Derawan Islands

The Derawan Islands are in the province of East Kalimantan in Indonesia. They include Derawan, Sangalaki, Kakaban, Maratua, Panjang, and Samama Island and submerged reefs and islets. They are located in the Sulawesi Sea, on the coastal shelf of East Kalimantan (2°17′N - 118°13′E). The islands are part of the Berau Regency.

Biodiversity
Derawan islands is a part of Coral Triangle, which contains one of the richest marine biodiversity on earth. Located in a biodiversity hotspot, the Derawan Islands feature 872 species of reef fishes, 507 species of coral, and invertebrates, including protected species (5 giants clam species, 2 sea turtles, coconut crab, etc.). Some of the islands harbor the heavily exploited turtle eggs and yet the largest green turtle nesting site in Indonesia.

Unpoisoned jellyfish
Derawan Islands have at least two ponds contain unpoisoned jellyfish, one in Kakaban Island and the other in Maratua Island with Haji Buang Pond. Kakaban is more famous than the second which is also more difficult to access. Indonesia at least have 7 ponds with unpoisoned jellyfish, the others are 3 ponds in Raja Ampat, West Papua, one in Togean Island, Central Sulawesi and one in Rote Island, East Nusa Tenggara.

Resources Use
There are two inhabited islands, namely Derawan (1 village of 1,259 people) and Maratua (4 villages of 2,704 people). Fishing is an important income-generating activity for the community. Since the early 1990s, people have caught live groupers, napoleon wrasse, and lobsters, to fill high demand. There are 3 dive resorts on Derawan Islands, while more additional resorts or facilities are in the planning process.

Caves
Maratua Island is 384.36 square kilometers and has at least 13 caves, but the prediction, more than a hundred caves are not yet explored. The caves usually have connection directly to the sea due to the caves are originated from the reef which sea water infiltrates into the land making underground channels.

Airport and seaport
To boost tourism, local government will build an airport and a seaport at Maratua Island and both were predicted to operate in 2013. World Wildlife Fund and environmental activists are opposing it because the construction of the projects will surely affect the turtle habitat and coral reefs on Maratua Island, but the local government apparently focuses more on development projects instead of conservation.

Mount Bromo

Mount Bromo is an active volcano and part of the Tengger massif, in East Java, Indonesia. At 2,329 metres (7,641 ft) it is not the highest peak of the massif, but is the most well known. The massif area is one of the most visited tourist attractions in East Java, Indonesia. The volcano belongs to the Bromo Tengger Semeru National Park. The name of Bromo derived from Javanese pronunciation of Brahma, the Hindu creator god. Sulfur is collected from inside the caldera by workers.
Mount Bromo sits in the middle of a vast plain called the "Sea of Sand" (Javanese: Segara Wedi or Indonesian: Lautan Pasir), a protected nature reserve since 1919. The typical way to visit Mount Bromo is from the nearby mountain village of Cemoro Lawang. From there it is possible to walk to the volcano in about 45 minutes, but it is also possible to take an organised jeep tour, which includes a stop at the viewpoint on Mount Penanjakan (2,770 m or 9,088 ft) (Indonesian: Gunung Penanjakan). The viewpoint on Mount Penanjakan can also be reached on foot in about two hours.
Depending on the degree of volcanic activity, the Indonesian Centre for Volcanology and Disaster Hazard Mitigation sometimes issues warnings against visiting Mount Bromo.

