Tsunami vulnerability of buildings and people in South Java – field observations after the July 2006 Java tsunami

Abstract

Abstract.A team of scientists from New Zealand and Indonesia undertook a reconnaissance mission to the South Java area affected by the tsunami of 17 July 2006. The team used GPS-based surveying equipment to measure ground profiles and inundation depths along 17 transects across affected areas near the port city of Cilacap and the resort town of Pangandaran. The purpose of the work was to acquire data for calibration of models used to estimate tsunami inundations, casualty rates and damage levels. Additional information was gathered from interviews with eyewitnesses.The degree of damage observed was diverse, being primarily dependant on water depth and the building construction type. Water depths were typically 2 to 4 m where housing was seriously damaged. Damage levels ranged from total for older brick houses, to about 50% for newer buildings with rudimentary reinforced-concrete beams and columns, to 5-20% for engineered residential houses and multi-storey hotels with heavier RC columns. "Punchout" of weak brick walls was widespread. Despite various natural warning signs very few people were alerted to the impending tsunami. Hence, the death toll was significant, with average death and injury rates both being about 10% of the people exposed, for water depths of about 3 m.

Empirical fragility assessment of buildings affected by the 2011 Great East Japan tsunami using improved statistical models

“…These results are consistent with findings from previous studies evaluating tsunami damage (e.g. Ruangrassamee et al 2006;Reese et al 2007;Suppasri et al 2013a, b). In previous tsunami damage assessment studies, it was found that a tsunami flow depth of 2 m would be a significant threshold for the onset of collapse of a wooden building , as well as for collapse of masonry/brick type constructions (Yamamoto et al 2006).…”

Near-coast tsunami waveguiding: phenomenon and simulations

“…Tsunami heights and effects show a high variability along the coast, as has been observed in numerous field surveys that are reported in various journals and on websites (EERI (2005), Liu et al, 2005, Borrero et al, 2006, Synolakis and Kong, 2006, Reese et al, 2007. Numerical simulations of the effect of tsunamis on the coast are difficult and still rather inaccurate.…”

A multivariate generalized linear tsunami fragility model for Kesennuma City based on maximum flow depths, velocities and debris impact, with evaluation of predictive accuracy

“…Following the 2006 Java tsunami survey, Reese et al (2007) found robust buildings could act as a shield for weaker buildings, which would have typically suffered heavy damage from impacting debris. In the case of Kesennuma, it was not possible to directly quantify debris impact or the effects of sheltering from post-tsunami surveys, not only because of early debris removal by the authorities, but also because in the case of collapsed or washed away structures clear evidence of debris impact was not available.…”