Tohoku University has developed dual sensor ALIS for humanitarian demining. ALIS is a system combining a GPR and a metal detector, and 2 sets of ALIS are used by CAMC (Cambodian Mine Action Center) since 2009 and one team is working with them and detected more than 80 mines. Data acquisition and interpretation under strong clutter conditions is very challenging for the use of GPR and metal detector in mine fields. We use SAR (Synthetic Aperture Radar) processing for GPR imaging and it is quite successful. Based on the experience of ALIS in Cambodia, we used sensor technology for survey activities in natural disasters. In September 2014, Ontake-san volcano in Nagano, Japan erupted and 58 were killed by fallen volcanic ash. We introduced a metal detector used for humanitarian demining to the local police and one victim could be found. We could prove that the function of a metal detector reducing the response from magnetic and metallic soil worked well. In 2015, we also introduced GPR for survey under the ash. In March 2011, the east part of Japan was attacked by a huge scale Tsunami and more than 15,000 were killed and still more than 2,500 are missing. We expect that many missing victims were flashed away by Tsunami and could be buried in sand in sand beaches or areas near the costs. We have worked together with local police stations and used metal detectors and multistatic GPR system “Yakumo” for the survey of Tsunami victims. In many beaches, we found that the semimetal layer of the Tsunami in 2011 is about 50-70cm thick, and could detect many objects buried under this sand layer. We think SAR processing in GPR is important for detecting small buried objects. We also demonstrate visualized metal detector sensors can be effectively used for survey in landslides.
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