Low Coseismic Friction on the Tohoku-Oki Fault Determined from Temperature Measurements

The frictional resistance on a fault during slip controls earthquake dynamics. Friction dissipates heat during an earthquake; therefore the fault temperature after an earthquake provides insight into the level of friction. The JFAST project (IODP Expedition 343/343T) installed a borehole temperature observatory 16 months after the March 2011 M[subscript w]9.0 Tohoku-Oki earthquake across the fault where slip was ~50 m near the trench. After 9 months of operation, the complete sensor string was recovered. A 0.31°C temperature anomaly at the plate boundary fault corresponds to 27 MJ/m² of dissipated energy during the earthquake. The resulting apparent friction coefficient of 0.08 is considerably smaller than static values for most rocks.This is the author’s version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science, Volume 342 issue 6163 on 06 December 2013, DOI:10.1126/science.1243641

Low Coseismic Friction on the Tohoku-Oki Fault Determined from Temperature Measurements

The frictional resistance on a fault during slip controls earthquake dynamics. Friction dissipates heat during an earthquake; therefore, the fault temperature after an earthquake provides insight into the level of friction. The Japan Trench Fast Drilling Project (Integrated Ocean Drilling Program Expedition 343 and 343T) installed a borehole temperature observatory 16 months after the March 2011 moment magnitude 9.0 Tohoku-Oki earthquake across the fault where slip was ~50 meters near the trench. After 9 months of operation, the complete sensor string was recovered. A 0.31°C temperature anomaly at the plate boundary fault corresponds to 27 megajoules per square meter of dissipated energy during the earthquake. The resulting apparent friction coefficient of 0.08 is considerably smaller than static values for most rocks

The effect of different potassium fertilization of forecrop on the enzymatic activity of soil in spring barley cultivation

Celem badań było określenie zmian aktywności enzymatycznej gleby w czasie wegetacji jęczmienia jarego pod wpływem zróżnicowanego nawożenia przedplonu potasem. Doświadczenie polowe przeprowadzono w latach 2011 i 2013 w układzie całkowicie losowym w czterech powtórzeniach na poletkach doświadczalnych Uniwersytetu Przyrodniczo-Humanistycznego w Siedlcach. Przedplonem był groch siewny (Pisum sativum L.), pod który stosowano nawożenie: NK0, NK1, NK2, NK3, NK4, NK5 (N-20; K1-41,5; K2-83; K3-124; K4-166; K5-207,5 kg.ha–1). W uprawie jęczmienia jarego (Hordeum vulgare L.) uwzględniono nawożenie: N1,K0 N1K1, N1K1, N1K1, N1K1, N1K1 (N1-50, K1-41,5 kg·ha–1). Aktywność enzymów glebowych oznaczano czterokrotnie w czasie wegetacji, w próbkach pobranych z poziomu Ap (0-30 cm). Analizowana gleba charakteryzowała się bardzo wysoką aktywnością ureazy (średnio 365,5 mg N-NH4 h–1·kg–1 gleby). Największą aktywność dehydrogenaz oznaczono w glebie pobranej w czerwcu z obiektu nawozowego N1K1 (NK3 przedplon). Aktywność fosfatazy alkalicznej była dwukrotnie większa w porównaniu z aktywnością fosfatazy kwaśnej. Istotnie największą aktywnością fosfatazy alkalicznej (0,46-0,64 mmola PNP·h–1·kg–1 gleby) i kwaśnej (0,26-0,31 mmola PNP·h–1·kg–1 gleby) charakteryzowała się gleba pobrana z obiektu nawozowego N1K1 (jęczmień jary) NK1 (przedplon-groch siewny).The aim of the study was to determine changes of enzymatic activity of soil during spring barley vegetation. The field experiment was carried out in 2011 and 2013 with a completely randomised method, in four replicates, on the experimental plots of the Siedlce University of Natural Sciences and Humanities. The forecrop was pea (Pisum sativum L.), for which the following fertilisation was applied: NK0, NK1, NK2, NK3, NK4, NK5 (N-20; K1-41.5; K2-83; K3-124; K4-166; K5-207,5 kg ha–1). In spring barley (Hordeum vulgare L.) cultivation, six levels of fertilisation were applied: N1K0, N1K1, N1K1, N1K1, N1K1, N1K1 (N1-50, K1-41.5 kg ha–1). The activity of the enzymes was determined four times during vegetation, in soil samples taken from the Ap horizon (0-30 cm layer). The soil was characterised by very high urease act ivity (average 365.5 mg N-NH4 h–1 kg–1 dm of soil.) The highest activity of dehydrogenases was determined in the soil sampled in June from the N1K1 fertiliser treatment (NK3 forecrop). Alkaline phosphatase activity was twice as high as that of acid phosphatase. The highest activity of alkaline phosphatase (0.46-0.64 mmol PNP h–1 kg–1 dm of soil) and acidic (0.26-0.31 mmol PNP h–1 kg–1dm of soil) was characterized by soil taken from the fertiliser treatment N1K1 (spring barley) NK1 (forecrop-pea)