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109-607: Mount Erebus ( / ˈ ɛr ɪ b ə s / ) is the southernmost active volcano on Earth, located on Ross Island in the Ross Dependency in Antarctica . With a summit elevation of 3,792 metres (12,441 ft), it is the second most prominent mountain in Antarctica (after Mount Vinson ) and the second-highest volcano in Antarctica (after the dormant Mount Sidley ). It is the highest point on Ross Island, which

218-458: A feedback circuit. The amount of force necessary to achieve this is then recorded. In most designs the electronics holds a mass motionless relative to the frame. This device is called a "force balance accelerometer". It measures acceleration instead of velocity of ground movement. Basically, the distance between the mass and some part of the frame is measured very precisely, by a linear variable differential transformer . Some instruments use

327-408: A geo-sismometro , possibly the first use of a similar word to seismometer . Naturalist Nicolo Zupo devised an instrument to detect electrical disturbances and earthquakes at the same time (1784). The first moderately successful device for detecting the time of an earthquake was devised by Ascanio Filomarino in 1796, who improved upon Salsano's pendulum instrument, using a pencil to mark, and using

436-431: A linear variable differential capacitor . That measurement is then amplified by electronic amplifiers attached to parts of an electronic negative feedback loop . One of the amplified currents from the negative feedback loop drives a coil very like a loudspeaker . The result is that the mass stays nearly motionless. Most instruments measure directly the ground motion using the distance sensor. The voltage generated in

545-467: A US Navy ship. Along with other Navy icebreakers, Glacier was transferred to the US Coast Guard fleet, June 1966, from which she operated until decommissioned, June 1987. 77°29′S 167°06′E  /  77.483°S 167.100°E  / -77.483; 167.100 . A glacier on the west side of Fang Ridge, separating the old and new craters of Mount Erebus. Charted by Frank Debenham of

654-402: A coil attached to the mass which voltage moves through the magnetic field of a magnet attached to the frame. This design is often used in a geophone , which is used in exploration for oil and gas. Seismic observatories usually have instruments measuring three axes: north-south (y-axis), east–west (x-axis), and vertical (z-axis). If only one axis is measured, it is usually the vertical because it

763-554: A copy of which can be found at the University Library in Bologna, and a further mercury seismoscope was constructed by Niccolò Cacciatore in 1818. James Lind also built a seismological tool of unknown design or efficacy (known as an earthquake machine) in the late 1790s. Pendulum devices were developing at the same time. Neapolitan naturalist Nicola Cirillo set up a network of pendulum earthquake detectors following

872-406: A digital seismograph can be simply input to a computer. It presents the data in a standard digital format (often "SE2" over Ethernet ). The modern broadband seismograph can record a very broad range of frequencies . It consists of a small "proof mass", confined by electrical forces, driven by sophisticated electronics . As the earth moves, the electronics attempt to hold the mass steady through

981-527: A given quake. Luigi Palmieri , influenced by Mallet's 1848 paper, invented a seismometer in 1856 that could record the time of an earthquake. This device used metallic pendulums which closed an electric circuit with vibration, which then powered an electromagnet to stop a clock. Palmieri seismometers were widely distributed and used for a long time. By 1872, a committee in the United Kingdom led by James Bryce expressed their dissatisfaction with

1090-433: A hair attached to the mechanism to inhibit the motion of a clock's balance wheel. This meant that the clock would only start once an earthquake took place, allowing determination of the time of incidence. After an earthquake taking place on October 4, 1834, Luigi Pagani observed that the mercury seismoscope held at Bologna University had completely spilled over, and did not provide useful information. He therefore devised

1199-670: A line from Cape Royds to the crater of Mount Erebus. The cone itself is about 100 metres (330 ft) high high and is surrounded by a deep moat or ditch, caused by the sweeping action of strong winds. It was named by F. Debenham on the second ascent of Mount Erebus for F.J. Hooper, a steward of the British Antarctic Expedition, 1910-13. Hooper was one of the party making the second ascent. 77°32′26″S 166°51′02″E  /  77.540504°S 166.850438°E  / -77.540504; 166.850438 Two rock summits at about 1,500 metres (4,900 ft) high on

