3.Research and development on land subsidence In the three cities,the total economic loss is about RMB$3.3 billion per year.The direct economic loss is about RMB$300 million per year and the related economic loss is RMB$30 billion per year.The exact economic loss due to land subsidence in Shanghai is not known yet(Wang and Zuo,1993).3. Research and development on land subsidence  In the three cities, the total economic loss is about RMB$3.3 billion per year. The direct economic loss is about RMB$300 million per year and the related economic loss is RMB$30 billion per year. The exact economic loss due to land subsidence in Shanghai is not known yet (Wang and Zuo, 1993)