Figure 2 (IMAGE) Tohoku University Caption Comparison of density‒velocity relations of iron at inner core conditions with Preliminary reference Earth model (PREM). The vp difference (A) and the vs difference (B) in the inner core. Credit Daijo Ikuta 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.