TY - JOUR A1 - Perez-Lopez, Raul A1 - Martin-Velazquez, Saul A1 - Sanchez-Moral, Sergio A1 - Patyniak, Magda A1 - Lopez-Gutierrez, Jose A1 - Cuezva, Soledad A1 - Lario, J. A1 - Silva, P. G. A1 - Rodriguez-Pascua, M. A. A1 - Giner-Robles, J. L. T1 - New insights on speleoseismology: The geothermal gradient and heat flow values in caves for the study of active faults JF - Quaternary international : the journal of the International Union for Quaternary Research N2 - Normally in paleoseismology, the study of the tectonic slip-rate is performed in trenches on the fault scarp, or by the estimation of fault movements from the geomorphic features. In this work, we have carried out a paleoseismic analysis of the Benis Fault, located in southeast Spain, combined with a geothermal analysis inside a deep cave related to the fault (-350 m). Thus, we have estimated the last earthquake magnitude and time of occurrence from evidence of ceiling collapse and displaced carbonate blocks inside a cave, which is developed across the fault. The magnitude was obtained from the application of the empirical relationship of the fault parameters and coseismic vertical displacement, yielding a value ranging between M 5.9 and M 6.5. Moreover, we dated this paleoearthquake by the paleontological record of a "Lynx pardinus spelaea", with an age of 65 +/- 18 ka BP. Additionally, we have measured the thermal profile of the Benis Cave (-350 m of depth), from single rock point temperature measurements during 2 years. The temperature profile shows three different parts inside the cave, the shallow heterogeneous thermal zone till 50 m depth; the homogeneous thermal zone 150 m till with constant temperature and the hetero-thermal deep zone, deeper than 150 m and till the deepest zone (350 m). Furthermore, we have estimated the Vertical Geothermal Gradient, 1.85 degrees C/100 m for the deepest zone (-150; -290 m). The temperature increases with depth, showing a reverse thermal profile in comparison with normal gradients in deep caves. Finally, we have calculated the heat flux of 0.46 mWm(2). (C) 2016 Elsevier Ltd and INQUA. All rights reserved. KW - Speleoseismology KW - Active fault KW - Cave KW - Slip-rate KW - Heat flux Y1 - 2017 U6 - https://doi.org/10.1016/j.quaint.2016.11.026 SN - 1040-6182 SN - 1873-4553 VL - 451 SP - 165 EP - 175 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Mechie, James A1 - Abu-Ayyash, Khalil A1 - Ben-Avraham, Zvi A1 - El-Kelani, R. A1 - Mohsen, Amjad A1 - Rumpker, Georg A1 - Saul, J. A1 - Weber, Michael H. T1 - Crustal shear velocity structure across the Dead Sea Transform from two-dimensional modelling of DESERT project explosion seismic data N2 - An analysis of the shear (S) waves recorded during the wide-angle reflection/refraction (WRR) experiment as part of the DESERT project crossing the Dead Sea Transform (DST) reveals average crustal S-wave velocities of 3.3-3.5 km s(-1) beneath the WRR profile. Together with average crustal P-wave velocities of 5.8-6.1 km s(-1) from an already published study this provides average crustal Poisson's ratios of 0.26-0.27 (V-p/V-s = 1.76-1.78) below the profile. The top two layers consisting predominantly of sedimentary rocks have S- wave velocities of 1.8-2.7kms(-1) and Poisson's ratios of 0.25-0.31 (V-p/V-s = 1.73-1.91). Beneath these two layers the seismic basement has average S- wave velocities of around 3.6 km s(-1) east of the DST and about 3.7 km s(-1) west of the DST and Poisson's ratios of 0.24-0.25 (V-p/V-s = 1.71-1.73). The lower crust has an average S-wave velocity of about 3.75 km s(-1) and an average Poisson's ratio of around 0.27 (V-p/V-s = 1.78). No Sn phase refracted through the uppermost mantle was observed. The results provide for the first time information from controlled source data on the crustal S-wave velocity structure for the region west of the DST in Israel and Palestine and agree with earlier results for the region east of the DST in the Jordanian highlands. A shear wave splitting study using SKS waves has found evidence for crustal anisotropy beneath the WRR profile while a receiver function study has found evidence for a lower crustal, high S-wave velocity layer east of the DST below the profile. Although no evidence was found in the S-wave data for either feature, the S-wave data are not incompatible with crustal anisotropy being present as the WRR profile only lies 30 degrees off the proposed symmetry axis of the anisotropy where the difference in the two S-wave velocities is still very small. In the case of the lower crustal, high S-wave velocity layer, if the velocity change at the top of this layer comprises a small first-order discontinuity underlain by a 2 km thick transition zone, instead of just a large first-order discontinuity, then both the receiver function data and the WRR data presented here can be satisfied. Finally, the S-wave velocities and Poisson's ratios which have been derived in this study are typical of continental crust and do not require extensional processes to explain them Y1 - 2005 ER - TY - JOUR A1 - Tilmann, F. A1 - Zhang, Y. A1 - Moreno, M. A1 - Saul, J. A1 - Eckelmann, F. A1 - Palo, M. A1 - Deng, Z. A1 - Babeyko, Andrey A1 - Chen, K. A1 - Báez, Juan Carlos A1 - Schurr, B. A1 - Wang, R. A1 - Dahm, Torsten T1 - The 2015 Illapel earthquake, central Chile: A type case for a characteristic earthquake? JF - Geophysical research letters N2 - On 16 September 2015, the M-W = 8.2 Illapel megathrust earthquake ruptured the Central Chilean margin. Combining inversions of displacement measurements and seismic waveforms with high frequency (HF) teleseismic backprojection, we derive a comprehensive description of the rupture, which also predicts deep ocean tsunami wave heights. We further determine moment tensors and obtain accurate depth estimates for the aftershock sequence. The earthquake nucleated near the coast but then propagated to the north and updip, attaining a peak slip of 5-6 m. In contrast, HF seismic radiation is mostly emitted downdip of the region of intense slip and arrests earlier than the long period rupture, indicating smooth slip along the shallow plate interface in the final phase. A superficially similar earthquake in 1943 with a similar aftershock zone had a much shorter source time function, which matches the duration of HF seismic radiation in the recent event, indicating that the 1943 event lacked the shallow slip. Y1 - 2016 U6 - https://doi.org/10.1002/2015GL066963 SN - 0094-8276 SN - 1944-8007 VL - 43 SP - 574 EP - 583 PB - American Geophysical Union CY - Washington ER -