Simulations indicate that a tsunami sweeping east to west loses a lot of volume and force getting to the eastern end of the Sunda Strait. For example, a tsunami moving more or less southward through the Malacca Strait would likely do terrible damage to shipping in the strait, to both coasts of the strait and to Singapore, but in most scenarios the water just gets slowed too much by the land to continue its rampage as far south as Jakarta. A tsunami from the Gulf of Thailand or the southern portion of the South China Sea (the three arrows labelled with the letter ‘A’) would indeed blast several of the islands east of Sumatra and northeast of the Sunda Strait. The coastal areas of Java east of Jakarta generally get hammered, while the Jakarta metropolitan area can receive quite a spectrum of damages. For a tsunami moving east to west across the Java Sea (arrows labelled with the letter ‘B’) the most southerly portion of the eastern edge of Sumatra takes a beating. Jakarta again can receive quite a variety of damages. In most of these ‘B’ scenarios it is much more likely than in the ‘A’ scenarios that significant waves will transit the Sunda Strait (arrows labelled ‘C’).
Populstat gives the following historical estimates for the population of Jakarta, formerly known as Djakarta and Batavia, now known as the Special Capital Region of Jakarta (Indonesian: Daerah Khusus Ibu Kota Jakarta): 65,000 ; 99,100 ; 102,900 ; 97,000 [1882-3]; 100,500 ; and 105,100 . The current population of Jakarta is 10,075,310 (2014 estimate) and the population of the metropolitan area is 30,214,303.