We developed a new method to classify the faulting types of small earthquakes using interevent waveform similarity and applied it to earthquakes in the northeast Japan subduction zone. In the method, ...we used separate time windows for P and S waves and established a relationship between waveform similarity and differences in focal mechanisms from event pairs whose focal mechanisms we know. Then we applied the relationship to many pairs of such focal‐mechanism‐known events (5607 from the moment tensor catalogue and 3623 events from the interplate repeating earthquakes catalogue) and focal‐mechanism‐unknown events for the period from 1984 to 2013. As a result, 8984 earthquakes were newly classified into interplate (N = 5401), noninterplate thrust (N = 631), normal (N = 1070), and strike‐slip faulting earthquakes (N = 165). From the new data set, which doubles the number of mechanism types, we confirmed that there have been almost no interplate earthquakes in the area of large coseismic slip of the Tohoku‐oki earthquake since that event. We also saw that this trend continued until at least the end of 2013, suggesting a nearly complete stress release and slow interplate stress recovery. The abundant interplate aftershocks also indicate the precise spatial extent of postsesimic slip, which is usually difficult to obtain from land‐based geodetic data. The postseismic slip also suggests stress concentration at the asperities of the 1968 Tokachi‐oki (M7.9) and 1994 Sanriku‐oki (M7.6) earthquakes. The present‐day faulting types offshore Tohoku correlated well with the static‐stress change from the Tohoku‐oki earthquake, suggesting a stress state change during the earthquake cycle of megathrust earthquakes.
Key Points
Faulting types of small earthquakes are classified based on waveform similarity
Interplate seismicity shows locked and slipping areas after the M9 earthquake
Faulting type distribution is consistent with the stress due to the main shock
Aim
Atomoxetine (ATX) is a non‐central stimulant and a standard treatment for adult attention‐deficit/hyperactivity disorder (ADHD). The long‐term efficacy of Atomoxetine is about 40% at 6 months. ...The variability in efficacy between individuals is thought to be related to patient‐specific factors, but no detailed research has been conducted. In this retrospective cohort study, we aimed to identify the factors associated with Atomoxetine efficacy.
Methods
A total of 147 patients with attention‐deficit/hyperactivity disorder aged ≥18 years who were using Atomoxetine for the first time were included in this study. The outcome was treatment success (treatment maintained for at least 6 months and improvement in symptoms). Symptom assessment was based on the overall improvement in symptoms judged by an expert physician.
Results
Of the patient sample, 103 (70.1%) achieved the outcome. Logistic regression analysis identified “the maximum dose of ATX” and “gambling habit” as factors associated with efficacy ( P < 0.05). In the process of Atomoxetine titration, the larger the maximum dose, the higher the efficacy was shown to be. Gambling habits may be indicative of impulsivity, which is among the core symptoms of attention‐deficit/hyperactivity disorder. Thus, a gambling habit may be considered a surrogate marker for impulsivity.
Conclusions
Knowledge of these factors will help healthcare professionals to predict the likely efficacy of Atomoxetine in a given patient before subscribing it, facilitating individualized pharmacotherapy for adult attention‐deficit/hyperactivity disorder.
We retrospectively examined factors associated with the efficacy of atomoxetine for adult ADHD. The maximum dose of atomoxetine and gambling habit were identified as significant factors related to the efficacy.
We examined the temporal variation of the size of repeating earthquakes related to the 2011 Tohoku‐oki earthquake (M9.0) in the northeastern Japan subduction zone for the period from July 1984 to the ...end of 2011. The repeaters (M2.5–6.1) show postseismic magnitude increases for most sequences located in the area of large postseismic slip at the downdip extension of the M9 source region. The magnitudes of the first events after the M9 earthquake increased by an average of about 0.3 for sequences having three or more earthquakes over the 9 months following it. We also examined the slip area in detail for Kamaishi repeaters whose magnitudes had been M4.9 ± 0.2 but which increased by about 1 after the M9 earthquake. Waveform modeling shows that the slip area for the post‐M9 Kamaishi earthquakes overlaps with that before the Tohoku‐oki earthquake but enlarged by about 6 times. Until the occurrence time of the last event (September 2011) in the analysis period, the rupture area remained larger than before but appeared to shrink over time. The enlargement of the rupture area suggests that an aseismic‐to‐seismic transition occurred in the region surrounding the pre‐M9 repeaters and is most likely related to fast loading of the repeaters due to rapid postseismic slip estimated to have occurred in the area. The existence of conditionally stable regions around the repeating earthquakes and/or patches slightly larger than the earthquake nucleation sizes may explain such behavior. The temporal change of loading rate is an important factor in determining earthquake size in this case.
