Whangaehu River | |
---|---|
Etymology | Maori meaning "muddy / murky harbour" |
Native name | Whangaehu (Māori) |
Location | |
Country | New Zealand |
Region | Manawatū-Whanganui |
Physical characteristics | |
Source | Crater lake |
• location | Mount Ruapehu |
• coordinates | 39°17′2″S175°33′50″E / 39.28389°S 175.56389°E |
• elevation | 2,550 metres (8,370 ft) |
Mouth | Tasman Sea |
• coordinates | 40°2′28″S175°6′0″E / 40.04111°S 175.10000°E |
• elevation | Sea level |
Length | 161 kilometres (100 mi) |
Basin features | |
Tributaries | |
• right | Wahianoa River, Mangawhero River |
The Whangaehu River is a large river in central North Island of New Zealand. Its headwaters are the crater lake of Mount Ruapehu on the central plateau, and it flows into the Tasman Sea eight kilometres southeast of Whanganui. Due to the high acidity of the water coming from the crater lake, water is not diverted from the headwaters for the Tongariro Power Scheme. Instead, it bypasses the Waihianoa Aqueduct via a ford.
The river flows for 161 kilometres (100 mi) southward to the South Taranaki Bight near the settlement of Whangaehu.
The sudden collapse of part of the Ruapehu crater wall on 24 December 1953 led to New Zealand's worst railway accident, the Tangiwai disaster. A lahar – a sudden surge of mud-laden water – swept down the river, significantly weakening the structure of a railway bridge at the small settlement of Tangiwai. The overnight express train between Wellington and Auckland passed over the bridge minutes later, causing it to collapse into the turbulent waters. Of the 285 people on the train, 151 were killed.
The river is often poisoned with toxic chemicals from the volcanic activity in and around Mount Ruapehu. The upper part of the river begins as the meltwater from a small glacier. When hot water from the lake spills, it quickly melts the ice and snow in the glacier forming a cave-like tunnel. [3]
Mount Ruapehu is an active stratovolcano at the southern end of the Taupō Volcanic Zone and North Island volcanic plateau in New Zealand. It is 23 km (14 mi) northeast of Ohakune and 23 km (14 mi) southwest of the southern shore of Lake Taupō, within the Tongariro National Park. The North Island's major ski resorts and only glaciers are on its slopes.
The Ring of Fire is a tectonic belt of volcanoes and earthquakes.
A lahar is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley.
Nevado del Ruiz, also known as La Mesa de Herveo is a volcano on the border of the departments of Caldas and Tolima in Colombia, being the highest point of both. It is located about 130 km (81 mi) west of the capital city Bogotá. It is a stratovolcano composed of many layers of lava alternating with hardened volcanic ash and other pyroclastic rocks. Volcanic activity at Nevado del Ruiz began about two million years ago, during the Early Pleistocene or Late Pliocene, with three major eruptive periods. The current volcanic cone formed during the present eruptive period, which began 150,000 years ago.
The Tangiwai disaster was a deadly railway accident that occurred at 10:21 p.m. on 24 December 1953, when a railway bridge over the Whangaehu River collapsed beneath an express passenger train at Tangiwai, North Island, New Zealand. The locomotive and the first six carriages derailed into the river, killing 151 people. The subsequent board of inquiry found that the accident was caused by the failure of the tephra dam holding back nearby Mount Ruapehu's crater lake, creating a rapid mudflow (lahar) in the Whangaehu River which destroyed one of the bridge piers at Tangiwai only minutes before the train reached the bridge. The volcano at Mount Ruapehu was not erupting at the time. The disaster remains New Zealand's worst rail accident.
Mount Tongariro is a compound volcano in the Taupō Volcanic Zone of the North Island of New Zealand. It is located 20 km (12 mi) to the southwest of Lake Taupō, and is the northernmost of the three active volcanoes that dominate the landscape of the central North Island.
The North Island Volcanic Plateau is a volcanic plateau covering much of central North Island of New Zealand with volcanoes, lava plateaus, and crater lakes. It contains the Taupō caldera complex, Ōkataina caldera complex and Tongariro Volcanic Centre resulting in it being currently the most frequently active and productive area of silicic volcanism on Earth. New Zealand is part of the Pacific Ring of Fire.
The Armero tragedy occurred following the eruption of the Nevado del Ruiz stratovolcano in Tolima, Colombia, on November 13, 1985. The volcano's eruption after 69 years of dormancy caught nearby towns unprepared, even though volcanological organizations had warned the government to evacuate the area after they detected volcanic activity two months earlier.
