Morphologic Characteristics of the Vallis

Introduction: The Vallis Schröteri exists on the Aristarchus Plateau (305-313 °E, 22-30 °N) which is a topographic high surrounded by basaltic maria. The rille appears a singular sinuous rille as meandering primary rille including a more meandering inner rille. Typical sinuous rilles are 20 to 40 km in length and less than 1 km in width [1], however, the primary rille of Vallis Schröteri has been reported to be 125 km in length, up to 4.5 km in width, and 400 m in depth [2], and inner rille which is originated from the cobra-head of primary rille is reported to be ~170 km in length, 640 m of average width, and 95 m in depth [3]. The Vallis Schröteri exists on the highland which represents the crustal material of the Moon; so, the negative relief of this rille on the Aristarchus Plateau with no apparent levees and large width must be originated by the thermal and/or mechanical erosion of turbulent and sustained lava flow. We quantitatively define the physical properties of the turbulent lava flow to produce the Vallis Schröteri. The erosion rate into the substrate ground has been estimated by mod-eling of our turbulent lava flow. Our goal of this research is to evaluate the erosional effect of the em-placement of lunar lava flow, and to make variations of parameters such as effusion rate and volcanic temperature constrain by comparing our results of our modeling and actual morphology such as depth profile as a function of distance from vent-like feature. Data: The digital terrain model (DTM) is derived from the stereo pair of images of Terrain Camera (TC) with 10 m spatial resolution and 10 bits quantization on the Kaguya lunar satellite which was launched at the September, 2007. The TC has two cameras with slant angle of ± 15 °, so the base-height ratio observed from nominal 100 km altitude is 0.57. Consequently, the accuracy of DTM derived from the base-height ratio is 17 m [4]. Figure 1a, b show the mosaics of southern-west part of the Aristarchus Plateau and the DTM of same area. The mosaic data is orthorectified as the Transverse Mercator (TM). The value of height reveals the distance from the center of figuration of the Moon. We can recognize the whole of inner rille without hidden area by topographic shadow because of high incident angle of the sunlight (around 40 °). Morphology: The depth …