Volume 118 (2009) Issue 3 Pages 492-498
We examine the possible effect of shaking from the May 26, 2006 Yogyakarta earthquake (MW6.3) on the triggering of the Sidoarjo, Indonesia mud volcano, which is located about 250 km from the earthquake. The mud volcano has been erupting since May 2006. There seems to be indications from the timing of pressure changes in the neighborhood of the mud volcano and the earthquake occurrence, that the seismic waves may have affected the local fluid conditions. The level of stress changes from the earthquake waves is inferred from data of other similar sized earthquakes. The stress changes are quite small (0.005 to 0.010 MPa), but in the range of values that have triggered small earthquakes in other regions. There appeared to be pressure changes in the well drilling several minutes after the earthquake, suggesting a fluid response to the earthquake shaking. Although it seems possible that the 2006 Yogyakarta earthquake triggered small fluid pressure changes at the mud volcano, it is difficult to evaluate if there is any direct relation to the initiation of the mud eruption.