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1308-414: A low-budget way to get some of the performance of the closed-loop wide-band geologic seismographs. Strain-beam accelerometers constructed as integrated circuits are too insensitive for geologic seismographs (2002), but are widely used in geophones. Some other sensitive designs measure the current generated by the flow of a non-corrosive ionic fluid through an electret sponge or a conductive fluid through

1417-544: A member of the expedition. 77°27′14″S 166°48′57″E  /  77.454003°S 166.815833°E  / -77.454003; 166.815833 . Two rock summits rising to over 1,400 metres (4,600 ft) high on the northwest slope of Mount Erebus . The feature is 1.2 nautical miles (2.2 km; 1.4 mi) west-northwest of Abbott Peak. At the suggestion of P.R. Kyle, named by Advisory Committee on Antarctic Names (US-ACAN) (2000) after Sarah Krall who worked over 10 years in providing support to science in Antarctica. She

1526-557: A number of rock formations. Features around the summit of the mountain include: 77°30′12″S 167°07′01″E  /  77.503455°S 167.116913°E  / -77.503455; 167.116913 . Prominent cliffs at about 3,525 metres (11,565 ft) high on the north rim of the summit caldera of Mount Erebus. The name derives from a nearby United States Coast Guard (USCG) HH-52A helicopter (CG 1404) which lost power and crashed while enroute from McMurdo Station to Cape Bird, Jan. 9, 1971. The four crew and passengers were not injured, but

1635-552: A portable device that used lead shot to detect the direction of an earthquake, where the lead fell into four bins arranged in a circle, to determine the quadrant of earthquake incidence. He completed the instrument in 1841. In response to a series of earthquakes near Comrie in Scotland in 1839, a committee was formed in the United Kingdom in order to produce better detection devices for earthquakes. The outcome of this

1744-487: A seismometer was deployed on the planet Mars by the InSight lander, the first time a seismometer was placed onto the surface of another planet. In Ancient Egypt , Amenhotep, son of Hapu invented a precursor of seismometer, a vertical wooden poles connected with wooden gutters on the central axis functioned to fill water into a vessel until full to detect earthquakes. In AD 132 , Zhang Heng of China's Han dynasty

1853-508: A sense coil on the mass by the magnet directly measures the instantaneous velocity of the ground. The current to the drive coil provides a sensitive, accurate measurement of the force between the mass and frame, thus measuring directly the ground's acceleration (using f=ma where f=force, m=mass, a=acceleration). One of the continuing problems with sensitive vertical seismographs is the buoyancy of their masses. The uneven changes in pressure caused by wind blowing on an open window can easily change

1962-415: A talus of large anorthoclase feldspar crystals. 77°31′16″S 167°08′49″E  /  77.521068°S 167.146857°E  / -77.521068; 167.146857 A prominent outcropping of jumbled rocks, 3,633 metres (11,919 ft) high, formed as a lava flow on the northwest upper slope of the active cone of Mount Erebus. The feature is near a camp site used mainly in the 1970s by teams working at

2071-499: A vacuum to reduce disturbances from air currents. Zollner described torsionally suspended horizontal pendulums as early as 1869, but developed them for gravimetry rather than seismometry. Early seismometers had an arrangement of levers on jeweled bearings, to scratch smoked glass or paper. Later, mirrors reflected a light beam to a direct-recording plate or roll of photographic paper. Briefly, some designs returned to mechanical movements to save money. In mid-twentieth-century systems,

2180-574: Is a digital strong-motion seismometer, or accelerograph . The data from such an instrument is essential to understand how an earthquake affects man-made structures, through earthquake engineering . The recordings of such instruments are crucial for the assessment of seismic hazard , through engineering seismology . A strong-motion seismometer measures acceleration. This can be mathematically integrated later to give velocity and position. Strong-motion seismometers are not as sensitive to ground motions as teleseismic instruments but they stay on scale during

2289-466: Is also home to three inactive volcanoes: Mount Terror , Mount Bird , and Mount Terra Nova . It makes Ross Island the sixth-highest island on Earth. The mountain was named by Captain James Clark Ross in 1841 for his ship, HMS Erebus . The volcano has been active for around 1.3 million years and has a long-lived lava lake in its inner summit crater that has been present since at least

