Figure 1 (IMAGE) Tohoku University Caption The lead author of this paper, Mochamad Riza Iskandar, deepened his research while at Tohoku University by discussing his findings with a number of experts at an international workshop. Credit Tohoku University's International Joint Graduate Program in Earth and Environmental Sciences Usage Restrictions Reporters may use freely these materials in news coverage with appropriate credit information. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.