Lesser Sunda Islands in the context of Subduction

Southeast Asia is the geographical southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of mainland Australia, which is part of Oceania. Southeast Asia is bordered to the north by East Asia, to the west by South Asia and the Bay of Bengal, to the east by Oceania and the Pacific Ocean, and to the south by Australia and the Indian Ocean. Apart from the British Indian Ocean Territory and two out of 26 atolls of the Maldives in South Asia, Maritime Southeast Asia is the only other subregion of Asia that lies partly within the Southern Hemisphere. Mainland Southeast Asia is entirely in the Northern Hemisphere. Timor-Leste and the southern portion of Indonesia are the parts of Southeast Asia that lie south of the equator.

The region lies near the intersection of geological plates, with both heavy seismic and volcanic activities. The Sunda plate is the main plate of the region, featuring almost all Southeast Asian countries except Myanmar, northern Thailand, northern Laos, northern Vietnam, and northern Luzon of the Philippines, while the Sunda plate only includes western Indonesia to as far east as the Indonesian province of Bali. The mountain ranges in Myanmar, Thailand, Peninsular Malaysia, and the Indonesian islands of Sumatra, Java, Bali, Lesser Sunda Islands, and Timor are part of the Alpide belt, while the islands of the Philippines and Indonesia as well as Timor-Leste are part of the Pacific Ring of Fire. Both seismic belts meet in Indonesia, causing the region to have relatively high occurrences of earthquakes and volcanic eruptions, particularly in the Philippines and Indonesia.

Bali (English: /ˈbɑːli/ ; Indonesian: ['bali]; Balinese: ᬩᬮᬶ) is a province of Indonesia and the westernmost of the Lesser Sunda Islands. East of Java and west of Lombok, the province includes the island of Bali and a few smaller offshore islands, notably Nusa Penida, Nusa Lembongan, and Nusa Ceningan to the southeast. The provincial capital, Denpasar, is the most populous city in the Lesser Sunda Islands and the second-largest, after Makassar, in Eastern Indonesia. The Denpasar metropolitan area is the extended metropolitan area around Denpasar. The upland town of Ubud in Greater Denpasar is considered Bali's cultural centre. The province is Indonesia's main tourist destination, with a significant rise in tourism since the 1980s, and has become the country's area of overtourism. Tourism-related business makes up 80% of the Bali economy.

Bali is the only Hindu-majority province in Indonesia, with 86.40% of the population adhering to Balinese Hinduism. It is renowned for its highly developed arts, including traditional and modern dance, sculpture, painting, leather, metalworking, and music. The Indonesian International Film Festival is held every year in Bali. Other international events that have been held in Bali include Miss World 2013, the 2018 Annual Meetings of the International Monetary Fund and the World Bank Group, and the 2022 G20 summit. In March 2017, Tripadvisor named Bali as the world's top destination in its Traveler's Choice award, which it earned once again in January 2021.

Lombok is an island in West Nusa Tenggara province, Indonesia. It forms part of the chain of the Lesser Sunda Islands, with the Lombok Strait separating it from Bali to the west and the Alas Strait between it and Sumbawa to the east. It is roughly circular, with a "tail" (Sekotong Peninsula) to the southwest, about 70 kilometres (43 miles) across and a total area of about 4,566.54 square kilometres (1,763.15 square miles) including smaller offshore islands. The provincial capital and largest city on the island is Mataram.

Lombok is somewhat similar in size and density, and shares some cultural heritage with the neighboring island of Bali to the west. However, it is administratively part of West Nusa Tenggara, along with the larger but less densely populated island of Sumbawa to the east. Lombok is surrounded by a number of smaller islands locally called Gili.

The Greater Sunda Islands (Indonesian and Malay: Kepulauan Sunda Besar) are four tropical islands situated within the Indonesian Archipelago, in the Pacific Ocean. The islands, Borneo, Java, Sulawesi and Sumatra, are internationally recognised for their ecological diversity and rich culture. Together with the Lesser Sunda Islands to their southeast, they comprise the archipelago known as the Sunda Islands.