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2398-453: Is called seismometry , a branch of seismology . The concept of measuring the "shaking" of something means that the word "seismograph" might be used in a more general sense. For example, a monitoring station that tracks changes in electromagnetic noise affecting amateur radio waves presents an rf seismograph . And helioseismology studies the "quakes" on the Sun . The first seismometer

2507-451: Is less noisy and gives better records of some seismic waves. The foundation of a seismic station is critical. A professional station is sometimes mounted on bedrock . The best mountings may be in deep boreholes, which avoid thermal effects, ground noise and tilting from weather and tides. Other instruments are often mounted in insulated enclosures on small buried piers of unreinforced concrete. Reinforcing rods and aggregates would distort

2616-608: Is notable for its numerous ice fumaroles – ice towers that form around gases that escape from vents in the surface. The ice caves associated with the fumaroles are dark, in polar alpine environments starved in organics and with oxygenated hydrothermal circulation in highly reducing host rock. The life is sparse, mainly bacteria and fungi. This makes it of special interest for studying oligotrophs – organisms that can survive on minimal amounts of resources. The caves on Erebus are of special interest for astrobiology, as most surface caves are influenced by human activities, or by organics from

2725-443: Is placed under the arm, and a small sheet of metal mounted on the underside of the arm drags in the oil to damp oscillations. The level of oil, position on the arm, and angle and size of sheet is adjusted until the damping is "critical", that is, almost having oscillation. The hinge is very low friction, often torsion wires, so the only friction is the internal friction of the wire. Small seismographs with low proof masses are placed in

2834-602: Is said to have invented the first seismoscope (by the definition above), which was called Houfeng Didong Yi (translated as, "instrument for measuring the seasonal winds and the movements of the Earth"). The description we have, from the History of the Later Han Dynasty , says that it was a large bronze vessel, about 2 meters in diameter; at eight points around the top were dragon's heads holding bronze balls. When there

2943-417: Is the site of a slump which has occurred off the crater rim. It is also a former camp site used by summit parties. A small hut is located on the upper part of the slope. 77°31′37″S 167°08′45″E  /  77.52682°S 167.145742°E  / -77.52682; 167.145742 . A gully at about 3,675 metres (12,057 ft) high on the northwest side of the summit crater of Mount Erebus. The feature

3052-413: Is the world's only presently erupting phonolite volcano. Lava flows of more viscous phonotephrite and trachyte erupted after the basanite. The upper slopes of Mount Erebus are dominated by steeply dipping (about 30°) tephritic phonolite lava flows with large-scale flow levees. A conspicuous break in slope around 3,200 m ASL calls attention to a summit plateau representing a caldera . The summit caldera

3161-520: Is thought to refer to a pendulum, though it is not known exactly how this was linked to a mechanism that would open only one dragon's mouth. The first earthquake recorded by this seismoscope was supposedly "somewhere in the east". Days later, a rider from the east reported this earthquake. By the 13th century, seismographic devices existed in the Maragheh observatory (founded 1259) in Persia, though it

3270-439: Is unclear whether these were constructed independently or based on the first seismoscope. French physicist and priest Jean de Hautefeuille described a seismoscope in 1703, which used a bowl filled with mercury which would spill into one of eight receivers equally spaced around the bowl, though there is no evidence that he actually constructed the device. A mercury seismoscope was constructed in 1784 or 1785 by Atanasio Cavalli ,

3379-456: The Greek σεισμός, seismós , a shaking or quake, from the verb σείω, seíō , to shake; and μέτρον, métron , to measure, and was coined by David Milne-Home in 1841, to describe an instrument designed by Scottish physicist James David Forbes . Seismograph is another Greek term from seismós and γράφω, gráphō , to draw. It is often used to mean seismometer , though it is more applicable to

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3488-672: The Marsden Fund granted nearly NZ$ 1 million to the University of Waikato and the University of Canterbury to study the micro-organisms in the geothermal fumaroles. Mount Erebus was discovered on 27 January 1841 (and observed to be in eruption), by polar explorer Sir James Clark Ross on his Antarctic expedition , who named it and its companion, Mount Terror , after his ships, HMS Erebus and HMS Terror (which were later used and lost by Sir John Franklin on his disastrous Arctic expedition ). Present with Ross on HMS Erebus

