and volcanic deposits from Merapi (sand, agglomerates, tuff, and ash), as well as limestone and sandstone. Borehole and magnetic data surveys show that the alluvium and lahar deposits at the Bantul graben are thick and at places over 200 meters, and the water table is below ground level. Most liquefaction events took place near the wide Opak Fault zone. Sand boils, lateral spreading, settling, and slides led to some tilting and collapse of buildings. Damage Altogether, eleven densely populated districts comprising 8.3 million people were affected, but the regencies of Bantul, Sleman, Gunung Kidul, Kulon Progo, Klaten, and the city of Yogyakarta were especially hard hit. More than 5,700 people were killed in the early morning shock, with tens of thousands injured, and hundreds of thousands made homeless. Total financial losses from the event are estimated to be Rp 29.1 Trillion ($3.1B), with 90% of the damage affecting the private sector (homes and private businesses) and only 10% affecting the public sector. The damage to housing accounted for about half of the total losses and a comparison was made to the damage to homes in Aceh following the 2004 Indian Ocean earthquake and tsunami. Damage in central Java was more pronounced because of the substandard construction practices and the high population density, but on the other end of the scale, damage to infrastructure was very limited. Housing With 154,000 houses destroyed and 260,000 units experiencing damage, the event was one of the most costly natural disasters in the previous ten years. With 7% of housing units lost, more houses were damaged than during the 2004 Sumatra–Andaman and the 2005 Nias–Simuele events combined. With 66,000 homes destroyed, the Klaten District saw the heaviest damage, followed by Bantul, with 47,000 destroyed. In the most heavily damaged areas, 70–90% of units destroyed, contributing to a total of 4.1 million cubic meters of debris. Of the three home construction styles used in the area, the most common type fared badly. Low quality materials and improper construction styles led to unreinforced masonry buildings being responsible for the large loss of life and the high number of injuries. The Earthquake Engineering Research Institute stated that there was a "lack of wall integrity in the transverse direction for out-of-plane forces" and "no mechanical connection between the top of the wall and the roof or floor, and inadequate out-of-plane strength due to a lack of reinforcement". Prambanan The