Mainly part of Indonesia, each island is diverse in its ethnicity, culture and biological attributes. The islands have a long and rich history which has shaped their cultural backgrounds.

Timor (Indonesian: Pulau Timor; Portuguese: Ilha de Timor; Tetum: Illa Timór) is an island at the southern end of Maritime Southeast Asia, in the north of the Timor Sea. The island is divided between the sovereign states of Timor-Leste in the eastern part and Indonesia in the western part. The Indonesian part, known as West Timor, constitutes part of the province of East Nusa Tenggara. Within West Timor lies an exclave of Timor-Leste called Oecusse District. The island covers an area of 30,777 square kilometres (11,883 square miles). The name is a variant of timur, Malay for "east"; it is so called because it lies at the eastern end of the Lesser Sunda Islands. Mainland Australia is less than 500 km away, separated by the Timor Sea.

The Australasian realm is one of eight biogeographic realms that is coincident with, but not (by some definitions) the same as, the geographical region of Australasia. The realm includes Australia, the island of New Guinea (comprising Papua New Guinea and the Indonesian province of Papua), and the eastern part of the Indonesian archipelago, including the island of Sulawesi, the Moluccas (the Indonesian provinces of Maluku and North Maluku), and the islands of Lombok, Sumbawa, Sumba, Flores, and Timor, often known as the Lesser Sundas.

The Australasian realm also includes several Pacific island groups, including the Bismarck Archipelago, Vanuatu, the Solomon Islands, and New Caledonia. New Zealand and its surrounding islands are a distinctive sub-region of the Australasian realm. The rest of Indonesia is part of the Indomalayan realm. In the classification scheme developed by Miklos Udvardy, New Guinea, New Caledonia, Solomon Islands and New Zealand are placed in the Oceanian realm.

Jaco Island (Portuguese: Ilha de Jaco, Tetum: Illa Jako, Fataluku: Totina or Tontina) is an uninhabited island in Timor-Leste, a country occupying the eastern end of the island of Timor in the Lesser Sunda Islands in Southeast Asia. It lies off the eastern tip with Cape Cutcha of the island of Timor (Aldeia Pitileti, Suco Tutuala, administrative post Tutuala, municipality Lautém).

Rote Island (Indonesian: Pulau Rote, also called Roti) is an island of Indonesia, part of the East Nusa Tenggara province of the Lesser Sunda Islands. According to legend, this island got its name accidentally when a lost Portuguese sailor arrived and asked a farmer where he was. The surprised farmer, who could not speak Portuguese, introduced himself, "Rote". About 80% of the people of Rote Island in Indonesia are Christian. Christianity is an important part of the community.

Geologically, the Sunda Shelf (/ˈsʌndə/) is a south-eastern extension of the continental shelf of Mainland Southeast Asia. Major landmasses on the shelf include the Indonesian islands of Bali, Borneo, Java, Madura, and Sumatra, as well as their surrounding smaller islands. It covers an area of approximately 1.85 million km. Sea depths over the shelf rarely exceed 50 metres and extensive areas are less than 20 metres resulting in strong bottom friction and strong tidal friction. Steep undersea gradients separate the Sunda Shelf from the Philippines, Sulawesi, and the Lesser Sunda Islands (not including Bali).

Mount Tambora, or Tomboro, is an active stratovolcano in West Nusa Tenggara, Indonesia. Located on Sumbawa in the Lesser Sunda Islands, volcanism is the result of subduction zones. The 1815 eruption was the largest in recorded history, erupting up to 150 cubic kilometers of volcanic material, making it a VEI-7 on the Volcanic explosivity index. This caused the summer of 1816 to become known as the "Year Without a Summer" due to global cooling from the eruption.

