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During moderate to deep (35–260 km) earthquakes within the Philippine-sea slab along the Ryukyu arc, distinctive later phases after S are observed across the Japanese archipelago for epicentral distances from 1500 to 2200 km, producing anomalous amplification of ground motion in central and northern Japan. Broad-band observations show that these later phases have a faster apparent wave speed (7–9.5 km s−1) than S , and are dominant at low frequencies (0.05–1 Hz), indicating S -wave reflections returned from the upper mantle with strong attenuation for high frequencies. Numerical simulation of seismic wave propagation in 3-D models including subduction of both the Pacific (PAC) and Philippine-sea (PHS) plates reveal the origin of these reflections. The triplicated S wave front from the 410 km discontinuity undergoes wide-angle reflection at the top of the Pacific slab bringing strong amplitudes in a narrow band of epicentral distance near 1500 km. Also, wide-angle S reflections at the 660 km discontinuity are reinforced by refraction when travelling through the high-wave speed Pacific slab; these arrive at the surface beyond 2000 km epicentral distance. The characteristics of the deep mantle reflections and the distribution of large ground motion across Japan due to the reflections are strongly dependent on the source depth and distance to the Ryukyu earthquakes. Tomographic imagery for western Japan indicates loss of the high-wave speed signal of the PAC slab below 200 km depth; the character of the large S reflections and pattern of enhanced ground motions favours a model in which the PAC slab is thinned rather than fully broken. The peculiar pattern of ground motion from Ryukyu earthquakes can be useful for constraining deep slab structures that are difficult to identify based on tomography. [ABSTRACT FROM AUTHOR]

Ypthima ring butterflies fly short distances over grasslands. In spite of their weak flying ability, Ypthima are widely distributed in the Old World tropics extending to temperate regions. Our study provides the first phylogenetic scenario for Ypthima butterflies based on mitochondrial COI, nuclear EF-1a and RpS5 genes. Bayesian inference trees were constructed and calibrated using an assumption of most recent common ancestor (MRCA) expansion due to vicariance at 1.55 Mya (= geologically obtained formative time of the Ryukyu Islands) following the protocol of BEAUti. The trees contain seven clades of the morphological motschuskyi + sordina group which form a polytomy with a single MRCA. These clades are Ypthima multistriata, divided into three main subspecies in Japan, Tsushima- Korea-China and Taiwan, Ypthima akragas on Taiwan highlands, Ypthima riukiuana on Okinawa and Ypthima masakii on Ishigaki- Iriomote, Ryukyu and Ypthima kitawakii + Ypthima phania in Yunnan. These endemic species are characterized by having three ocelli on the ventral surface of the hindwing. The Ypthima tree consists of two major clades (subgena Ypthima and Thymipa primarily with three or four to five ocelli), concordant to a morphologybased cladogram (Shirôzu & Shima, 1979; Shima, 1988). The latter five-ocellus subclade of philomela includes the seven-ocellus African genus Ypthimomorpha, hitherto suggested on morphological grounds to be weakly separated from Ypthima. [ABSTRACT FROM AUTHOR]