Culture
On the fourteenth day of the Hindu festival of Yadnya Kasada, the Tenggerese people of Probolinggo, East Java, travel up the mountain in order to make offerings of fruit, rice, vegetables, flowers and sacrifices of livestock to the mountain gods by throwing them into the caldera of the volcano. The origin of the ritual lies in the 15th century legend where a princess named Roro Anteng started the principality of Tengger with her husband, Joko Seger. The couple were childless and therefore beseeched the assistance of the mountain gods. The gods granted them 24 children but stipulated that the 25th child, named Kesuma, must be thrown into the volcano as a human sacrifice. The gods' request was implemented. The tradition of throwing sacrifices into the volcano to appease these ancient deities continues today and is called the Yadnya Kasada ceremony. Though fraught with danger, some locals risk climbing down into the crater in an attempt to recollect the sacrificed goods that they believe could bring them good luck.
On the Segara Wedi sand plain sits a Hindu temple called Pura Luhur Poten. The temple holds a significant importance to the Tenggerese scattered across the mountain villages, such as Ngadisari, Wonokitri, Ngadas, Argosari, Ranu Prani, Ledok Ombo and Wonokerso. The temple organises the annual Yadnya Kasada ceremony which lasts for about one month. On the 14th day, the Tenggerese congregate at Pura Luhur Poten to ask for blessings from Ida Sang Hyang Widi Wasa and the God of Mahameru (Mount Semeru). Then the crowd proceeds along the crater edges of Mt Bromo where offerings are thrown into the crater. The major difference between this temple and Balinese ones are the type of stones and building materials. Pura Luhur Poten uses natural black stones from volcanoes nearby, while Balinese temples are mostly made from red bricks. Inside this pura, there are several buildings and enclosures aligned in a mandala zone composition.

Activity
2004 eruptions
Mount Bromo erupted in 2004. That eruptive episode led to the death of two people who had been hit by rocks from the explosion.
2010 eruptions
On Tuesday, 23 November 2010, 16.30 WIB (Western Indonesian Time), the Indonesian Centre of Vulcanology and Geology Hazard Mitigation (CVGHM) confirmed the activity status of Mount Bromo at "alert" due to increasing tremor activity and shallow volcanic earthquakes at the mountain. Concerns were raised that a volcanic eruption might be likely to occur. As a precaution local residents and tourists were instructed to remain clear of an area within a radius of three kilometres from the caldera and refugee encampments were erected. The area surrounding the Teggera caldera of Bromo remained off-limits for visitors throughout the remainder of 2010.
Bromo started to erupt ash on Friday 26 November 2010.
On 29 November 2010 Transport Ministry spokesman Bambang Ervan announced that Malang's domestic airport would be closed until 4 December 2010. Malang is a city of about 800,000 people is about 25 km (16 mi) west of Mount Bromo. Abdul Rachman Saleh Airport normally handles 10 daily domestic flights from the capital Jakarta. Government volcanologist Surono reported that the volcano was spitting columns of ash some 700 metres (2,300 feet) into the sky.

Mount Rinjani

Mount Rinjani or Gunung Rinjani is an active volcano in Indonesia on the island of Lombok. Administratively the mountain is in the Regency of North Lombok, West Nusa Tenggara (Indonesian: Nusa Tenggara Barat, NTB). It rises to 3,726 metres (12,224 ft), making it the second highest volcano in Indonesia.
On the top of the volcano is a 6-by-8.5-kilometre (3.7 by 5.3 mi) caldera, which is filled partially by the crater lake known as Segara Anak or Anak Laut (Child of the Sea) due to blue color of water lake as Laut (Sea). This lake is approximately 2,000 metres (6,600 ft) above sea level and estimated to be about 200 metres (660 ft) deep; the caldera also contains hot springs. Sasak tribe and Hindu people assume the lake and the mount are sacred and some religious activities are occasionally done in the two areas. On 31 October 2015, Mount Rinjani started erupting again.

Geography
Lombok is one of the Lesser Sunda Islands, a small archipelago which, from west to east, consists of Bali, Lombok, Sumbawa, Flores, Sumba and the Timor islands; all are located at the edge of the Australian continental shelf. Volcanoes in the area are formed due to the action of oceanic crusts and the movement of the shelf itself. Rinjani is one of at least 129 active volcanoes in Indonesia, four of which belong to the volcanoes of the Sunda Arc trench system forming part of the Pacific Ring of Fire – a section of fault lines stretching from the Western Hemisphere through Japan and South East Asia. The islands of Lombok and Sumbawa lie in the central portion of the Sunda Arc. The Sunda Arc is home to some of the world's most dangerous and explosive volcanoes. The eruption of nearby Mount Tambora on Sumbawa is known for the most violent eruption in recorded history on 15 April 1815, with a scale 7 on the VEI.
The highlands are forest clad and mostly undeveloped. The lowlands are highly cultivated. Rice, soybeans, coffee, tobacco, cotton, cinnamon, cacao, cloves, cassava, corn, coconuts, copra, bananas and vanilla are the major crops grown in the fertile soils of the island. The slopes are populated by the indigenous Sasak population. There are also some basic tourist related activities established on Rinjani primarily in or about the village of Senaru.
Rinjani volcano on the island of Lombok rises to 3,726 metres (12,224 ft), second in height among Indonesian volcanoes only to Sumatra's Kerinci volcano. Rinjani has a steep-sided conical profile when viewed from the east, but the western side of the compound volcano is truncated by the 6 x 8.5 km, oval-shaped Segara Anak caldera. The western half of the caldera contains a 230-metre-deep lake whose crescentic form results from growth of the post-caldera cone Barujari at the eastern end of the caldera.

