Resumen: A brittle deformation tectonic analysis was performed in central Spain (Spanish Central System and Madrid Basin) in order to decipher and understand the deformation processes that take place in a typical intracontinental zone. 1174 fault slickensides obtained in materials with ages between Late Cretaceous and Quaternary have been analyzed
by means of fault population analysis methods to reconstruct paleostress tensors. Nine earthquake focal mechanisms have been determined, with magnitudes ranging between 3 and 4.1. With regard to regional structural features and sedimentary record data, the characteristics of present-day and neotectonic stress fields have been figured out, which determine the neotectonic period for this region.
Thus, we have established that the intraplate zone represented by central Spain has been subjected to a stress field from the Middle Miocene until the present-day with a largest horizontal shortening direction (SHMAX) located between N130E and N160E.
Finally, three paleostress maps with the main active structures are presented for: (a) Middle Miocene to Late Miocene, the period when the Spanish Central System was mainly formed, (b) Late Miocene to Quaternary, and (c) the present-day stress field, deduced from earthquake focal mechanisms.
Palabras clave: Neotectonics; Seismotectonic; Fault; Focal mechanism; Active stresses; Stress evolution; Central Spain
Resumen: The present-day thermal state of the martian interior is a very important issue for understanding the 22
internal evolution of the planet. Here, in order to obtain an improved upper limit for the heat flow at 23
the north polar region, we use the lower limit of the effective elastic thickness of the lithosphere loaded 24
by the north polar cap, crustal heat-producing elements
(HPE) abundances based on martian geochem- 25
istry, and a temperature-dependent thermal conductivity for the upper mantle. We also perform similar 26
calculations for the south polar region, although uncertainties in lithospheric flexure make the results 27
less robust. Our results show that the present-day surface and sublithospheric heat flows cannot be 28
higher than 19 and 12 mWm2, respectively, in the north polar region, and similar values might be 29
representative of the south polar region (although with a somewhat higher surface heat flow due to 30
the radioactive contribution from a thicker crust). These values, if representative of martian averages, 31
does not necessarily imply sub-chondritic HPE bulk abundances for Mars (as previously suggested), since 32
(1) chondritic composition models produce a present-day total heat power equivalent to an average sur- 33
face heat flow of 14–22 mWm2 and (2) some convective models obtain similar heat flows for the pres- 34
ent time. Regions of low heat flow may even have existed during the last billions of years, in accordance 35
with several surface heat flow estimates of 20 mWm2 or less for terrains loaded during Hesperian or 36
Amazonian times. On the other hand, there are some evidences suggesting the current existence of 37
regions of enhanced heat flow, and therefore average heat flows could be higher than those obtained 38
for the north (and maybe the south) polar region.
Resumen: Value-at-Risk (VaR) is commonly used for financial risk measurement. It has recently become even more important, especially during the 2008-09 global financial crisis. We pro-pose some novel nonlinear threshold conditional autoregressive VaR (CAViaR) models that incorporate intra-day price ranges. Model estimation and inference are performed using the Bayesian approach via the link with the Skewed-Laplace distribution.
We examine how a range of risk models perform during the 2008-09 fnancial crisis, and evaluate how the crisis afects the performance of risk models via forecasting VaR. Empirical analysis is conducted
on five Asia-Pacific Economic Cooperation stock market indices as well as two exchange rate series. We examine violation rates, back-testing criteria, market risk charges and quantile loss function values to measure and assess the forecasting performance of a variety of risk models. The proposed threshold CAViaR model, incorporating range information, is shown to forecast VaR more eficiently than other models, across the series considered, which should
be useful for financial practitioners.