3597-562: The Smithsonian Institution 's Global Volcanism Program recognizes 560 volcanoes with confirmed historical eruptions. Countries with the most Holocene volcanoes, according to the Smithsonian Institution's Global Volcanism Program (as of 2023 ): Countries with the most volcanoes active since 1960 (as of 2023 ): As of 2013, the following are considered Earth's most active volcanoes: As of 2010 ,

3706-492: The South Pole , accomplished a solo ascent in about 17 hours completely unsupported, by snow mobile and on foot. In 1992, the inside of the volcano was explored by Dante I , an eight legged tethered robotic explorer. Dante was designed to acquire gas samples from the magma lake inside the inner crater of Mount Erebus to understand the chemistry better through the use of the on-board gas chromatograph , as well as measuring

3815-445: The inertia to stay still within the frame . The result is that the stylus scratched a pattern corresponding with the Earth's movement. This type of strong-motion seismometer recorded upon a smoked glass (glass with carbon soot ). While not sensitive enough to detect distant earthquakes, this instrument could indicate the direction of the pressure waves and thus help find the epicenter of a local quake. Such instruments were useful in

3924-423: The 1731 Puglia Earthquake, where the amplitude was detected using a protractor to measure the swinging motion. Benedictine monk Andrea Bina further developed this concept in 1751, having the pendulum create trace marks in sand under the mechanism, providing both magnitude and direction of motion. Neapolitan clockmaker Domenico Salsano produced a similar pendulum which recorded using a paintbrush in 1783, labelling it

4033-645: The BrAE, 1910–13, and named by him in association with Fang Ridge. Active volcano An active volcano is a volcano that has erupted during the Holocene (the current geologic epoch that began approximately 11,700 years ago), is currently erupting, or has the potential to erupt in the future. A volcano that is not currently erupting but could erupt in the future is known as a dormant volcano . Volcanoes that will not erupt again are known as extinct volcanoes . There are 1,350 potentially active volcanoes around

4142-415: The Earth, is like a weight hanging from a spring, both suspended from a frame that moves along with any motion detected. The relative motion between the weight (called the mass) and the frame provides a measurement of the vertical ground motion . A rotating drum is attached to the frame and a pen is attached to the weight, thus recording any ground motion in a seismogram . Any movement from the ground moves

4251-471: The Erebus summit. So named by Advisory Committee on Antarctic Names (US-ACAN) in the millennium year 2000. 77°29′17″S 167°28′39″E  /  77.488132°S 167.477419°E  / -77.488132; 167.477419 . A peak rising to about 1,600 metres (5,200 ft) high on the northeast slope of Mount Erebus, 3.6 nautical miles (6.7 km; 4.1 mi) east of the summit of Fang Ridge. Named by

4360-492: The New Mexico Institute of Mining and Technology, known as New Mexico Tech. From 1981, many Tech students under the direction of Philip R. Kyle, have undertaken graduate research projects (thesis and dissertation) on Mount Erebus. 77°34′S 166°58′E  /  77.567°S 166.967°E  / -77.567; 166.967 . Three aligned cones at an elevation of about 1,800 metres (5,900 ft) high on

4469-667: The New Zealand Geographic Board (NZGB) (2000) after Father Coleman, a New Zealand chaplain, who traveled to Antarctica many times with the United States Antarctic Program. 77°26′51″S 167°33′41″E  /  77.447407°S 167.561469°E  / -77.447407; 167.561469 . A peak about 890 metres (2,920 ft) high, located 1.5 nautical miles (2.8 km; 1.7 mi) west of Terra Nova Glacier and 2 nautical miles (3.7 km; 2.3 mi) south of Lewis Bay on

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4578-790: The Pacific Northwest of the United States and Canada, it reaches back less than 300 years, and in Hawaii and New Zealand it is only around 200 years. The incomplete Catalogue of the Active Volcanoes of the World , published in parts between 1951 and 1975 by the International Association of Volcanology , uses this definition, by which there are more than 500 active volcanoes. As of March 2021 ,

