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- The Boring Lava Field (also known as the Boring Volcanic Field) is a Plio-Pleistocene volcanic field with cinder cones, small shield volcanoes, and lava flows in the northern Willamette Valley of the U.S. state of Oregon and adjacent southwest Washington state. The field got its name from the town of Boring, Oregon, located 12 miles (19 km) southeast of downtown Portland. Boring lies southeast of the most dense cluster of lava vents. The zone became volcanically active about 2.7 million years ago, with long periods of eruptive activity interspersed with quiescence. Its last eruptions took place about 57,000 years ago at the Beacon Rock cinder cone volcano; the individual volcanic vents of the field are considered extinct, but the field itself is not. The volcanic field covers an area of about 1,500 square miles (3,900 km2), and it has a total volume of 2.4 cubic miles (10 km3). This region sustains diverse flora and fauna within its habitat areas, which are subject to Portland's moderate climate with variable temperatures and mild precipitation. The highest elevation of the field is at Larch Mountain, which reaches a height of 4,055 feet (1,236 m). The Portland metropolitan area, including suburbs, is one of the few places in the continental United States to have extinct volcanoes within a city's limits, and the Boring Lava Field plays an important role in local affairs, including the development of the Robertson Tunnel, recreation, and nature parks. Because of the field's proximity to densely populated areas, eruptive activity would be a threat to human life and property, but the probability for future eruptions affecting the Portland–Vancouver metropolitan area is very low. Boring Lava may also influence future earthquakes in the area, as intrusive rock from its historic eruptions may affect ground movement. (en)
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| rdfs:comment
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- The Boring Lava Field (also known as the Boring Volcanic Field) is a Plio-Pleistocene volcanic field with cinder cones, small shield volcanoes, and lava flows in the northern Willamette Valley of the U.S. state of Oregon and adjacent southwest Washington state. The field got its name from the town of Boring, Oregon, located 12 miles (19 km) southeast of downtown Portland. Boring lies southeast of the most dense cluster of lava vents. The zone became volcanically active about 2.7 million years ago, with long periods of eruptive activity interspersed with quiescence. Its last eruptions took place about 57,000 years ago at the Beacon Rock cinder cone volcano; the individual volcanic vents of the field are considered extinct, but the field itself is not. (en)
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