OSU Multimodal Machine Translation System Report

This paper describes Oregon State University's submissions to the shared WMT'17 task "multimodal translation task I". In this task, all the sentence pairs are image captions in different languages. The key difference between this task and conventional machine translation is that we have corresponding images as additional information for each sentence pair. In this paper, we introduce a simple but effective system which takes an image shared between different languages, feeding it into the both encoding and decoding side. We report our system's performance for English-French and English-German with Flickr30K (in-domain) and MSCOCO (out-of-domain) datasets. Our system achieves the best performance in TER for English-German for MSCOCO dataset.Comment: 5, WMT 201

P-wave image of the crust and uppermost mantle in southern California

We have determined a P-wave tomographic image of the crust and uppermost mantle in southern California by using 131,372 P-wave arrival times from 6,437 local earthquakes recorded by the Caltech-USGS Southern California Seismic Network in the past twelve years. The obtained image has a spatial resolution of 25 km in the horizontal direction and 8–11 km in depth. The tomographic image is found to correlate well with major surface geological features. In the shallow crust, sedimentary basins such as the Los Angeles Basin, Ventura Basin and Santa Maria Basin are well imaged as low velocities, while batholiths such as the Peninsular Ranges and San Gabriel Mountains are imaged as high velocities. In the deeper crust, the velocity is low beneath the Mojave Desert, Coso volcanic area and Salton Trough, while it is high beneath the Great Valley, Continental Borderland and the major basins. A high-velocity layer exists in the mid-crust beneath the Salton Trough, in good agreement with a previous study using seismic explosions and gravity data. In the uppermost mantle, the velocity is low beneath southeastern Sierra Nevada and the volcanic areas while it is high beneath the Mojave Desert and along the Pacific coast

The 1994 Northridge Earthquake: 3-D crustal structure in the rupture zone and its relation to the aftershock locations and mechanisms

A detailed 3-D P-wave velocity structure of the crust in the epicentral area of the 17 January, 1994 Northridge earthquake is determined by using 104,709 arrival times from 1673 Northridge aftershocks and 2948 other local earthquakes. A test performed using the data from the nearby portable stations suggests that the aftershock hypocenters relocated with the obtained 3-D model are accurate to about 2 km. We found that regions with high aftershock activity are generally associated with faster P-wave velocities. The velocity is high around the main south-dipping fault of the 1994 Northridge earthquake and the north-dipping fault of the 1971 San Fernando earthquake. A linear distribution of strike-slip aftershocks was found along a NE-SW boundary between high-velocity and low-velocity structures. To the west of this boundary a cluster of large shallow aftershocks with mixed mechanisms occurred in or near the border of a low-velocity area, while to the east aftershocks with thrust mechanisms occurred in a high-velocity area. These observations suggest that lateral variations of crustal properties are closely related to the fault segmentation in the Transverse Ranges. A better understanding of these features is important for long-term seismic hazard assessment in the Los Angeles area

The 1992 Landers earthquake sequence: Earthquake occurrence and structural heterogeneities

The June 28, 1992, Mw 7.3 Landers earthquake occurred in the southeastern Mojave Desert, California. Over 10,000 aftershocks of the earthquake were recorded by the Caltech-USGS Southern California Seismic Network (SCSN) in 1992. To investigate the relationship between complexities in the crustal structure and variations in seismicity, we have used a tomographic method to invert 145,098 P wave arrival times from 3740 Landers earthquake aftershocks and 1148 other events recorded by 60 permanent and temporary SCSN stations. We determined a detailed P wave tomographic image with a spatial resolution of about 5 km and relocated the hypocenters with the obtained 3-D velocity model. The results show a correlation between seismicity patterns and velocity patterns and a tendency for regions rich in seismicity to be associated with higher velocities. The higher velocity areas are considered to be strong and brittle parts of the fault zone, which are apt to generate earthquakes. In contrast, low velocity areas are probably more ductile and weaker, allowing aseismic slippage

Deep structure of Japan subduction zone as derived from local, regional, and teleseismic events

