Indonesia has experienced severe tropical forest fires from a long time ago, mainly in El Niño years.However, previous studies showed that after 1997 forest and peat fires in Indonesia tend to occur every year in the dry season, even in non El Niño years. To clarify this recent pattern of incidence, we studied the fire situation in the Mega Rice Project (MRP) area, Central Kalimantan where large scale development of tropical swamp-forest has been carried out since 1996. To identify the causes of the recent severe peat fires, weather data for Palangkaraya from 1978 to 2007, hotspot data captured by the MODIS satellite, monthly Niño 3.4 sea surface temperature (SST) anomalies, and ground water level (GWL) data were analyzed.The results of the analysis clearly showed a relationship among the precipitation pattern of the dry season, GWL change, Niño 3.4 SST Anomalies, and fire occurrences. A pattern of low precipitation in the dry season decreased GWL and caused a peat fire peak in the middle of August when daily precipitation reached the minimum. These results suggest that large areas of bared peat in the MRP now has a high susceptibility to fire coupled with the precipitation pattern of the dry season.

In this study, changes in the pore water pressure were observed for saturated specimens of a loose fined-grain sand (Nam O sand) and a soft silty clay (Hue clay) subjected to undrained cyclic shearing with different testing conditions. The cyclic shear tests were run for relatively wide range of shear strain amplitude (g = 0.05%-2%), different cycle numbers (n = 10, 50, 150 and 200) and various shear directions (uni-direction and two-direction with phase difference of q = 0o, 45o and 90o). It is indicated from the experimental results that under the same cyclic shearing condition, the pore water pressure accumulation in Hue clay is at a slower rate, suggesting a higher cyclic shear resistance of Hue clay than that of Nam O sand. Liquefaction is reached easily in nominally 50% relative density specimens of Nam O sand when g ³ 0.4%, meanwhile soft specimen of Hue clay is not liquefied regardless of the cyclic shearing conditions used in this study. The threshold number of cycles for the pore water pressure generation generally decreases with g meanwhile, the threshold cumulative shear strain for such a property mostly approaches 0.1%. In addition, by using this new strain path parameter, it becomes more advantageous when evaluating the pore water pressure accumulation in Nam O sand and Hue clay subjected to undrained uni-directional and two-directional cyclic shears.

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