Mount Pinatubo is an active stratovolcano in the Zambales Mountains, located on the tripoint boundary of the Philippine provinces of Zambales and Pampanga, all in Central Luzon on the northern island of Luzon. Its eruptive history was unknown to most before the pre-eruption volcanic activities of 1991, just before June. Pinatubo was eroded and obscured from view, it was covered with dense forests. Pinatubo is most notorious for its VEI-6 eruption on June 15, 1991, the second-largest terrestrial eruption of the 20th century after the 1912 eruption of Novarupta in Alaska. Complicating the eruption was the arrival of Typhoon Yunya, bringing a lethal mix of ash and rain to towns and cities surrounding the volcano. Predictions at the onset of the climactic eruption led to the evacuation of tens of thousands of people from the surrounding areas, saving many lives. Surrounding areas were damaged by pyroclastic surges, pyroclastic falls, subsequently, by the flooding lahars caused by rainwater re-mobilizing earlier volcanic deposits.
This caused extensive destruction to infrastructure and changed river systems for years after the eruption. Minor dome-forming eruptions inside the caldera continued from 1992 to 1993; the effects of the 1991 eruption were felt worldwide. It ejected 10,000,000,000 tonnes or 10 km3 of magma, 20,000,000 tonnes of SO2, bringing vast quantities of minerals and toxic metals to the surface environment, it injected more particulate into the stratosphere than any eruption since Krakatoa in 1883. Over the following months, the aerosols formed a global layer of sulfuric acid haze. Global temperatures dropped by about 0.5 °C in the years 1991–93, ozone depletion temporarily saw a substantial increase. The volcano is 87 km northwest of Manila, the capital of the Philippines. Near Mount Pinatubo, the United States maintained two large military bases in the region; the U. S. Naval Base Subic Bay was 37 km south of Pinatubo, the extent of Clark Air Base was just 14 km east of the volcano's summit; the volcano is near to about 6 million people.
Mount Pinatubo's summit before the 1991 eruption was 1,745 m above sea level, only about 600 m above nearby plains, only about 200 m higher than surrounding peaks, which obscured it from view. It is part of a chain of volcanoes which lie along the western side of the island of Luzon called the Zambales Mountains. Pinatubo belongs to the Cabusilan sub-range of the Zambales Mountains, which consists of Mt. Cuadrado, Mt. Negron, Mt. Mataba and Mt. Pinatubo, they are subduction volcanoes, formed by the Eurasian Plate sliding under the Philippine Mobile Belt along the Manila Trench to the west. Mount Pinatubo and the other volcanoes on this volcanic belt arise due to magmatic occlusion from this subduction plate boundary. Pinatubo is flanked on the west by the Zambales Ophiolite Complex, an easterly-dipping section of Eocene oceanic crust uplifted during the late Oligocene; the Tarlac Formation north and southeast of Pinatubo consists of marine and volcanoclastic sediments formed in the late Miocene and Pliocene.
The most recent study of Mount Pinatubo before the activities of 1991 was the overall geological study in 1983 and 1984 made by F. G. Delfin for the Philippine National Oil Company as part of the surface investigations of the area before exploratory drilling and well testing for geothermal energy sources in 1988 to 1990, he recognized two life histories of the mountain, which he classified as "ancestral" and "modern" Pinatubo. Activity of Ancestral Pinatubo seems to have begun about 1.1 million years ago and ended tens of thousands of years or more before the birth of "modern" Pinatubo. Much of the rugged land around the present volcano consists of remnants of "ancestral" Pinatubo, it was an andesite and dacite stratovolcano whose eruptive activity was much less explosive than modern Pinatubo. Its center was where the current volcano is; the projected height of the mountain is up to 2,300 m, or 1.43 miles above sea level if it were a lone peak, based on a profile fitting to the remaining lower slopes, or lower if it had more than one peak.
The old volcano is exposed in the walls of an old 3.5 km × 4.5 km wide caldera, referred to as Tayawan Caldera by Delfin. Some of the nearby peaks are the remnants of ancestral Pinatubo, left behind when the softer parts of the old mountain slopes were eroded by weathering. Ancestral Pinatubo is a somma volcano with modern Pinatubo as the new cone. Mount Dorst, to the east, is part of the dip slope of the ancestral Pinatubo. Several mountains near modern Pinatubo are old satellite vents of ancestral Pinatubo, forming volcanic plugs and lava domes; these satellite vents were active around the same time as the ancestral volcano and include the domes of Mount Negron, Mount Cuadrado, Mount Mataba and the Bituin and Tapungho plugs. C. 33,000 BC: After a long period of dormancy, Modern Pinatubo was born in Ancestral Pinatubo's cataclysmic and most explosive eruptions, estimated to be five times larger than the June 1991 eruption. It deposited all around the volcano up to 25 km3 of pyroclastic surge material up to 100 metres thick.
The total volume of volcanic material ejected during the eruptions is unknown. The removal of so much material from the underlying magma chamber resulted in the Tayawan caldera; the violent eruptive period started by
As minor planet discoveries are confirmed, they are given a permanent number by the IAU's Minor Planet Center, the discoverers can submit names for them, following the IAU's naming conventions. The list below concerns those minor planets in the specified number-range that have received names, explains the meanings of those names. Official naming citations of newly named small Solar System bodies are published in MPC's Minor Planet Circulars several times a year. Recent citations can be found on the JPL Small-Body Database; until his death in 2016, German astronomer Lutz D. Schmadel compiled these citations into the Dictionary of Minor Planet Names and updated the collection. Based on Paul Herget's The Names of the Minor Planets, Schmadel researched the unclear origin of numerous asteroids, most of, named prior to World War II; this article incorporates public domain material from the United States Government document: "SBDB". New namings may only be added after official publication as the preannouncement of names is condemned by the Committee on Small Body Nomenclature.
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The Weißer Stein is located in the forest of Mürringen, a hamlet of the Büllingen municipality in the Belgian East Cantons. It is the second highest point of Belgium, it lies on the border with the German state of North Rhine-Westphalia. German measurements indicated an altitude of 689 m at the nearby located measuring point, a small higher area surrounded by the 690 meter altitude line. In 2007 the University of Liège found a height of 692 m; the altitude meter of Google Earth caused some doubt about Signal de Botrange as Belgium's highest point because its vertical reference EGM96 deviates a couple of meters from the German Normalnull and the Belgian TAW, thereby suggesting an altitude of 701 m for the Weißer Stein. An accurate control by the Belgian National Geographic Institute in 2010 showed the Weißer Stein to be at maximum 693.3 m TAW, with which it differs by less than 1 m from Signal de Botrange