We have determined a detailed three-dimensional P wave velocity structure of the Japan subduction zone to 500-km depth by inverting local, regional, and teleseismic data simultaneously. We used 45,318 P wave arrivals from 1241 shallow and deep earthquakes which occurred in and around the Japan Islands. The arrival times are recorded by the Japan University Seismic Network which covers the entire Japan Islands densely and uniformly. We also used 4211 travel time residuals from 100 teleseismic events which are read from seismograms recorded by seismic stations in northeastern Japan. In comparison with the previous results obtained from only local and regional events, the present result for the area around the lower plate boundary and the mantle below the plate is determined more reliably because of the addition of 7035 data from 100 teleseismic events and 41 very deep earthquakes. In the crust and uppermost mantle, low-velocity zones are clearly visible beneath active volcanoes. In the mantle wedge the low-velocity zones generally parallel with the slab and exist continuously to a depth of about 200-km, which is consistent with the petrological, geochemical and geodynamic studies. We consider that the existence of volcanism-related low-velocity anomalies in the mantle wedge is a general Seismological characteristic of subduction zones, in light of all the available tomographic results for many subduction zones in the world. The Pacific slab beneath Japan is imaged more clearly than in previous studies as a high-velocity zone with a thickness of 80–90 km and a P wave velocity 4–6% higher than the normal mantle. Lower velocity anomalies are found in the mantle below the slab

P-wave tomography beneath Greenland

The Tenth Symposium on Polar Science/Ordinary sessions: [OG] Polar Geosciences, Wed. 4 Dec. / 3F Seminar room, National Institute of Polar Researc

Structural heterogeneity in the megathrust zone and mechanism of the 2011 Tohoku-oki earthquake (Mw 9.0)

The great 2011 Tohoku-oki earthquake (Mw 9.0) and its 339 foreshocks and 5,609 aftershocks (9–27 March 2011) were relocated using a three-dimensional seismic velocity model and local P and S wave arrival times. The distribution of relocated hypocenters was compared with a tomographic image of the Northeast Japan forearc. The comparison indicates that the rupture nucleation of the largest events in the Tohoku-oki sequence, including the mainshock, was controlled by structural heterogeneities in the megathrust zone

State of stress before and after the 1994 Northridge Earthquake

The state of tectonic stress in the epicentral area of the 17 January 1994, Northridge earthquake (Mw 6.7) is investigated by applying a stress inversion method to P-wave polarity data from earthquakes in Northridge from July 1981 to January 1994 and from the Northridge aftershocks during January 1994 to December 1995. A 3-D crustal model is used to trace the rays taking off from the hypocenter, which reduced the effects of large structural heterogeneities on the determination of the stress tensor. We found significant temporal changes of stress orientations induced by the Northridge earthquake. The principal pressure (P) axis is oriented N32°E from 1981 to June 1992, and N30°E from 28 June 1992 to 16 January 1994, suggesting that the stress field in Northridge was not affected by the 1992 Landers earthquake. During two weeks following the Northridge mainshock, the P-axis is oriented N13°E, which is a significant (17°) change from that before the earthquake (N30°E). Between February 1994 and August 1995 the P-axis orientation changes from N18°E to N26°E, and finally ends up at N34° by the end of 1995, which is close to that before the Northridge earthquake. These results suggest that the stresses rotated coseismically, then rotated more slowly back to their original orientation. The aftershocks caused by the mainshock changed the stress distribution in the crust, which showed up as a regional stress change. The stress recovery appears to have completed within two years after the mainshock, which is very short compared to the time scale of the earthquake cycle

Structure and dynamics of the E. coli chemotaxis core signaling complex by cryo-electron tomography and molecular simulations

To enable the processing of chemical gradients, chemotactic bacteria possess large arrays of transmembrane chemoreceptors, the histidine kinase CheA, and the adaptor protein CheW, organized as coupled core-signaling units (CSU). Despite decades of study, important questions surrounding the molecular mechanisms of sensory signal transduction remain unresolved, owing especially to the lack of a high-resolution CSU structure. Here, we use cryo-electron tomography and sub-tomogram averaging to determine a structure of the Escherichia coli CSU at sub-nanometer resolution. Based on our experimental data, we use molecular simulations to construct an atomistic model of the CSU, enabling a detailed characterization of CheA conformational dynamics in its native structural context. We identify multiple, distinct conformations of the critical P4 domain as well as asymmetries in the localization of the P3 bundle, offering several novel insights into the CheA signaling mechanism