The Doppler weather radar on board the research vessel Mirai, which was installed in 1998, was replaced by a dual-polarization Doppler weather radar in 2014. This study explores the beam blockage for both radars on board the Mirai. Reflectivity data from long-term observations were used to calculate the probability of detection (POD) at a given range, azimuth, and elevation relative to the Mirai. Azimuthal sectors suffering from beam blockage caused by the infrastructure of the Mirai were characterized by pronounced minima of the POD in their centers and significant discontinuities of the POD on their edges. An objective method was developed to ascertain the boundaries of the blocked sectors based on the rate of change of the POD gradient along the azimuthal direction. According to the distinct signatures of the POD, detailed beam blockage information for both radars was identified in different ship-relative elevations. Although beam blockage for both radars occurred from low to high elevations, the total azimuths of the low-level blocked sectors for the dual-polarization Doppler radar decreased by more than half. This improvement was attributed to the higher location of the antenna for the dual-polarization Doppler radar. This accurate beam blockage information will facilitate the quality control of the Mirai radar data.

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近年，海洋研究開発機構は多くの地震探査航海を日本海で実施し，その探査中マルチビームによる高品質な海底地形データを同時に取得している．海底地形はその海域におけるテクトニクスや構造発達史を解明する手かがりの1つであり，地震研究においても，例えば震源断層のパラメータの検討の観点から重要である．したがって，高品質な海底地形データを活用することができれば，断層の長さに関する検討の精度が上がり，震源断層の大きさの議論の進展にもつながる．その結果，日本海における地震活動・活構造と地殻構造の関係をより統合的に研究を推進することができる．本報告では，地震探査時に取得された海底地形データを加えた日本海全域及びその周辺の地形データを用いて，それらを統合したDEM（数値標高モデル:Digital Elevation Model）データを作り，さらにそのデータを用いて方向依存性のない立体感が得られる赤色立体地図を作製した結果について記す．

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Seismic tomograms are the images of Earth's internal characteristics that help us understand geophysical phenomena. As a website at http://csmap.jamstec.go.jp, CSMAP provides an easy way to select and view Earth's seismic tomograms through a working web browser, acting as a graphical user interface to the underlying tomogram engine. The tomogram engine computes Earth's cross section tomograms with a depth range from Earth's surface to Core-Mantle Boundary (CMB) based on the seismic velocity perturbation model selected by the user from the three predefined models available in the website. Given a tomographic model and a cross section profile specified by two geocoordinates, CSMAP tells the engine to generate a tomogram. It sends the result back to the user in an HTML page, or as a PDF or Postscript file when the engine finishes computation.Written mostly in Java, CSMAP is run by Apache Tomcat on a Linux server. It works with all major web browsers including Google Chrome, Firefox, and Microsoft Internet Explorer. The user interface was designed to be simple and intuitive, yet it provides necessary help texts in tooltips and introduction pages in more details. With its small footprint on the server, CSMAP is easy to install and maintain. Since its launch on a JAMSTEC's public server in June 2015, the site has been running constantly and reliably without any major problems.In this report, we introduce CSMAP by presenting its background, system structure, and webpage layouts and usage. The usage statistics of the site for the initial 3 months are also presented.

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Effects of soaking, stirring, and milling were investigated to standardize the washing method used for drill cutting samples. Drill cuttings are fragments of solid material ground by a drill bit at the bottom of a hole. They are recovered on the ship in riser drilling as a component of the circulating drilling mud. Removal of drilling mud from the surface of cutting samples must be done before cutting samples are analyzed. Cutting samples from IODP Expedition 337 were used in test experiments. The samples were analyzed before and after soaking, stirring, and milling with XRD, XRF, an elemental analyzer and a carbonate analyzer. Results show that Na and K contents are reduced by the removal of drilling mud. However, changes that occur after 6 h of soaking are rather minor. These results suggest that stirring of cuttings in heated seawater at 40℃ for 6 h after quick washing is effective for XRF and TOC analyses.

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