Key Points
Postseismic responses of repeaters are examined for the Tohoku‐oki earthquake
A fast loading due to postseismic slip caused increased moment and slip areas
The phenomenon suggests aseismic‐to‐seismic transitions in the surrounding area
A dense nationwide seismic network recently constructed in Japan has been yielding large volumes of high-quality data that have made it possible to investigate the seismic structure in the Japanese ...subduction zone with unprecedented resolution. In this article, recent studies on the subduction of the Philippine Sea and Pacific plates beneath the Japanese Islands and the mechanism of earthquake and magma generation associated with plate subduction are reviewed. Seismic tomographic studies have shown that the Philippine Sea plate subducting beneath southwest Japan is continuous throughout the entire region, from Kanto to Kyushu, without disruption or splitting even beneath the Izu Peninsula as suggested in the past. The contact of the Philippine Sea plate with the Pacific plate subducting below has been found to cause anomalously deep interplate and intraslab earthquake activity in Kanto. Detailed waveform inversion studies have revealed that the asperity model is applicable to interplate earthquakes. Analyses of dense seismic and GPS network data have confirmed the existence of episodic slow slip accompanied in many instances by low-frequency tremors/earthquakes on the plate interface, which are inferred to play an important role in stress loading at asperities. High-resolution studies of the spatial variation of intraslab seismicity and the seismic velocity structure of the slab crust strongly support the dehydration embrittlement hypothesis for the generation of intraslab earthquakes. Seismic tomography studies have shown that water released by dehydration of the slab and secondary convection in the mantle wedge, mechanically induced by slab subduction, are responsible for magma generation in the Japanese islands. Water of slab origin is also inferred to be responsible for large anelastic local deformation of the arc crust leading to inland crustal earthquakes that return the arc crust to a state of spatially uniform deformation.
We estimate the configuration of the Philippine Sea plate (PHS) subducted beneath Kanto to understand the seismotectonics in the Tokyo metropolitan area. In addition to small repeating earthquakes ...that delineate both the upper and lower boundaries of the PHS, previously unrecognized converted waves at its upper boundary from lower‐boundary repeater sources provide a new constraint on the position of the boundary. The results from 794 S‐to‐P and 212 P‐to‐S converted waves together with ∼200 repeater locations show that (1) the PHS has a wedge‐like shape, decreasing in thickness from 50 km beneath Tokyo to zero at its northeastern limit, and (2) the PHS is relatively flat in the eastern part of Kanto and bends upward near its northeastern limit. From the fact that the PHS in the Izu‐Bonin forearc also has a similar wedge‐like shape, we infer that its shape was formed before its subduction. On the other hand, the relatively flat PHS at its northeastern limit and its upward bend are probably a consequence of ongoing deformation from an interaction with the underlying thick Pacific plate (PAC). The history of the PHS as a forearc before subduction and its contact with the PAC after subduction suggests that the temperature of this part of the PHS is colder than other regions, which probably causes anomalously deep seismicity on the PHS in Kanto. Colder PHS temperatures imply that the source regions of large earthquakes may extend deeper than expected, an important fact when assessing the locations of disastrous earthquakes for Tokyo.
The 2011 Tohoku megathrust earthquake ruptured a vast region of the northeast Japan Trench subduction zone in a way that had not been enough anticipated by earthquake and tsunami risk scenarios.
We ...analyzed the Tohoku rupture combining high-frequency back-projection analysis with low frequency kinematic inversion of the co-seismic slip. Results support the to-day well-accepted broadband characteristics of this earthquake. Most of the seismic moment is released during the first 100 s, with large co-seismic slip (up to 55 m) offshore Miyagi in a compact region on the landward side of the trench. Coherent high-frequency radiation areas and relatively low co-seismic slip are a distinctive signature of the slab–mantle interface. The broadband characteristics of the Tohoku rupture are interpreted, integrating the seismic activity and structure information on the NE Japan forearc region, as a signature of along-dip segmentation and segment interactions, that result from thermal structure, plate geometry, material composition and fracture heterogeneities along the plate boundary interface. Deep mantle corner flow and low dehydration rates along the cold subduction slab interface lead to an extended seismogenic slab–mantle interface, with strong bi-material contrast controlling larger propagation distance in the downdip preferred rupture direction. Off Miyagi, plate bending below the mantle wedge, ∼142.3°E at ∼25 km depth, is associated with the eastern limit of the deep M7–8-class thrust-earthquakes, and of the strongest coherent high-frequency generation areas. The region of the slab–crust interface between the mantle wedge limit, ∼142.7°E at ∼20 km depth, and a trenchward plate bending, ∼143.2°E at ∼15 km, acted as an effective barrier resisting for many centuries to stress-loading gradient induced by deep stable sliding and large earthquakes along the slab–mantle interface. The 2011 Tohoku earthquake, whose hypocenter is located on the east side of the mantle wedge limit, released the accumulated stress in this region and succeeded to overcome the plate bending, driving the upper plate boundary interface to slip co-seismically, regardless its frictional property, thanks to a combination of dynamic effects associated with bi-material rupture directivity and stress changes induced by reflection from the surface of waves released by the unstable slip. This conceptual framework provides elements for reappraisal of long-term seismic activity and occurrence of rare and extreme tsunamigenic megathrust in other subduction zones, like those of North-Central Lesser Antilles, Central and Northern Chile.