Geologic summary
On the basis of plate tectonics theory, Rinjani is one of the series of volcanoes built in the Lesser Sunda Islands due to the subduction of Indo-Australian oceanic crust beneath the Lesser Sunda Islands, and it is interpreted that the source of melted magma is about 165–200 kilometres (103–124 mi) depth.
The geology and tectonic setting of Lombok (and nearby Sumbawa) are described as being in the central portion of the Sunda Arc. The oldest exposed rocks are Miocene, suggesting that subduction and volcanism began considerably later than in Java and Sumatra to the west, where there are abundant volcanic and intrusive rocks of Late Mesozoic age. The islands are located on the eastern edge of the Sunda shelf, in a zone where crustal thickness is apparently rapidly diminishing, from west to east.
The seismic velocity structure of the crust in this region is transitional between typical oceanic and continental profiles and the Mohorovičić discontinuity (Moho) appears to lie at about 20 kilometres (12 mi) depth. These factors tend to suggest that there has been limited opportunity for crustal contamination of magmas erupted on the islands of Lombok and Sumbawa. In addition, these islands lie to the west of those parts of the eastern-most Sunda and west Banda arcs where collision with the Australian plate is apparently progressing.
The volcano of Rinjani is 165 to 190 kilometres (103–118 mi) above the Benioff Zone. There is a marked offset in the line of active volcanoes between the most easterly Sumbawa volcano (Sangeang Api) and the line of active volcanoes in Flores. This suggests that a major transcurrent fault cut across the arc between Sumbawa Island and Flores. This is considered to be a feature representing a major tectonic discontinuity between the east and west Sunda Arcs (the Sumba Fracture). Further, a marked absence of shallow and intermediate earthquake activity in the region to the south of Lombok and Sumbawa is a feature interpreted to represent a marked break in the Sunda Arc Zone. Faulting and folding caused strong deformation in the eastern part of Lombok Basin and is characterized by block faulting, shale diapirs and mud volcano.

Volcanology
The Rinjani caldera forming eruption is thought to have occurred in the 13th century. Dated to "late spring or summer of 1257," this eruption is now considered the likely source of high concentrations of sulfur found in widely dispersed ice core samples and may have been "the most powerful volcanic blast since humans learned to write." The massive eruption may have triggered an episode of global cooling and failed harvests.
Eruption rate, eruption sites, eruption type and magma composition have changed during the last 10,000 years before the caldera forming eruption. The eruptions of 1994 and 1995 have presented at Gunung Baru (or 'New Mountain' - approximately 2,300 metres (7,500 ft) above sea level) in the center of this caldera and lava flows from subsequent eruptions have entered the lake. This cone has since been renamed Gunung Barujari (or 'Gunung Baru Jari' in Indonesian).
The first historical eruption occurred in September 1847. The most recent eruption of Mount Rinjani was in May 2010 and the most recent significant eruptions occurred during a spate of activity from 1994 to 1995 which resulted in the further development of Gunung Barujari. Historical eruptions at Rinjani dating back to 1847 have been restricted to Barujari cone and the Rombongan dome (in 1944) and consist of moderate explosive activity and occasional lava flows that have entered Segara Anak lake. The eruptive history of Rinjani prior to 1847 is not available as the island of Lombok is in a location that remained very remote to the record keeping of the era.
On 3 November 1994, a cold lahar (volcanic mudflow) from the summit area of Rinjani volcano traveled down the Kokok Jenggak River killing thirty people from the village of Aikmel who were caught by surprise when collecting water from the river in the path of the flow.
In connection with the eruption of the cone Gunung Barujari the status for Gunung Rinjani has been raised from Normal (VEI Level 1) to 'be vigilant' (VEI Level 2) since May 2, 2009 . In May 2010 Gunung Rinjani was placed in the standby status by Center for Volcanology & Geological Hazard Mitigation, Indonesia with a recommendation that there be no activity within a radius of 4 kilometres (2.5 mi) from the eruption at Gunung Barujari.

