Measuring land subsidence of buildings in Semarang Chinatown

Abstract

There are not many studies that discuss land subsidence and try to measure it in historic areas. This paper will take an inventory of historical areas that have existed since the early growth of cities such as Semarang Chinatown, which has existed since the 17th century. This paper is part of the results of research on land subsidence in coastal cities in Java, which have left many historical areas. Semarang City is one of the case studies because it has a high land subsidence rate of around 20 cm/year in the North Semarang area. Indeed, this area in the past was an ocean. However, due to sedimentation, on the old 1700s map, this area has become a marsh. After becoming mainland, several historical areas stood on young alluvial land. The purpose of this paper is to make an inventory of old buildings in the historic area of Chinatown. On the map from 1695 to now, after 305 years, the area has experienced land subsidence, which can be seen visually in several buildings. The research method used old photos, old maps, and field surveys by taking samples of several old residences that still exist. To strengthen the data, the use of Google street view is very helpful in seeing conditions in the field. The recommendation of this research is to provide directions for an inventory of the list of buildings that need to be conserved due to the hazard of subsidence, which is currently not being felt by the local community.