4687-486: The analysis of the 1906 San Francisco earthquake . Further analysis was performed in the 1980s, using these early recordings, enabling a more precise determination of the initial fault break location in Marin county and its subsequent progression, mostly to the south. Later, professional suites of instruments for the worldwide standard seismographic network had one set of instruments tuned to oscillate at fifteen seconds, and

4796-418: The bulk of exposed lava flow on the volcano. The oldest eruptive products consist of relatively undifferentiated and nonviscous basanite lavas that form the low broad platform shield of Erebus. Slightly younger basanite and phonotephrite lavas crop out on Fang Ridge – an eroded remnant of an early Erebus volcano – and at other isolated locations on the flanks of Erebus. Erebus

4905-623: The camp sites they used have been recognised for their historic significance: They have been designated historic sites or monuments following a proposal by the United Kingdom, New Zealand, and the United States to the Antarctic Treaty Consultative Meeting . Mount Erebus' summit crater rim was first achieved by members of Sir Ernest Shackleton 's party; Professor Edgeworth David , Sir Douglas Mawson , Dr Alister Mackay , Alex Lagasse, Jameson Adams , Dr Eric Marshall and Phillip Brocklehurst (who did not reach

5014-406: The caves has 80 to 100% humidity, and up to 3% carbon dioxide (CO 2 ), and some carbon monoxide (CO) and hydrogen (H 2 ), but almost no methane (CH 4 ) or hydrogen sulfide (H 2 S). Many of them are completely dark, so cannot support photosynthesis. Organics can only come from the atmosphere, or from ice algae that grow on the surface in summer, which may eventually find their way into

5123-434: The caves through burial and melting. As a result, most micro-organisms there are chemolithoautotrophic i.e. microbes that get all of their energy from chemical reactions with the rocks, and that do not depend on any other lifeforms to survive. The organisms survive using CO 2 fixation and some may use CO oxidization for the metabolism. The main types of microbe found there are Chloroflexota and Acidobacteriota . In 2019,

5232-436: The collision ruled out the "flying in a cloud" theory, showing perfectly clear visibility well beneath the cloud base, with landmarks visible 13 miles (21 km) to the left and 10 miles (16 km) to the right of the aircraft. The mountain directly ahead was lit by sunlight shining from directly behind the aircraft through the cloud deck above, resulting in a lack of shadows that made Mount Erebus effectively invisible against

5341-546: The crater within the floor of Main Crater, at the summit of Mount Erebus. Inner Crater contains an active anorthoclase-phonolite lava lake. The name derives from the fact that the crater is within the Main Crater of Mount Erebus. 77°31′47″S 167°08′36″E  /  77.529609°S 167.14334°E  / -77.529609; 167.14334 A nearly circular crater, about 3,700 metres (12,100 ft) high, situated at

5450-561: The current available seismometers, still using the large 1842 Forbes device located in Comrie Parish Church, and requested a seismometer which was compact, easy to install and easy to read. In 1875 they settled on a large example of the Mallet device, consisting of an array of cylindrical pins of various sizes installed at right angles to each other on a sand bed, where larger earthquakes would knock down larger pins. This device

5559-402: The density of the air in a room enough to cause a vertical seismograph to show spurious signals. Therefore, most professional seismographs are sealed in rigid gas-tight enclosures. For example, this is why a common Streckeisen model has a thick glass base that must be glued to its pier without bubbles in the glue. It might seem logical to make the heavy magnet serve as a mass, but that subjects

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5668-455: The device to begin recording, and then a recording surface would produce a graphical illustration of the tremors automatically (a seismogram). However, the instrument was not sensitive enough, and the first seismogram produced by the instrument was in 1887, by which time John Milne had already demonstrated his design in Japan . In 1880, the first horizontal pendulum seismometer was developed by

5777-485: The early 1970s. On 28 November, 1979, Air New Zealand Flight 901 crashed on Mount Erebus, killing all 257 people on board. Mount Erebus is the world's southernmost active volcano. It is the current eruptive centre of the Erebus hotspot . The summit contains a persistent convecting phonolitic lava lake, one of five long-lasting lava lakes on Earth. Characteristic eruptive activity consists of Strombolian eruptions from

