首都圏・近畿圏における大都市圏地殻構造調査

Deep seismic profiling was performed in the Kanto and Kinki areas to obtain a better estimation of strong ground motions. In the Kanto area, we identify the seismogenic source fault on the upper surface of the Philippine Sea plate. The depth to the top of this plate, 4 to 26 km, is much shallower than previously estimated from the distribution of seismicity. This shallower plate geometry changes the location of the maximum finite slip of the 1923 Kanto earthquake, and its location corresponds to a zone of poor reflection on the mega-thrust, namely, a strong reflectivity zone along the mega-thrust coincidences with aseismic slip zone. In the Kinki area, 120-km-long seismic reflection profiling was carried out from Osaka to Suzuka across the Osaka and Ise basins and several active faults. Deep sub-horizontal reflectors are found at 26 and 16km in depth. The shallower re flectors correspond to the base of the seismogenic zone. Dipping reflectors, probably deeper extensions of active faults, merge into the mid-crustal reflectors

A mobile ELF4 delivers circadian temperature information from shoots to roots

Extended Data and Source Data can be found at https://doi.org/10.1038/s41477-020-0634-2Ajuts: the Mas laboratory is funded by the FEDER/Spanish Ministry of Economy and Competitiveness, the Ramon Areces Foundation and the Generalitat de Catalunya (AGAUR). The P.M. laboratory also acknowledges financial support from the CERCA Program, Generalitat de Catalunya and by the Spanish Ministry of Economy and Competitiveness through the Severo Ochoa Program for Centers of Excellence in R&D 2016-2019 (SEV-2015-0533).The circadian clock is synchronized by environmental cues, mostly by light and temperature. Explaining how the plant circadian clock responds to temperature oscillations is crucial to understanding plant responsiveness to the environment. Here, we found a prevalent temperature-dependent function of the Arabidopsis clock component EARLY FLOWERING 4 (ELF4) in the root clock. Although the clocks in roots are able to run in the absence of shoots, micrografting assays and mathematical analyses show that ELF4 moves from shoots to regulate rhythms in roots. ELF4 movement does not convey photoperiodic information, but trafficking is essential for controlling the period of the root clock in a temperature-dependent manner. Low temperatures favour ELF4 mobility, resulting in a slow-paced root clock, whereas high temperatures decrease movement, leading to a faster clock. Hence, the mobile ELF4 delivers temperature information and establishes a shoot-to-root dialogue that sets the pace of the clock in root

日本の本州中部山北地域の島弧―島弧衝突帯における深層掘削

We carried out borehole drilling in the Yamakita area near an active fault of the arc-arc collision zone in the western part of Kanagawa Prefecture. Slime and core samples were obtained. The borehole geology was established by examined them using petrographic analyses and geophysical logging data. We found that the southwestern slope of Mt. Maruyama was down-faulted from the northern slope of the mountain by an unknown fault. After drilling was completed, the borehole was established as a Hi-net seismic observation station. Data are collected by the Hi-net observation system and made available through the INTERNET

High-resolution seismic reflection profiling across the surface rupture associated with the 2004 Mid-Niigata Prefecture earthquake, central Japan : data acquisition and processing

The 200.4 Mid-Niigata Prefecture earthquake (Mj 6.8) generated surface ruptures along the eastern rim of the Uonuma hills. To reveal the relationship between a seismogenic source fault and surface ruptures, shallow, high-resolution seismic reflection profiling was undertaken across the surface ruptures and the active faults. The seismic source was a mini-vibrator and seismic data were recorded by a digital telemetry system. The source and receiver interval was 10 m4 The seismic data were processed using conventional CMP seismic reflection methods. The resultant depth-converted seismic section portrays an emergent thrust beneath the surface rupture associated with the Mid-Niigata Prefecture earthquake

High-resolution seismic reflection profiling across the Senya fault at Hanaoka, northern Honshu, Japan: Data acquisition and processing

The Senya fault, northern Honshu, Japan, which generated the Rikuu earthquake (Mj 7.2) 1896, is a typical intra-arc active thrust. Subsurface geometry provides essential information for better understanding strong ground motions and crustal deformation processes. A high-resolution seismic reflection survey was conducted along the 63km long seismic line across the toe of the thrust to reveal the subsurface geometry. The seismic source was a Mini-vibrator truck and the receiver interval was 10 m. The seismic data were processed by the standard common mid-point method. The Senya fault is clearly identified as a boundary between horizontal reflectors of the basin fill in the Yokote basin and moderately dipping reflectors beneath the Senya hills. The thrust occurred in late Miocene mudstone, and shows a flat and ramp geometry. The emergent thrust dips 30 degrees down to 500m, and changes its dip to subhorizontal following the distribution of the mudstone