Sumbawa, is an Indonesian island, located in the middle of the Lesser Sunda Islands chain, with Lombok to the west, Flores to the east, and Sumba further to the southeast. Along with Lombok, it forms the province of West Nusa Tenggara, but there have been plans (currently held in abeyance) by the Indonesian government to split the island off into a separate province. Traditionally, the island is known as the source of sappanwood, as well as honey and sandalwood. Its savanna-like climate and vast grasslands are used to breed horses and cattle, as well as to hunt deer.

Sumbawa has an area of 15,448 square kilometres or 5,965 square miles (three times the size of Lombok) with a population (at the 2020 Census) of 1,561,461; the official estimate as at mid-2024 was 1,669,787. It marks the boundary between the islands to the west, which were influenced by religion and culture spreading from India, and the region to the east which was less influenced. In particular, this applies to both Hinduism and Islam. While the name "Sumbawa" is used by outsiders for the whole island, locally the term is only applied to the western half (Sumbawa and West Sumbawa Regencies), while the eastern half is referred to by inhabitants as "Bima" (meaning the city as well as Bima and Dompu Regencies), as the two parts of the island are divided by geography, culture and language.

The wild boar (Sus scrofa), also known as the wild swine, common wild pig, Eurasian wild pig, or simply wild pig, is a suid native to much of Eurasia and North Africa, and has been introduced to the Americas and Oceania. The species is now one of the widest-ranging mammals in the world, as well as the most widespread suiform. It has been assessed as least concern on the IUCN Red List due to its wide range, high numbers, and adaptability to a diversity of habitats. It has become an invasive species in part of its introduced range. Wild boars probably originated in Southeast Asia during the Early Pleistocene and outcompeted other suid species as they spread throughout the Old World.

As of 2005, up to 16 subspecies are recognized, which are divided into four regional groupings based on skull height and lacrimal bone length. The species lives in matriarchal societies consisting of interrelated females and their young (both male and female). Fully grown males are usually solitary outside the breeding season. The wolf is the wild boar's main predator in most of its natural range except in the Far East and the Lesser Sunda Islands, where it is replaced by the tiger and Komodo dragon respectively. The wild boar has a long history of association with humans, having been the ancestor of most domestic pig breeds and a big-game animal for millennia. Boars have also re-hybridized in recent decades with feral pigs; these boar–pig hybrids have become a serious pest wild animal in the Americas and Australia.

The Kangean Islands, also known as the Kangean Archipelago (Kangean: Kapoloan Kangayan) are the group of islands within the Lesser Sunda Islands complex of Indonesian Archipelago located in the northern Bali Sea. It comprises a total of 118 islands (27 inhabited islands), with the Kangean Island as the main and biggest island in the region.

Eastern Indonesia (or East Indonesia; Indonesian: Indonesia Timur, pronounced [ɪndoˌnes(i)ja ˈt̪imʊr]) is one of the two main geographical regions of Indonesia, the other being Western Indonesia. It comprises four geographical units: Lesser Sunda Islands, Sulawesi, Maluku Islands and Papua. Central Indonesian Time and Eastern Indonesia Time are the national standard time designated for Eastern Indonesia; it falls within the UTC+8 and UTC+9 time zone, respectively.

Eastern Indonesia borders the Southern Philippines and Palau in the North, Papua New Guinea in the East, and Northern Australia in the South.

The Kingdomship of Bali (Balinese: ᭚ᬓᭂᬭᬚ᭡ᬦ᭄ᬩᬮᬶ; romanized: Kĕrajaan Bali) was a series of Hindu-Buddhist kingdoms that once ruled some parts of the volcanic island of Bali, in Lesser Sunda Islands, Indonesia. With a history of native Balinese kingship spanning from the early 10th to early 20th centuries, Balinese kingdoms demonstrated sophisticated Balinese court culture where native elements of spirit and ancestral reverence combined with Hindu influences—adopted from India through ancient Java intermediary—flourished, enriched and shaped Balinese culture.

