Horizontal PGV and intensity distribution (IMAGE) Science China Press Caption Horizontal PGV and intensity distribution under the four models, (a) the horizontal uniform stress model, and the self-similar stress model with (b) ac =50 km, (c) ac = 40 km, (d) ac =30 km, where ac is the characteristic length that determines the stress roughness. Credit ©Science China Press Usage Restrictions Use with credit. 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.