The Canterbury earthquake sequence provides an exceptional opportunity to investigate the effects of varying degrees of liquefaction on the built environment. Many multistory buildings in the Central ...Business District were heavily damaged by liquefaction-induced ground movements during the Christchurch earthquake, but not by other earthquakes (e.g., the Darfield and June 2011 events). Cone penetration test (CPT)-based liquefaction triggering evaluations were conservative. The conservatism in the liquefaction triggering assessments led to post-liquefaction ground settlement estimates that were generally similar for the large events in the earthquake sequence, whereas significant ground settlements and building damage in the CBD were only observed for the Christchurch earthquake. Moreover, the liquefaction-induced ground settlement procedures do not capture important shear-induced deformation mechanisms and the effects of ground loss due to sediment ejecta. Performance-based earthquake engineering requires improved procedures to capture the differing levels of performance observed in Christchurch.
•We examine the financial contagion between stock markets.•We identify the possible channels of transmission of the 2011 stock market crash.•We use the DAG-copula based approach to study the ...structure of causal dependence.•Diversification benefits are limited especially during crisis periods.
The objective of this paper is to empirically investigate whether there is a contagion phenomenon between the stock markets during the July–August-2011 stock market crash. When there is a market contagion, we will identify the propagation channel through which the crash is transmitted. Hence, after checking if there is financial contagion between the stock markets, we will see if the transmission mechanism “constraints of wealth” outweighs that of the “portfolio rebalancing”. An additional test covering the interdependence between the stock and bond markets during the crash helps us verify whether the transmission is due either to the “cross-market rebalancing” channel or to the “flight to quality” phenomenon.
On the basis of the combination of the copula theory and the directed acyclic graph to study the structure of causal dependence between the stock market during the period that lies between 01/02/2010 and 28/11/2012, we show that the links between countries are different between the pre-crash period and that of the crash. More specifically, the links that do not exist during normal times seem to have a major role during the crash period. We interpret this result as an evidence of the existence of pure contagion. On the one hand, the tests show that the channel of the “portfolio rebalancing” was the major mechanism for the spread of the crash. On the other hand, the phenomenon of the cross-market rebalancing existed only in Germany; whereas, that of the flight to quality was in all the other studied stock markets.
The 2011 North Nagano earthquake of M=6.7 occurred at the boundary of Nagano and Niigata prefectures in the next day following to the 2011 earthquake off the Pacific coast of Tōhoku. In the previous ...paper, literature survey on damage related to snow for this earthquake was performed referring the local Nagano prefectural newspaper articles. Continuing to this, the same survey was done with the documents of Niigata side. The snow effects to this earthquake are listed in time series from the beginning of disasters to their recovering processes. Lessons learned from this event are also discussed.
SUMMARY
For more than a decade, GRACE data have provided global mass redistribution measurements due to water cycles, climate change and giant earthquake events. Large earthquakes can yield gravity ...changes over thousands of kilometres from the epicentre for years to decades, and those solid Earth deformation signals can introduce significant biases in the estimate of regional-scale water and ice mass changes around the epicentres. We suggest a modelling scheme to understand their contribution to the estimates of water and ice mass changes and to remove the earthquake-related solid mass signals from GRACE data. This approach is composed of physics-based earthquake modelling, GRACE data correction and high-resolution surface mass change recovery. In this study, we examined the case of the 2011 Tohoku–Oki earthquake to better estimate the regional sea level and hydrological mass changes in the East Asia. The co- and post-seismic changes from GRACE observations were used to constrain the earthquake model parameters to obtain optimal self-consistent models for the earthquake source and the asthenosphere rheology. The result demonstrated that our earthquake correction model significantly reduced the mass change signals by solid Earth deformation from the time-series of regional surface mass changes on both land and oceans. For example, the apparent climate-related ocean mass increase over the East Sea was 1.59 ± 0.11 mm yr−1 for 2003–2016, significantly lower than the global mean ocean mass trend (2.04 ± 0.10 mm yr−1) due to contamination of the earthquake signals. After accounting for the solid mass changes by the earthquake, the estimate was revised to 1.87 ± 0.11 mm yr−1, that is increased by 20 per cent and insignificantly different from the global estimate.
SUMMARY
The orientations of faults activated relative to the local principal stress directions can provide insights into the role of pore pressure changes in induced earthquake sequences. Here, we ...examine the 2011 M 5.7 Prague earthquake sequence that was induced by nearby wastewater disposal. We estimate the local principal compressive stress direction near the rupture as inferred from shear wave splitting measurements at spatial resolutions as small as 750 m. We find that the dominant azimuth observed is parallel to previous estimates of the regional compressive stress with some secondary azimuths oriented subparallel to the strike of the major fault structures. From an extended catalogue, we map ten distinct fault segments activated during the sequence that exhibit a wide array of orientations. We assess whether the five near-vertical fault planes are optimally oriented to fail in the determined stress field. We find that only two of the fault planes, including the M 5.7 main shock fault, are optimally oriented. Both the M 4.8 foreshock and M 4.8 aftershock occur on fault planes that deviate 20–29° from the optimal orientation for slip. Our results confirm that induced event sequences can occur on faults not optimally oriented for failure in the local stress field. The results suggest elevated pore fluid pressures likely induced failure along several of the faults activated in the 2011 Prague sequence.