5886-425: The first horizontal pendulum was used in a seismometer, reported by Milne (though it is unclear if he was the original inventor). After these inventions, Robert Mallet published an 1848 paper where he suggested ideas for seismometer design, suggesting that such a device would need to register time, record amplitudes horizontally and vertically, and ascertain direction. His suggested design was funded, and construction

5995-414: The first modern seismometer. This produced the first effective measurement of horizontal motion. Gray would produce the first reliable method for recording vertical motion, which produced the first effective 3-axis recordings. An early special-purpose seismometer consisted of a large, stationary pendulum , with a stylus on the bottom. As the earth started to move, the heavy mass of the pendulum had

6104-608: The flanks of Mount Erebus continually reveals debris from the crash that is visible from the air. 77°31′43″S 167°09′35″E  /  77.528689°S 167.159805°E  / -77.528689; 167.159805 . The topographic feature that rises to about 3,750 metres (12,300 ft) high and forms the primary summit crater of Mount Erebus. Inner Crater, which lies within Main Crater, contains an anorthoclase-phonolite lava lake. 77°31′37″S 167°09′55″E  /  77.527048°S 167.16524°E  / -77.527048; 167.16524 . The topographic feature that embraces

6213-415: The frame by an electronic negative feedback loop . The motion of the mass relative to the frame is measured, and the feedback loop applies a magnetic or electrostatic force to keep the mass nearly motionless. The voltage needed to produce this force is the output of the seismometer, which is recorded digitally. In other systems the weight is allowed to move, and its motion produces an electrical charge in

6322-429: The frame. The mass tends not to move because of its inertia , and by measuring the movement between the frame and the mass, the motion of the ground can be determined. Early seismometers used optical levers or mechanical linkages to amplify the small motions involved, recording on soot-covered paper or photographic paper. Modern instruments use electronics. In some systems, the mass is held nearly motionless relative to

6431-455: The garden-gate described above. Vertical instruments use some kind of constant-force suspension, such as the LaCoste suspension. The LaCoste suspension uses a zero-length spring to provide a long period (high sensitivity). Some modern instruments use a "triaxial" or "Galperin" design , in which three identical motion sensors are set at the same angle to the vertical but 120 degrees apart on

6540-525: The helicopter was abandoned because of its location. 77°31′54″S 167°04′47″E  /  77.531538°S 167.079644°E  / -77.531538; 167.079644 Steep bluff at about 3,470 metres (11,380 ft) high on the southwest rim of the summit caldera of Mount Erebus. So named after a seismic station nearby. 77°31′58″S 167°06′46″E  /  77.532647°S 167.112645°E  / -77.532647; 167.112645 . A ridge at about 3,540 metres (11,610 ft) high that descends

6649-482: The highest point of Fang Ridge. Descriptively named by Frank Debenham of British Antarctic Expedition (British Antarctic Expedition), 1910-13, who made a plane table survey of the vicinity in 1912. 77°30′24″S 167°22′54″E  /  77.506569°S 167.381754°E  / -77.506569; 167.381754 . A peak rising to about 1,800 metres (5,900 ft) high on the northeast slope of Mount Erebus, 4 nautical miles (7.4 km; 4.6 mi) east-northeast of

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6758-634: The horizontal. Vertical and horizontal motions can be computed from the outputs of the three sensors. Seismometers unavoidably introduce some distortion into the signals they measure, but professionally designed systems have carefully characterized frequency transforms. Modern sensitivities come in three broad ranges: geophones , 50 to 750 V /m; local geologic seismographs, about 1,500 V/m; and teleseismographs, used for world survey, about 20,000 V/m. Instruments come in three main varieties: short period, long period and broadband. The short and long period measure velocity and are very sensitive, however they 'clip'

6867-531: The ice at McMurdo Sound in January 1956. 77°36′49″S 166°46′02″E  /  77.613497°S 166.767316°E  / -77.613497; 166.767316 . A narrow broken ridge 2 nautical miles (3.7 km; 2.3 mi) south of Williams Cliff on Ross Island. The feature rises to about 1,000 metres (3,300 ft) high and marks a declivity along the north flank of broad Turks Head Ridge, from which ice moves to Pukaru Icefalls. Named by US-ACAN (2000) after

