High probability of successive occurrence of Nankai megathrust earthquakes.

Great earthquakes along the Nankai megathrust in south-western Japan feature in the top priority list of Japan's disaster management agenda. In May 2019, an alert system was incepted to issue public warnings when the probability of an earthquake occurrence along the Nankai megathrust became higher than usual. One of the cases that trigger the issuance of public warnings is when a great earthquake occurred and another one of the same scale is anticipated within a short period of time. Although such "twin ruptures" have occurred multiple times along the Nankai megathrust, the quantification of the probability of such twin ruptures has never been attempted. Based on global statistics and local earthquake occurrence history, we estimated the probability of a successive occurrence of two M8 or larger earthquakes within 3 years globally and along the Nankai megathrust to be 5.0-18% and 4.3-96%, respectively. The timing of the second earthquake followed the Omori-Utsu law in global statistics, which allowed the estimation of the probability for the successive occurrence of Nankai megathrust earthquakes in arbitrary time frames. The predicted probability for the one-week timeframe was 100-3600-fold higher than that of the norm, endorsing the necessity for the warning scheme.

Serum and Adipose Dipeptidyl Peptidase 4 in Cardiovascular Surgery Patients: Influence of Dipeptidyl Peptidase 4 Inhibitors.

Dipeptidyl peptidase 4 (DPP-4) is a novel adipokine and may be involved in the association between adipose tissue and metabolic syndrome. We investigated DPP-4 and adiponectin levels in the serum, subcutaneous adipose tissue (SAT), and epicardial adipose tissue (EAT), and their relationship with preoperative factors, as well as comparing the DPP-4 levels in SAT and EAT with and without DPP-4 inhibitors. This study included 40 patients (25 men, age 67.5 ± 13.8 years). The serum adipokine, DPP-4, and adiponectin levels in SAT and EAT were measured using ELISA and Western blotting. The DPP-4 and adiponectin levels were significantly higher in the SAT than in the EAT. The serum DPP-4 and DPP-4 activity levels had no correlation with the DPP-4 levels in the SAT and EAT, but the DPP-4 levels in the SAT and EAT had a positive correlation. The DPP-4 levels in the SAT were positively correlated with atherosclerosis, diabetes mellitus, DPP-4-inhibitor use, and fasting blood glucose. The DPP-4 levels in the EAT showed a negative correlation with eGFR and a positive correlation with atrial fibrillation. The DPP-4 activity in the serum had a lower tendency in the group taking DPP-4 inhibitors than in the group not taking them. DPP-4 inhibitors may suppress angiogenesis and adipose-tissue hypertrophy.

Continuous permeability measurements record healing inside the Wenchuan earthquake fault zone.

Permeability controls fluid flow in fault zones and is a proxy for rock damage after an earthquake. We used the tidal response of water level in a deep borehole to track permeability for 18 months in the damage zone of the causative fault of the 2008 moment magnitude 7.9 Wenchuan earthquake. The unusually high measured hydraulic diffusivity of 2.4 × 10(-2) square meters per second implies a major role for water circulation in the fault zone. For most of the observation period, the permeability decreased rapidly as the fault healed. The trend was interrupted by abrupt permeability increases attributable to shaking from remote earthquakes. These direct measurements of the fault zone reveal a process of punctuated recovery as healing and damage interact in the aftermath of a major earthquake.