 But one particularly dramatic example of the influence of human activity on earthquake ground shaking was during the 2018 earthquake in Palau Sulawesi and Indonesia. In this case there was a settlement built on relatively naturally occurring granular sediments in the Palau Valley. But in the past this had not been such a such a danger. That will enhance the shaking But but it was not normally associated with the phenomenon We call liquefaction where the soil once it's shaken up really loose granular soil if it's shaken up It can actually turn to liquid if there is water present if the water table is high and those sediments are saturated with fluid And that didn't happen until they dug out They made a big irrigation channel going up the Palau Valley and this irrigation channel it of course was used for irrigation So there was water poured on crops all in the valley and it also leaked a lot of water It wasn't a sealed channel so it leaked a lot of water out of the channel And so this really raised the water table in these granular sediments and made it a place that wasn't prone to liquefaction in the past Made it very prone to liquefaction now And so what we found was that there was a the liquefaction did occur and there were these huge Very every low angle like two degree slope Landslides so normally landslides occur on relatively sleep steep slips. These were very shallow slopes But still because the soil liquefied there was basically no resistance to it flowing the material flowing down these very shallow slips So you got these huge Slopes that these very shallow slopes in which landslides occurred over very large displacements The material just flowed over one and two kilometers distance and in the process Buried many people it destroyed many homes and buried many people