•Broadband megathrust characteristics and along-dip segment interactions.•Dynamically driven large shallow co-seismic slip and tsunami sources.•Seismic signature of subduction structure, slab dehydration and geometry.•Variable recurrence of great and megathrust earthquakes in subduction zones.•Stagnant mantle wedge and slab–mantle large thrust-earthquakes.
Objective: We aimed to clarify factors associated with the ability to seek help among older male caregivers who care for women with dementia in their families.Patients and Methods: This information ...will inform strategies to support their continued provision of long-term care. Participants were 364 male caregivers recruited from three places: The study period was 2017–2018. We obtained ethical approval for this study from the relevant ethics committee.Results: The ability to seek help for care problems among male caregivers was normally distributed. We found that more than 90% of older male caregivers did not actively seek help to resolve care problems, suggesting that older male caregivers had problems with long-term care. In the high score group, health status and the number of emotional support persons in the household were significantly and somewhat strongly positively correlated. The low score group showed a significant and rather weak positive correlation between economic status and health status, and the number of emotional supporters inside and outside the household.Positive correlations for the high score group were self-esteem and depressive symptoms, and self-esteem and resources. Positive correlations for the low score group were self-esteem and depressive symptoms, self-esteem and resources, and resources and depressive symptoms.Conclusion: Male caregivers are more likely to seek help if they are employed or play a role in their community. Nurses also need to support male caregivers with positive words and praise to help them use available support and resources and continue to provide long-term care. It is important for healthcare professionals to observe whether a caregiver presents with depressive symptoms or has long-term care problems because older male caregivers do not seek help. Collaboration between caregivers and medical, long-term care, and welfare professionals is necessary. Direct and timely intervention is needed.
Temporal seismic observations from pop-up type ocean-bottom seismometers were used to detect tectonic tremors immediately following the 2011 Tohoku-Oki earthquake in the northern periphery of the ...aftershock area. Near-field observations clearly distinguished tremors from regular earthquakes based on their spectral shape in the frequency band of 1–4 Hz. In addition to tremors accompanied by very low-frequency earthquakes (VLFEs), we detected 130 tremors without known VLFE activity during April–October 2011. The newly detected tremors were in the vicinity of a sequence of small repeating earthquakes, indicating a mixed distribution of tremors and regular interplate earthquakes in the region. Tremor activity was high immediately after the deployment of seismometers and gradually decreased. In addition, the tremor activity fluctuated with two activations with an interval of approximately 90 days, similar to the intervals between tremor bursts after 2016. The results of the study suggest that the observed tremors occurred under the influence of aseismic slip caused by the decaying afterslip of the preceding Tohoku-Oki and Mw 7.4 interplate earthquakes and episodic accelerations with a quasi-periodicity unique to the area.
Children with Kawasaki disease are prescribed acetylsalicylic acid powder as an antipyretic analgesic and antiplatelet agent; however, some of it remains in the mouth, leading to a bitter or sour ...taste. To address this issue, an in-hospital mini-tablet formulation of acetylsalicylic acid was developed. In order to use the mini-tablets safely and effectively, dissolution tests alone are not sufficient. Therefore, an open-label crossover study on six healthy participants was conducted to evaluate comparative pharmacokinetic parameters. The pharmacokinetic parameters of salicylic acid were Cmax: 4.80 ± 0.79 mg/L (powder; P), 5.03 ± 0.97 mg/L (mini-tablet; MT), AUC0–12: 18.0 ± 3.03 mg-h/L (P), 18.9 ± 4.59 mg-h/L (MT), those of acetylsalicylic acid Cmax: 0.50 ± 0.20 mg/L (P), 0.41 ± 0.24 mg/L (MT), AUC0–12: 0.71 ± 0.27 mg-h/L (P), 0.61 ± 0.36 mg-h/L (MT), with no significant differences between the mini-tablet and powder formulations. Although pharmacokinetic results obtained from adults cannot be directly applied to children, the results of this study are important for predicting pharmacokinetics. Furthermore, a formulation that can improve medication adherence in children who have difficulty taking acetylsalicylic acid powder, thus contributing to pediatric drug therapy.
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