Maluk Beach

Maluk Beach is one of stunning beaches in Sumbawa Island. The color of the sun will change becomes golden gradually at sunset, and it will give beautiful panorama. You can just relax or sit on fine sand while shipping your tea. Just like other beaches in Indonesia, it has white and soft sand. The pristine water seems invite you to swim or snorkel. Enjoying the wave of water is also one of attractive thing you can do when you visit the beach. For most surfers, the wave of Maluk is powerful and strong.

Location
Maluk Beach is located at a peninsula. Precisely, the beach is situated at Maluk Jereweh Village, West Sumbawa Regency, West Nusa Tenggara, Indonesia. Because the beach is flanked by two hills, Mantun Hill at the north, and Balas Hill at the south, it makes Maluk has wonderful panorama. You can start you journey from Benete Terminal. You can hire a motorcycle, take ojek to Maluk beach. You only need to pay IDR2,000 or US$0.2.
The cost is cheap because you only need to go for 1.5 km. Differently, if you want to hire a motorcycle, you only need to pay IDR100,000 per day, or US$10. By hiring a motorcycle, you will be free and have more time to get more spots in Maluk Beach. The good thing about Maluk Beach is you don’t need to buy a ticket.


Activities
There are many things you can do when you visiting Maluk Beach. First, you can see conservation of turtle. In this place, you will see the eggs of turtles, or even the baby of turtle. If you lucky, you can release the baby of turtle into the beach. However, the most favorite activity in the beach is surfing. Surfers from around the world love the wave in the beach because it is strong and powerful, especially when the tide is high.
The high of wave can be 4 – 6 meters. If you want to challenge your adrenaline, this is one of thing you can do in Maluk Beach. But, if you want to relax and enjoy the day, you can just lie down on white sand. From the distance, you can see other visitors canoeing or swimming.
There are many food stalls offering sea food along the beach. The traditional culinary around here is special because it made by traditional ingredients. As the source of seafood, fishermen provide fresh fishes, lobsters, and crabs. The most favorite dish is named as spicy dendeng.


According the report of local government, West Sumbawa has dozens of surfing spots. Even, there are surfers gave three names main beaches, i.e. Sekongkang, Maluk and Njlenga. These spots are well known as golden triangle. That is mean the real surfers should visit these surfing spots. With those qualities, that makes the three of these beaches become the spot of international competition of surfing. The participants come from many countries, such as Philippine, Australia, New Zealand, and Indonesia.

Accommodations
The facilities and accommodations in Maluk Island are complete. There are many home stay and hostel. These guesthouses are simple you can rest while accompanied by sound of water at night.
Or, you can start the journey from Mataram – Lombok. Then, you can continue to the port to cross the sea for 22 km. You have to wait a ferry and it will take around 2 hours to arrive at Poto Tano Port in West Sumbawa. If you want to go to Taliwang and Njlenga, it will take 2.5 hours, and to Maluk Beach, it will take 3.5 hours.

Lake Toba

Lake Toba  is a large natural lake occupying the caldera of a supervolcano. The lake is about 100 kilometres long, 30 kilometres wide, and up to 505 metres (1,666 ft) deep. Located in the middle of the northern part of the Indonesian island of Sumatra, with a surface elevation of about 900 metres (2,953 ft), the lake stretches from 2.88°N 98.52°E to 2.35°N 99.1°E. It is the largest lake in Indonesia and also the largest volcanic lake in the world.

Lake Toba is the site of a massive supervolcanic eruption estimated at VEI 8 that occurred 69,000 to 77,000 years ago, representing a climate-changing event. It is the largest known explosive eruption on Earth in the last 25 million years. According to the Toba catastrophe theory, it had global consequences for human populations: it killed most humans living at that time and is believed to have created a population bottleneck in central east Africa and India, which affects the genetic make up of the human world-wide population to the present.

