Why is it that maritime islands in Southeast Asia have peculiar landforms?

Question

Why is it that maritime islands in Southeast Asia have peculiar landforms?

Answer 1

Islands in South Est Asia number in tens of thousands of all sizes.

They are composed of 2 clusters. Philippines to the North (and a bit to East) is compact, unlike the East-West sprawl of Sulu (Indonesian) Archipelago.

Biggest are

1. New Guinea (2nd largest behind 'Greenland' the largest, Eastern half is the country 'Papuanugini' & Western half is in Indoneasia)

2. Borneo (3rd largest; Northern third is split p between Malaysia and the tiny kingdom of 'Brunei' & southern part is in indonesia)

3. Sumatra (6th)

4. Sulawesi (11th)

5. Java (13th)

6. Luzon (17th; Philippines)

7. Mindanao (19th: Philippines)

There are mid-sized ones (in decreasing order):

Timor, Halmahera, Ceram, Flores, Sumbawa in Sulu group and Samar, Ne gros, Palawan in Philippines group.

All islands are rocky, forming a submerged mountain chain. Where land is above sea level it forms islands. Individual mountain spurs jut out like fingers above water. Except the rounded Borneo, most islands are long. Sumatra may be the second longest Island (or equal in length to the fourth largest Madagascar) after Greenland. Of the whole lot 'Sulawesi' has a unique 'K' shape with an added flourish and 'Halmahera' is similar (K) to a lesser degree.  All islands are volcanic.

Answer 2

Because of past violent earthquakes, and present typhoons.