6976-479: The ice-covered southwest slopes of Mount Erebus, situated 6 nautical miles (11 km; 6.9 mi) east of Cape Barne . This rock cliff was mapped by the British Antarctic Expedition under Scott, 1910-13, and identified simply as "Bold Cliff on maps resulting from that expedition. It was named Williams Cliff by the US-ACAN in 1964 to commemorate Richard T. Williams, who losi: his life when his tractor broke through

7085-498: The lava lake or from one of several subsidiary vents, all within the volcano's inner crater. The volcano is scientifically remarkable in that its relatively low-level and unusually persistent eruptive activity enables long-term volcanological study of a Strombolian eruptive system very close (hundreds of metres) to the active vents, a characteristic shared with only a few volcanoes on Earth, such as Stromboli in Italy. Scientific study of

7194-498: The light was reflected to a pair of differential electronic photosensors called a photomultiplier. The voltage generated in the photomultiplier was used to drive galvanometers which had a small mirror mounted on the axis. The moving reflected light beam would strike the surface of the turning drum, which was covered with photo-sensitive paper. The expense of developing photo-sensitive paper caused many seismic observatories to switch to ink or thermal-sensitive paper. After World War II,

7303-684: The longest ongoing (but not necessarily continuous) volcanic eruptive phases are: Other highly active volcanoes include: Holocene volcanoes with large populations within 5 km (3.1 mi): Michoacan-Guanajuato volcano in Mexico and Tatun Volcanic Group in Taiwan both have more than 5 million people living within 5 kilometers (3.1 mi) of the volcano. Campi Flegrei in Italy and Ilopango in El Salvador both have populations of over 2 million people living within 5 kilometers (3.1 mi) of

7412-444: The lower northeast slope of Mount Erebus. On November 28, 1979, an Air New Zealand McDonnell Douglas DC-10 aircraft on a scenic flight from Auckland crashed near this peak claiming the lives of 237 passengers from eight countries and a crew of 20. In 1987, a stainless steel memorial cross was erected west of the peak. Te Puna Roimata Peak (meaning spring of tears) was named by the New Zealand Geographic Board (NZGB) in 2000. Features of

7521-476: The next year, one being a common-pendulum seismometer and the other being the first seismometer using a damped horizontal pendulum. The innovative recording system allowed for a continuous record, the first to do so. The first seismogram was recorded on 3 November 1880 on both of Ewing's instruments. Modern seismometers would eventually descend from these designs. Milne has been referred to as the 'Father of modern seismology' and his seismograph design has been called

7630-474: The northeast slope of Mount Erebus. It is a much denuded portion of the original caldera rim left by a catastrophic eruption. So named, probably for its curved shape, by Frank Debenham of the British Antarctic Expedition, 1910-13, who made a plane table survey in 1912. 77°29′09″S 167°12′13″E  /  77.485943°S 167.203614°E  / -77.485943; 167.203614 . A distinctive toothlike peak, 3,159 metres (10,364 ft) high, which forms

7739-648: The northwest slope of Mount Erebus. The feature is 1.2 nautical miles (2.2 km; 1.4 mi) south-southwest of Abbott Peak. Named by New Zealand Geographic Board (NZGB) (2000) after Sergeant L.W. (Wally) Tarr, Royal New Zealand Air Force, aircraft mechanic with the New Zealand contingent of the Commonwealth Trans-Antarctic Expedition (CTAE), 1956-58. 77°29′S 167°12′E  /  77.483°S 167.200°E  / -77.483; 167.200 . A conspicuous ridge on

7848-417: The older instruments in which the measuring and recording of ground motion were combined, than to modern systems, in which these functions are separated. Both types provide a continuous record of ground motion; this record distinguishes them from seismoscopes , which merely indicate that motion has occurred, perhaps with some simple measure of how large it was. The technical discipline concerning such devices

