past 20 yr determined using SCARDEC, a recent fully automated broad-band body-wave source inversion technique for the fast estimation of the moment magnitude, depth, focal mechanism and source time functions of global events. We find that SCARDEC source parameters agree well with those reported in the global centroid moment tensor (GCMT) catalogue, with only the fault dip angle showing a tendency for steeper SCARDEC dip values than GCMT. We investigate this discrepancy through independent validation tests of the source models by: (i) testing how well they explain data not used in their construction, notably low-frequency normal mode data; and, (ii) assessing the data fit using 3-D forward modelling tools more sophisticated than those used to build the source models; specifically, we use a spectral element method for a 3-D earth model. We find that SCARDEC source parameters explain normal mode data reasonably well compared to GCMT solutions. In addition, for the 3-D earth model used in our experiments, SCARDEC dip angles explain body-wave data similarly or slightly better than GCMT. Moreover, SCARDEC dip angles agree well with results from individual earthquake studies in the literature and with geophysical constraints for different subduction zones. Our results show that SCARDEC is a reliable technique for rapid determinations of source parameters of large (Mw ≥ 7.5) subduction earthquakes. Since the SCARDEC method provides realistic source time functions allowing the fast identification of long-duration tsunami earthquakes, it is complementary to existing methods routinely used for earthquake monitoring and suitable for ocean-wide tsunami warning purpose

Effect of blanching parameters and methods of drying on mechanical properties of dried mushrooms

Celem pracy było zbadanie wpływu parametrów blanszowania oraz metod suszenia na właściwości mechaniczne suszonych pieczarek. Materiałem badawczym były pieczarki odmiany Agarcius bisporus, krojone w plastry grubości 5 mm, które poddawano blanszowaniu w wodzie przez 15, 30, 45 i 60 minut w temperaturze 60oC oraz przez 3 minuty w 95oC. Następnie materiał suszono trzema metodami: sublimacyjną (zamrażanie w –18 i –40oC), konwekcyjną oraz mikrofalowo-konwekcyjną. Właściwości mechaniczne określono przeprowadzając test zginania suszy sublimacyjnych i konwekcyjnych i test cięcia suszu mikrofalowego. Zdjęcia mikroskopowe wykazały znaczne zniszczenie struktury wewnętrznej pod wpływem wstępnej obróbki termicznej. Susze sublimacyjne, zamrażane w –40oC charakteryzowały się największymi wartościami pracy łamania podczas testu zginania. Jednocześnie, w wyniku zamrażania w wyższej temperaturze otrzymywano liofilizaty mniej odporne na odkształcenia. Najwyższymi siłami cięcia charakteryzowały się susze mikrofalowo-konwekcyjne wstępnie blanszowane w temperaturze 60oC przez krótszy czas. Analizując różne metody suszenia, nie stwierdzono jednoznacznego wpływu parametrów wstępnego blanszowania na właściwości mechaniczne pieczarek. Był on zależny od zastosowanego sposobu usuwania wody.The aim of this study was to investigate the influence of blanching parameters on mechanical properties of dried mushrooms. Mushrooms cv. Agarcius bisporus were cut into slices of thickness of 5 mm and blanched in water for 15, 30, 45 and 60 minutes at 60oC and for 3 minutes at 95oC. Then the material was dried using three methods: freeze-drying (freezing at –18 and –40oC), convective drying and microwave-convective drying. Mechanical proprieties were deter-mined using the breaking test for freeze-dried and convective dried material and the cutting test for microwave-convective dried mushrooms. Microscope photos showed considerable destruction of internal structure under the influence of thermal pretreatment. Freeze-dried material frozen at –40oC was characterised by the greatest cutting work during the bending test. Simultaneously, less resistant to deformation freeze-dried materials were obtained as result of freezing at higher temperature. The microwave-convective dried material initially blanched at 60oC for shorter time was characterised by the highest cutting force. No unique influence of blanching parameters on mushrooms mechani-cal properties was found during the analysis of different drying methods. This was dependent on the way of water removing

Source models of great earthquakes from ultra low-frequency normal mode data

International audienceWe present a new earthquake source inversion technique based on normal mode data for the simultaneous determination of the rupture duration, length and moment tensor of large earthquakes with unilateral rupture. We use ultra low-frequency (f w⩾8.5): (i) Sumatra-Andaman (26th December 2004); (ii) Nias, Sumatra (28th March 2005); (iii) Bengkulu (12th September 2007); (iv) Tohoku, Japan (11th March 2011); (v) Maule, Chile (27th February 2010); and, (vi) the 24 May 2013 Mw 8.3 Okhotsk Sea, Russia, deep (607 km) event. While finite source inversions for rupture length, duration, magnitude and fault mechanism are possible for the Sumatra-Andaman and Tohoku events, for all the other events their lower magnitudes only allow stable point source inversions of mode multiplets. We obtain the first normal mode finite source model for the 2011 Tohoku earthquake, which yields a fault length of 461 km, a rupture duration of 151 s, and hence an average rupture velocity of 3.05 km/s, giving an independent confirmation of the compact nature of this event. For all the other earthquakes studied, our new source models agree well with previous studies. We do not find any unexplained systematic differences between our results and those in the literature, suggesting that for the wave frequencies considered, the moment magnitude and the fault mechanism of the earthquakes studied do not show a strong frequency dependence