Field observations of the 17 July 2006 Tsunami in Java

Abstract

Abstract. The 17 July 2006, a tsunami struck the southern coast of Java, Indonesia, causing over 730 casualties. The triggering earthquake located 225 km off the coast of Pangandaran (9.222° S, 107.320° E), occurred at 15:19 LT (UTC +7) with a 7.7 magnitude on the Richter scale (Harward Center and CEA/DAM). In order to calibrate numerical models and understand the phenomenon, we conducted a 6-weeks field survey in July and August 2006 from Cimerak district in West Java to Gunung Kidul district in Central Java. Data collection involved measurements of wave height before its breaking, flow depth, run-up height, inundation depth, flow directions and a detailed chronology of the tsunami. Eyewitnesses accounted for three main waves. The maximum height of the second wave ranged from 4.2 to 8.6 m before its breaking. Maximum flow depth after the wave's breaking reached 5 m, and maximum runup heights reached 15.7 m. Our run-up values are about 1.5 higher than those obtained by the other field surveys carried out until present. They are also higher than the values computed through preliminary models. The 17 July 2006 tsunami has been generated by a "tsunami earthquake", i.e. an earthquake of low or medium scale that triggers a tsunami of high magnitude. The run-up heights progressively decreased eastwards, which is consistent with a tsunami triggered by fault dislocation, as the one that hit the Nicaragua's coast with similar run-up heights on the 2 September 1992. An earthquake with associated landslides could also have generated the 17 July 2006 tsunami, as ever observed in Papua-New-Guinea in 1998.

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

“…The fact that other teams did not measure water levels of this dimension in this area might argue for an overestimation. Our other levels are in line with the measurements from Lavigne et al (2007) and Tsuji et al (2007). Along the coast in the Pangandaran district the maximum water levels ranged from 3.3 m in the sheltered areas close to the Pangandaran peninsula, to 11.9 m in Pananjung Village (Fig.…”

“…Our other levels are in line with the measurements from Lavigne et al (2007) and Tsuji et al (2007).…”

“…These seem to correspond with the survey results from Lavigne et al (2007) and Tsuji et al (2007). Note also the very rapid decrease in water depth, from about 3 m to less than 1 m, in a distance of about 100 m.…”

Submarine landslides at the eastern Sunda margin: observations and tsunami impact assessment

“…Off Java and the Lesser Sunda Islands, devastating tsunamis were induced by the M w =8.3 Sumba earthquake of 1977, the eastern Java earthquake (M w =7.8) of 1994 and the M w =7.7 Pangandaran earthquake in 2006 (ITDB catalogue 2007). Maximum run-up values of respectively 8 m (Kato and Tsuji 1995), 14 m (Tsuji et al 1995a) and 20 m (Lavigne et al 2007;Fritz et al 2007) have been identified.…”

Landslide tsunami hazard in the Indonesian Sunda Arc

“…The largest were the M w =8.3 Sumba Earthquake of 1977, the East Java Earthquake (M w =7.8) of 1994 and the M w =7.7 Pangandaran Earthquake in 2006 (ITDB catalogue, 2007). Tsunami run-up reached 8 m (Kato and Tsuji, 1995), 14 m (Tsuji et al, 1995a) and 20 m (Lavigne et al, 2007;Fritz et al, 2007), respectively.…”