It has been accepted that the eruption of Toba led to a volcanic winter with a worldwide decrease in temperature between 3 to 5 °C (5.4 to 9.0 °F), and up to 15 °C (27 °F) in higher latitudes. Additional studies in Lake Malawi in East Africa show significant amounts of ash being deposited from the Toba eruptions, even at that great distance, but little indication of a significant climatic effect in East Africa.

Geology
The Toba caldera complex in Northern Sumatra, comprises four overlapping volcanic craters that adjoin the Sumatran "volcanic front." The fourth and youngest caldera is the world's largest Quaternary caldera (100 by 30 km (62 by 19 mi)) and intersects the three older calderas. An estimated 2,800 km3 (670 cu mi) of dense-rock equivalent pyroclastic material, known as the youngest Toba tuff, was released during one of the largest explosive volcanic eruptions in recent geological history. Following this eruption, a resurgent dome formed within the new caldera, joining two half-domes separated by a longitudinal graben.

At least four cones, four stratovolcanoes, and three craters are visible in the lake. The Tandukbenua cone on the northwestern edge of the caldera has only sparse vegetation, suggesting a young age of several hundred years. Also, the Pusubukit (Hill Center) volcano (1971 metres above sea level) on the south edge of the caldera is solfatarically active and is a Geology Sanctuary.

Flora and fauna
The flora of the lake includes various types of phytoplankton, emerged macrophytes, floating macrophytes, and submerged macrophytes, while the surrounding countryside is rainforest including areas of Sumatran tropical pine forests on the higher mountainsides.

The fauna includes several species of zooplankton and benthic animals. Since the lake is oligotrophic (nutrient-poor), the native fish fauna is relatively scarce, and the only endemics are Rasbora tobana (strictly speaking near-endemic, since also found in some tributary rivers that run into the lake) and Neolissochilus thienemanni, locally known as the Batak fish. The latter species is threatened by deforestation (causing siltation), pollution, changes in water level and the numerous fish species that have been introduced to the lake. Other native fishes include species such as Aplocheilus panchax, Nemacheilus pfeifferae, Homaloptera gymnogaster, Channa gachua, Channa striata, Clarias batrachus, Barbonymus gonionotus, Barbonymus schwanenfeldii, Danio albolineatus, Osteochilus vittatus, Puntius binotatus, Rasbora jacobsoni, Tor tambra, Betta imbellis, Betta taeniata and Monopterus albus. Among the many introduced species are Anabas testudineus, Oreochromis mossambicus, Oreochromis niloticus, Ctenopharyngodon idella, Cyprinus carpio, Osphronemus goramy, Trichogaster pectoralis, Trichopodus trichopterus, Poecilia reticulata and Xiphophorus hellerii.

More recent activity
Since the major eruption ~70,000 years ago, eruptions of smaller magnitude have also occurred at Toba. The small cone of Pusukbukit formed on the southwestern margin of the caldera and lava domes. The most recent eruption may have been at Tandukbenua on the northwestern caldera edge, suggested by a lack of vegetation that could be due to an eruption within the last few hundred years.

Some parts of the caldera have shown uplift due to partial refilling of the magma chamber, for example, pushing Samosir Island and the Uluan Peninsula above the surface of the lake. The lake sediments on Samosir Island show that it has risen by at least 450 m (1,476 ft) since the cataclysmic eruption. Such uplifts are common in very large calderas, apparently due to the upward pressure of below-ground magma. Toba is probably the largest resurgent caldera on Earth. Large earthquakes have recently occurred in the vicinity of the volcano, notably in 1987 along the southern shore of the lake at a depth of 11 km (6.8 mi). Such earthquakes have also been recorded in 1892, 1916, and 1920–1922.

Lake Toba lies near the Great Sumatran fault, which runs along the centre of Sumatra in the Sumatra Fracture Zone. The volcanoes of Sumatra and Java are part of the Sunda Arc, a result of the northeasterly movement of the Indo-Australian Plate, which is sliding under the eastward-moving Eurasian Plate. The subduction zone in this area is very active: the seabed near the west coast of Sumatra has had several major earthquakes since 1995, including the 9.1 2004 Indian Ocean earthquake and the 8.7 2005 Sumatra earthquake, the epicenters of which were around 300 km (190 mi) from Toba.