Abstract：Based on in-situ monitoring data of seismic subsidence of loess induced by a short delay blasting，the distribution and development of seismic subsidence and their influencing factors in a loess site are studied. The observation results show that，during the whole experiment，the maximum seismic subsidence of loess in the test site reaches 33 mm while the maximum subsidence around the site attains to 26 mm. The both maximum values of subsidence are found at the south of the test field，which depend on the landform of this loess field，but seismic subsidence of loess decreases from the south to the north. On the other hand，the results indicate that after immediate explosion，the seismic subsidence of loess developed almost 50 percent of the maximum value of final loess subsidence，i.e. during the blasting process，seismic subsidence developed rapidly with the energy dissipation of explosives and then the increase of loess settlement in the field becomes slow and slow. According to the above-mentioned outcomes，it is believed that seismic subsidence could be induced in a loess site if there is a designed explosion with enough intensity occurring；and this in-situ test results could be an indirect example of loess seismic subsidence caused by an earthquake event in loess sites. These efforts make for a further understanding on the differences of loess seismic subsidence between laboratory and in-situ test results，and provide a basis for an empirical intensity design of explosive ground motion in practical engineering.
