The spatiotemporal distributions of hypocenters and temporal change in seismicity patterns were investigated in details for events in the Yamagata‐Fukushima border earthquake swarm, which was a ...remotely triggered earthquake sequence by the 2011 Tohoku‐Oki earthquake. We relocated the hypocenters by applying the double‐difference location method to differential arrival time data obtained by waveform cross correlations together with the Japan Meteorological Agency catalogue data. The hypocenter distribution obtained clearly shows that the hypocenters are concentrated on several discrete planes and migrate along those planes from deeper to shallower levels instead of diffusing isotropically. Most of the events have nodal planes of focal mechanisms parallel to those discrete planes, suggesting that ruptures of individual events occurred along those macroscopic planes. The timing of earthquake occurrences is almost random during the initial ~50 days, but it gradually becomes temporally clustered in later periods, with the number of events decaying aftershock‐like after relatively large events. These observations suggest that the present swarm is caused by a reduction in frictional strength due to the increased pore pressure of fluids rising from greater depths in response to the decrease in arc‐normal compressional stress associated with the Tohoku‐Oki earthquake. The fluids permeated into several existing planes, reduced frictional strengths, caused the present earthquake swarm, and migrated upward along the planes with the hypocenters. Our previous observations that stress drops are systematically low and b‐values are high during the initial ~50 days can be readily explained if the pore pressure is especially high during that period.
Key Points
Relocated hypocenters are concentrated on several discrete planes and migrate along those planes from deeper to shallower levels
Earthquakes occur randomly in the initial ~50 days but are temporally clustered in later periods
These observations suggest that the swarm is caused by the increased pore pressure of rising fluids
We describe two transient slow slip events that occurred before the 2011 Tohoku-Oki earthquake. The first transient crustal deformation, which occurred over a period of a week in November 2008, was ...recorded simultaneously using ocean-bottom pressure gauges and an on-shore volumetric strainmeter; this deformation has been interpreted as being an M6.8 episodic slow slip event. The second had a duration exceeding 1month and was observed in February 2011, just before the 2011 Tohoku-Oki earthquake; the moment magnitude of this event reached 7.0. The two events preceded interplate earthquakes of magnitudes M6.1 (December 2008) and M7.3 (March 9, 2011), respectively; the latter is the largest foreshock of the 2011 Tohoku-Oki earthquake. Our findings indicate that these slow slip events induced increases in shear stress, which in turn triggered the interplate earthquakes. The slow slip event source area on the fault is also located within the downdip portion of the huge-coseismic-slip area of the 2011 earthquake. This demonstrates episodic slow slip and seismic behavior occurring on the same portions of the megathrust fault, suggesting that the faults undergo slip in slow slip events can also rupture seismically.
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► Transient crustal deformations were seen in 2008 and 2011 near the Japan Trench. ► The observed deformations are explained by M6.8 and M7.0 slow slip events. ► The slow slip events preceded moderate or large interplate earthquakes. ► The fault is located in the coseismic slip area of the 2011 Tohoku-Oki earthquake.
Crisis Communication, Liberal Democracy, and Ecological Sustainability provides a detailed and empirical analysis of the institutions, governing logics, risk-management practices, and crisis ...communication strategies involved in the 2007–2008 financial crisis, the 2010 BP oil crisis, and the 2011 Fukushima Daiichi nuclear crisis. These human-engineered crises threaten sustainability through resource depletion, environmental degradation, and the growth of geo-political conflicts. Yet, the corporations responsible have returned to profitability by externalizing risks to communities and governments. In response to this pattern of crisis management, Nadesan argues that contemporary financial and energy complexes pose significant threats to liberal democracy and ecological sustainability. This book will be of interest to scholars of communication studies, cultural studies, sociology, political science, anthropology, and economics.
Abstract
Exploiting the exogenous and regional nature of the Great East Japan Earthquake of 2011, this article provides a quantification of the role of input-output linkages as a mechanism for the ...propagation and amplification of shocks. We document that the disruption caused by the disaster propagated upstream and downstream along supply chains, affecting the direct and indirect suppliers and customers of disaster-stricken firms. Using a general equilibrium model of production networks, we then obtain an estimate for the overall macroeconomic impact of the disaster by taking these propagation effects into account. We find that the earthquake and its aftermaths resulted in a 0.47 percentage point decline in Japan’s real GDP growth in the year following the disaster.
The U.S. Congress asked the National Academy of Sciences to conduct a technical study on lessons learned from the Fukushima Daiichi nuclear accident for improving safety and security of commercial ...nuclear power plants in the United States. This study was carried out in two phases: Phase 1, issued in 2014, focused on the causes of the Fukushima Daiichi accident and safety-related lessons learned for improving nuclear plant systems, operations, and regulations exclusive of spent fuel storage. This Phase 2 report focuses on three issues: (1) lessons learned from the accident for nuclear plant security, (2) lessons learned for spent fuel storage, and (3) reevaluation of conclusions from previous Academies studies on spent fuel storage.