Villarrica is one of Chile's most active volcanoes, rising above the lake and town of the same name, 750 km (470 mi) south of Santiago. It is also known as Rucapillán, a Mapuche word meaning "great spirit's house" or " the demon's house". It is the westernmost of three large stratovolcanoes that trend northwest to southeast obliquely perpendicular to the Andean chain along the Mocha-Villarrica Fault Zone, and along with Quetrupillán and the Chilean portion of Lanín, are protected within Villarrica National Park. Guided ascents are popular during summer months.
Broken Top is a glacially eroded complex stratovolcano. It lies in the Cascade Volcanic Arc, part of the extensive Cascade Range in the U.S. state of Oregon. Located southeast of the Three Sisters peaks, the volcano, residing within the Three Sisters Wilderness, is 20 miles (32 km) west of Bend, Oregon in Deschutes County. Eruptive activity stopped roughly 100,000 years ago, and erosion by glaciers has since reduced the volcano's cone to where its contents are exposed. There are two named glaciers on the peak, Bend and Crook Glacier.
The Valigonda rail disaster occurred on 29 October 2005 near the town of Valigonda, south of Hyderabad in the Indian state of Telangana. A flash flood swept away a small rail bridge, and a "Delta Fast Passenger" train traveling on it derailed at the broken section of the line, killing at least 114 people and injuring over 200.
The Eastern Ruapehu Lahar Alarm and Warning System (ERLAWS) is a lahar warning system that was installed on Mount Ruapehu, New Zealand following volcanic eruptions in 1995–1996. The system successfully detected and warned of an imminent lahar in March 2007. The system is being expanded to detect the wider range of lahar threats now expected on Ruapehu.
The Mount Meager massif is a group of volcanic peaks in the Pacific Ranges of the Coast Mountains in southwestern British Columbia, Canada. Part of the Cascade Volcanic Arc of western North America, it is located 150 km (93 mi) north of Vancouver at the northern end of the Pemberton Valley and reaches a maximum elevation of 2,680 m (8,790 ft). The massif is capped by several eroded volcanic edifices, including lava domes, volcanic plugs and overlapping piles of lava flows; these form at least six major summits including Mount Meager which is the second highest of the massif.
Subglacial eruptions, those of ice-covered volcanoes, result in the interaction of magma with ice and snow, leading to meltwater formation, jökulhlaups, and lahars. Flooding associated with meltwater is a significant hazard in some volcanic areas, including Iceland, Alaska, and parts of the Andes. Jökulhlaups have been identified as the most frequently occurring volcanic hazard in Iceland, with major events where peak discharges of meltwater can reach 10,000 – 100,000 m3/s occurring when there are large eruptions beneath glaciers. It is important to explore volcano-ice interactions to improve the effectiveness of monitoring these events and to undertake hazard assessments. This is particularly relevant given that subglacial eruptions have demonstrated their ability to cause widespread impact, with the ash cloud associated with Iceland's Eyjafjallajökull eruption in 2010 resulting in significant impacts to aviation across Europe.
Mangamahu is a hill-country farming and forestry community in the middle reaches of the Whangaehu River valley, in the Whanganui District and Rangitikei District of Manawatū-Whanganui, New Zealand. It is centred on the village of Mangamahu, which is situated on river flats where the Mangamahu stream flows into the Whangaehu river. Mangamahu has a primary school which has been open since 1894 and a War Memorial Hall built in 1952.
The volcanism of New Zealand has been responsible for many of the country's geographical features, especially in the North Island and the country's outlying islands.
State Highway 49 (SH 49) is a New Zealand state highway, linking SH 4 and SH 1, via the tourist town of Ohakune. It forms the southern part of the ring road surrounding Tongariro National Park and provides access to the southern side of Mount Ruapehu and the Turoa skifield. It roughly follows the North Island Main Trunk railway.
Lake Pinatubo is the summit crater lake of Mount Pinatubo formed after its climactic eruption on June 15, 1991. The lake is located in the Zambales Mountains, in Botolan, Zambales, near the boundaries of Pampanga and Tarlac provinces in the Philippines. It is about 90 km (56 mi) northwest of the capital city of Manila. While one paper by researchers from Japan suggested a depth of 600 m (2,000 ft), more detailed research suggests that 95–115 m (312–377 ft) is more accurate.
A volcanic crater lake is a lake in a crater that was formed by explosive activity or a collapse during a volcanic eruption.
Whangaehu is a settlement in the Rangitikei District and Manawatū-Whanganui region of New Zealand's North Island.