SUMMARY
We have developed an inversion method for estimating 3-D tectonic stress fields from centroid moment tensor (CMT) data of seismic events. To obtain reliable inversion analysis results, we ...need to use as much data as possible, ranging over different periods. In this study, we improved the previously developed CMT data inversion method to incorporate preceding inversion analysis results into the present analysis as direct prior information about the stress field. The spatial distribution of seismic events and/or their focal mechanisms in a region would change from one period to another, reflecting temporal stress changes there. In the improved inversion method, in addition to the hyperparameter controlling the roughness of stress fields, we introduced another hyperparameter that controls the relative weight of direct prior information to the observed data to be analysed. The relative weights of direct and indirect prior information to the observed data are appropriately determined by using Akaike's Bayesian Information Criterion. We applied the improved inversion method to the observed CMT data of seismic events of 24 yr (1997−2020) in northeast Japan, where the Tohoku-oki megathrust event (Mw 9.0) occurred on 11 March 2011 at the North American–Pacific Plate boundary. To investigate temporal changes in tectonic stress orientation, we divided the target period into the inter-, pre- and post-seismic periods of the megathrust event: P1 (January 1997−January 2007), P2 (February 2007−February 2011), and P3 (March 2011−December 2020). According to successive inversion analysis results for P1 and P2, we confirmed that the tectonic stress orientation was stable for 14 yr before the megathrust event. On the other hand, successive inversion analysis results for P2 and P3 indicated a possibility that the 2011 megathrust event caused significant changes in tectonic stress orientation in three regions. However, two of them were negative in the quantitative evaluation of the reliability of detected temporal changes. In conclusion, the stress orientation change in the region off Fukushima and Ibaraki, the southern margin of the main rupture area of the megathrust event, seems to be real.
Policy uncertainty reduces individual welfare when individuals have limited opportunities to mitigate or insure against the resulting consumption fluctuations. We field an original survey to measure ...the degree of perceived policy uncertainty in Social Security benefits and to estimate the impact of this uncertainty on individual welfare. Our central estimates show that on average individuals are willing to forgo 6 percent of the benefits they are supposed to get under current law to remove the policy uncertainty associated with their future Social Security benefits. This translates to a risk premium from policy uncertainty equal to 10 percent of expected benefits.
The paper analyzes the performance of a hospital system using a holistic and multidisciplinary approach. Data on impacts to the hospital system were collected using a standardized survey tool. A ...fault-tree analysis method is adopted to assess the functionality of critical hospital services based on three main contributing factors: staff, structure, and stuff. Damage to utility networks and to nonstructural components was found to have the most significant effect on hospital functionality. The functional curve is integrated over time to estimate the resilience of the regional acute-care hospital with and without the redistribution of its major services. The ability of the hospital network to offer redundancies in services after the earthquake increased the resilience of the Christchurch Hospital by 12%. The resilience method can be used to assess future performance of hospitals, and to quantify the effectiveness of seismic retrofits, hospital safety legislation, and new seismic preparedness strategies.
Permeability, an important crustal property that controls transport processes in Earth's shallow crust, is known to change during large earthquakes, with significant implications on the groundwater ...resources and contaminant transport. Analysis of the response of groundwater in wells to Earth tides has been increasingly used to detect such changes, but often multiple interpretations of the response changes are possible, making it difficult to ascertain its hydrological implications. Here we use data from a groundwater well in North China to illustrate the use of barometric response as a method to resolve this uncertainty. The tidal response of water level in this well shows abrupt coseismic increases of both phase shift and amplitude ratio after the far-field great 2011 Mw 9.1 Tohoku earthquake, which may be interpreted either as a large increase in the horizontal permeability of a confined aquifer or as an occurrence in the vertical permeability of an unconfined aquifer. Using data for the water-level response to barometric pressure we show that the aquifer was confined both before and after the Tohoku earthquake; thus the coseismic changes of the tidal response in this well are more likely to be due to an increase in the horizontal permeability. Interpretation of the tidal response shows a hereto unidentified change of poroelastic property in the far field of an earthquake, which stayed constant for ∼4 years after the earthquake until silt-cleaning in the well interrupted data collection. Thus the dynamic shaking during the Tohoku earthquake may have caused permanent deformation in the shallow crust at epicentral distances >1500 km.
•The 2011 Mw 9.1 Tohoku earthquake caused lasting hydrologic response in the far field.•Barometric response is used as an extra check of the post-seismic aquifer confinement.•Post-seismic hydraulic & poroelastic property changed for >4 yr in a far-field aquifer.•The earthquake may have caused permanent crustal deformation at distances >1500 km.
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