Sumba island   has a great and unique position respect to the Sunda Banda archipelagoes, it is one of the biggest island on the East Nusa Tenggara region beside Flores and Timor. It represents an isolated sliver of probable continental crust to the south of active volcanic islands (Sumbawa, Flores ) within the forearc basin (Fig.1). It is situated to the north of passage from the Java Trench (subduction front) to the Timor Through (collision front). It does not show still the effects of strong compression in contrast to islands of the outer arc system (Savu, Roti, Timor), while the magmatic units make up a substantial part of the Late Cretaceous to Paleogene stratigraphy.

Sumba has a unique culture and their social life. Sumbanese are traditionally divided into three level of social life : (Raja/King) - Maramba,  Customary Official - Kabihu, and Slaves - Ata. Sumbanese are living from farming, cattle breeding, rice-field farming and trading. Ones owns cattle will contribute to their social status such as if they had more cattle giving them a higher social status.

Most Sumbanese are Christian (Catholic and Protestant), however, and part of them are still strongly keep their native and original religion called Marapu. Most cultural objects are related to the Marapu religion such as the shape of traditional houses, ceremonies, or kings' graves and tombs.

The Customary houses designed in high-peaked roof to store the heirlooms and store. It is divided into male and female section, and generally surrounded by impressive megalithic tombs. Their famous ceremony are the wedding and funerals. where they usually sacrificed animals pigs, buffaloes, cattle, and horses

HISTORY OF SUMBA ISLAND

According to an old myth the first humans came down to Sumba on a ladder from heaven and settled on Tanjung Sasar on the north side of the island. Another myth says that Umbu Walu Sasar, one of the two Sumbanese ancestors, was driven away from Java and brought to Sumba by the gods. He also settled on Tanjung Sasar. The other ancestor, Umbu Walu Mandoko, came by boat and settled on the east side. The fact is that the people here are a mix of Malay and Melanese, while the language is related to eastern Sumbawa, western Flores and Sawu. The death and burial ceremonies have significant similarities with Tana Toraja on Sulawesi.

Sumba was under control of the mighty Majapahit dynasty from Java in the 14th century. After Majapahit had fall, the island was ruled from Bima on Sumbawa and later Gowa on south Sulawesi. The society was however most influenced by the internal wars, even if there still was mutual economic dependency between the rival kingdoms. Horses, timber, betel nuts, rice, fruit and ikat were heavily traded between the various districts. The Dutch did not find any commercial possibilities here at first and paid little attention to Sumba before they started export of sandalwood in the 18th century. Before the discovery of penicillin sandalwood was the only known cure for venereal diseases, and was an expensive commodity that was exported to Europe, China and Arabic countries in large quantities. The trade was constantly interrupted by internal wars, and in 1906 the Dutch invaded Sumba and placed it under direct military rule. A civilian administration was set up in 1913 where the Dutch ruled through the reigning Sumbanese nobility. The native rulers were not accepted by Indonesia when the republic took control of the island in 1950, but many became government officials and in that way they and their families still have much influence