Effects of step changes in railway noise exposure and earthquakes on sleep disturbance

Abstract

In the areas spanning around 5 km north from Kumamoto Station (the northern area) and around 12 km south from the station (the southern area), Kyushu Shinkansen and conventional railway lines are closely parallel. After Kyushu Shinkansen Line was operated in 2011, the adjacent conventional railway line was elevated in the northern area, a new station was operated in the southern area, and large earthquakes struck Kumamoto area from March to April, 2016. Through socio-acoustic surveys from 2011 to 2017, sleep disturbances were compared between before and after the earthquakes per train type (Shinkansen and conventional train), area (north and south) and house type (detached and apartment). Sleep disturbance caused by Shinkansen railway for detached house in the northern area was significantly higher before than after the earthquakes. Sleep disturbance caused by Shinkansen railway for apartment house in the southern area was significantly higher after than before the earthquakes. The former may be caused by more frequently closing bed room windows of detached houses in the northern area. The latter was probably because Shinkansen trains slowed down just after the earthquakes and returned to the normal speed during the survey. There was no significant difference in the other six cases.