The repetition of slip during rupture process of earthquake is a debate issue which had never been confirmed clearly in the past big events due to the lack of dense near‐field observations and ...limited resolution in time of source model. The 2011 M9.0 Tohoku‐Oki earthquake generated a wealth seismic records which provided us an unprecedented opportunity to study the rupture evolution of giant earthquake at a high spatio‐temporal resolution. Here we use teleseismic, local strong motion and near‐field coseismic geodetic data to investigate the source rupture process of this event based on the parallel inversion technique. The results reveal a broad slip zone with remarkable large scale repeating slip during the earthquake. The inverted source model shows several time periods of energy release with three main peaks. These energy bursts and temporal rupture snapshots suggest repetition of a large scale slip on the biggest asperity. This rupture behavior resulted in >50 m slips on the slip zone and prolonged the entire rupture process for a long duration of ∼160 seconds. The proposed source model is in a good agreement with the aftershock distribution and can interpret the characteristics of local strong motions. Further investigations of repeating slip during this event are crucial which will deeply transform earthquake science from dynamic point of view.
Key Points
Large scale repeating slip was found during the 2011 Tohoku‐Oki earthquake
Repeating slip suggests by high resolution joint source inversion analysis
The repetition of slip resulted in >50 m slips and complex rupture process
In this work, we simulate the 2011 M9 Tohoku-Oki tsunami using new coseismic tsunami sources based on inverting onshore and offshore geodetic data, using 3D Finite Element Models (FEM). Such FEMs ...simulate elastic dislocations along the plate boundary interface separating the stiff subducting Pacific Plate from the relatively weak forearc and volcanic arc of the overriding Eurasian plate. Due in part to the simulated weak forearc materials, such sources produce significant shallow slip (several tens of meters) along the updip portion of the rupture near the trench. To assess the accuracy of the new approach, we compare observations and numerical simulations of the tsunami's far- and near-field coastal impact for: (i) one of the standard seismic inversion sources (UCSB; S
hao
et al.
2011
); and (ii) the new FEM sources. Specifically, results of numerical simulations for both sources, performed using the fully nonlinear and dispersive Boussinesq wave model FUNWAVE-TVD, are compared to DART buoy, GPS tide gauge, and inundation/runup measurements. We use a series of nested model grids with varying resolution (down to 250 m nearshore) and size, and assess effects on model results of the latter and of model physics (such as when including dispersion or not). We also assess the effects of triggering the tsunami sources in the propagation model: (i) either at once as a hot start, or with the spatiotemporal sequence derived from seismic inversion; and (ii) as a specified surface elevation or as a more realistic time and space-varying bottom boundary condition (in the latter case, we compute the initial tsunami generation up to 300 s using the non-hydrostatic model NHWAVE). Although additional refinements are expected in the near future, results based on the current FEM sources better explain long wave near-field observations at DART and GPS buoys near Japan, and measured tsunami inundation, while they simulate observations at distant DART buoys as well or better than the UCSB source. None of the sources, however, are able to explain the largest runup and inundation measured between 39.5° and 40.25°N, which could be due to insufficient model resolution in this region (Sanriku/Ria) of complex bathymetry/topography, and/or to additional tsunami generation mechanisms not represented in the coseismic sources (e.g., splay faults, submarine mass failure). This will be the object of future work.
The Syrian displacement crisis raises fundamental questions about the relationship between action to resolve conflicts and humanitarian aid to assist the victims and demonstrates the limits of ...humanitarian response, even on a massive scale, to resolve political crises. The increasingly protracted nature of the crisis also raises the need for the international community to think beyond just relief assistance and adopt developmental policies to help refugees become productive members of their host communities. The Consequences of Chaos looks beyond the ever-increasing numbers of Syria's uprooted population to consider the long-term economic, political, and social implications of this massive movement of people.
Since 9/11, why have we won smashing battlefield victories only to botch nearly everything that comes next? In the opening phases of war in Afghanistan, Iraq, and Libya, we mopped the floor with our ...enemies. But in short order, things went horribly wrong.
We soon discovered we had no coherent plan to manage the "day after." The ensuing debacles had truly staggering consequences-many thousands of lives lost, trillions of dollars squandered, and the apparent discrediting of our foreign policy establishment. This helped set the stage for an extraordinary historical moment in which America's role in the world, along with our commitment to democracy at home and abroad, have become subject to growing doubt. With the benefit of hindsight, can we discern what went wrong? Why have we had such great difficulty planning for the aftermath of war?
In The Day After, Brendan Gallagher-an Army lieutenant colonel with multiple combat tours to Iraq and Afghanistan, and a Princeton Ph.D.-seeks to tackle this vital question. Gallagher argues there is a tension between our desire to create a new democracy and our competing desire to pull out as soon as possible. Our leaders often strive to accomplish both to keep everyone happy. But by avoiding the tough underlying decisions, it fosters an incoherent strategy. This makes chaos more likely.
The Day After draws on new interviews with dozens of civilian and military officials, ranging from US cabinet secretaries to four-star generals. It also sheds light on how, in Kosovo, we lowered our postwar aims to quietly achieve a surprising partial success. Striking at the heart of what went wrong in our recent wars, and what we should do about it, Gallagher asks whether we will learn from our mistakes, or provoke even more disasters? Human lives, money, elections, and America's place in the world may hinge on the answer.
This paper studies information frictions between parents and children and their effect on human capital investments. I provide biweekly information to a random sample of parents about their child’s ...missed assignments. Parents have upwardly biased beliefs about their child’s effort. Providing information attenuates this bias and improves student achievement. Using data from the experiment, I estimate a persuasion game between parents and their children that shows that the treatment effect is due to more accurate beliefs and reduced monitoring costs. Policy simulations from the model demonstrate that improving school reporting or providing more information to parents can increase learning at low cost.
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