Because of its proximity and close cultural relations with the neighbouring island of Java during the Indonesian Hindu-Buddhist period, the history of the Bali Kingdom was often intertwined with and heavily influenced by its Javanese counterparts, from Mataram (c. 9th century) to the Majapahit empire in the 13th to 15th centuries. The culture, language, arts and architecture of the island was influenced by Java. Javanese influences and presences grew even stronger with the fall of the Majapahit empire in the late 15th century. After the empire fell to its Muslim vassal the Demak Sultanate, a number of Hindu Majapahit courtiers, nobles, priests, and artisans found refuge on the island of Bali. As a result, Bali became what historian Ramesh Chandra Majumdar describes as the last stronghold of Indo-Javanese culture and civilisation. The Bali Kingdom in the following centuries expanded its influence to neighboring islands and began to establish colonies; Gelgel Kingdom Bali, for example, expanded their influence and established a colony in the Blambangan region at the eastern tip of Java to the western part of the Sumbawa island, while Karangasem Kingdom established their colonial settlements in western parts of Lombok, and the Klungkung kingdom conquered Nusa Penida in a later period.

Nusa Lembongan (Balinese: ᬦᬸᬲ​ᬮ᭄ᬮᭂᬫ᭄ᬩᭀᬗᬦ᭄, romanized: nusa lĕmbongan) is an island located southeast of Bali, Indonesia. It is part of a group of three islands that make up the Nusa Penida District in Klungkung Regency, of which it is the most famous of the three islands of Nusa Penida, Nusa Lembongan, and Nusa Ceningan - known together as the "Nusa Islands". This island group, in turn, is part of the Lesser Sunda Islands.

Denpasar (Indonesian pronunciation: [denˈpasar]; Balinese: ᬤᬾᬦ᭄ᬧᬲᬃ, Dénpasar) is the capital and the largest city of the province of Bali, Indonesia.Denpasar is the largest city in the Lesser Sunda Islands and the second largest city in Eastern Indonesia after Makassar. It is bordered by Badung Regency to its west, Gianyar Regency to its east, and the Indian Ocean and the Badung Strait to its south. The growth of the tourism industry on the island of Bali has pushed the city of Denpasar to become a center of business activities, and has positioned the city as an area with high per capita income and growth in Bali. The population of the City at the end of 2024 was 670,210.

Denpasar is the main gateway to the Bali island, the city is also a hub for other cities in the Lesser Sunda Islands.

The Denpasar metropolitan area or Greater Denpasar, and locally known as Sarbagita; (an acronym of Denpasar–Badung–Gianyar–Tabanan) is a metropolitan area located in Bali, Indonesia. This area includes Denpasar city and its surrounding areas such as Badung Regency, Gianyar Regency, and Tabanan Regency. Sarbagita is the largest metropolitan area in the Lesser Sunda Islands and the second largest in the Eastern Indonesia region after the Makassar metropolitan area in South Sulawesi. It has an area of 1,928.28 km, and at the 2023 estimate had a population of 2,301,887.

West Nusa Tenggara (Indonesian: Nusa Tenggara Barat, NTB; pronounced [ˌnusa t̪əŋˌɡara ˈbarat̪̚], lit. 'West Southeast Islands') is a province of Indonesia. It comprises the western portion of the Lesser Sunda Islands, with the exception of Bali which is its own province. The area of this province is 19,890.31 km (7,679.69 sq mi) which consists of two main islands, namely Lombok Island and Sumbawa Island as well as several other small islands. The two largest islands in this province are the smaller but much more populated Lombok in the west and the much larger in area but much less densely populated Sumbawa island in the east. Mataram, on Lombok, is the capital and largest city of the province. It shares maritime borders with Bali to the west and East Nusa Tenggara to the east.

Geographically, West Nusa Tenggara is divided into a flat coastal area, especially in western and southern Lombok, and a mountainous area that includes Mount Rinjani, the highest mountain in the province at 3,726 meters, which is also an active volcano and one of the most popular natural tourist destinations. On Sumbawa Island, the landscape is more varied with steeper hills and mountains and dry grasslands in the east.