7957-407: The other at ninety seconds, each set measuring in three directions. Amateurs or observatories with limited means tuned their smaller, less sensitive instruments to ten seconds. The basic damped horizontal pendulum seismometer swings like the gate of a fence. A heavy weight is mounted on the point of a long (from 10 cm to several meters) triangle, hinged at its vertical edge. As the ground moves,

8066-460: The overcast sky beyond in a classic whiteout (more accurately, "flat-light") phenomenon. Further investigation of the crash showed a navigational error in flight documentation by Air New Zealand and a cover-up that resulted in about $ 100 million in lawsuits. Air New Zealand discontinued its flyovers of Antarctica. Its final flight was on February 17, 1980. During the Antarctic summer, snow melt on

8175-442: The pier as the temperature changes. A site is always surveyed for ground noise with a temporary installation before pouring the pier and laying conduit. Originally, European seismographs were placed in a particular area after a destructive earthquake. Today, they are spread to provide appropriate coverage (in the case of weak-motion seismology ) or concentrated in high-risk regions ( strong-motion seismology ). The word derives from

8284-417: The refracted and scattered seismic waves, the scientists produced an image of the uppermost (top few km) of the volcano to understand the geometry of its "plumbing" and how the magma rises to the lava lake. These results demonstrated a complex upper-volcano conduit system with appreciable upper-volcano magma storage to the northwest of the lava lake at depths hundreds of meters below the surface. Mount Erebus

8393-400: The seismograph to errors when the Earth's magnetic field moves. This is also why seismograph's moving parts are constructed from a material that interacts minimally with magnetic fields. A seismograph is also sensitive to changes in temperature so many instruments are constructed from low expansion materials such as nonmagnetic invar . The hinges on a seismograph are usually patented, and by

8502-475: The seismometers developed by Milne, Ewing and Gray were adapted into the widely used Press-Ewing seismometer . Modern instruments use electronic sensors, amplifiers, and recording devices. Most are broadband covering a wide range of frequencies. Some seismometers can measure motions with frequencies from 500 Hz to 0.00118 Hz (1/500 = 0.002 seconds per cycle, to 1/0.00118 = 850 seconds per cycle). The mechanical suspension for horizontal instruments remains

8611-413: The signal or go off-scale for ground motion that is strong enough to be felt by people. A 24-bit analog-to-digital conversion channel is commonplace. Practical devices are linear to roughly one part per million. Delivered seismometers come with two styles of output: analog and digital. Analog seismographs require analog recording equipment, possibly including an analog-to-digital converter. The output of

8720-692: The south part of Turks Head Ridge. The bluff is 1.5 nautical miles (2.8 km; 1.7 mi) north-northeast of Turks Head. At the suggestion of P.R. Kyle, named by US-ACAN (2000) after Grazyna Zreda-Gostynska, who worked on Mount Erebus in 1989-90 as a member of the New Mexico Institute of Mining and Technology team. A Ph.D. student at NMIMT, she completed her doctoral dissertation on the gas emissions from Mount Erebus. 77°35′38″S 167°16′35″E  /  77.593989°S 167.276256°E  / -77.593989; 167.276256 . A broad north–south ridge, 4.5 nautical miles (8.3 km; 5.2 mi) long and 0.8 nautical miles (1.5 km; 0.92 mi) wide, on

8829-564: The south slopes of Mount Erebus. Completely ice covered, the ridge descends from about 2,200 metres (7,200 ft) high to 600 metres (2,000 ft) high, terminating 2.1 nautical miles (3.9 km; 2.4 mi) northwest of Tyree Head . In association with the names of expedition ships grouped on this island, named after United States Coast Guard Cutter (USCGC) Glacier , an icebreaker which for three decades, 1955-56 to 1986-87, supported scientific activity in Antarctica and Ross Sea on virtually an annual basis. From 1955-56, Glacier operated as

8938-690: The southeast margin of Turks Head Ridge. The bluff is 1.1 nautical miles (2.0 km; 1.3 mi) east-northeast of Grazyna Bluff. At the suggestion of P.R. Kyle, named by US-ACAN (2000) after Richard Esser, a member of New Mexico Tech field parties on Mount Erebus in the 1993-94 and 1994-95 seasons; later a technician in the New Mexico Geochronology Lab at NM Tech, where he has dated many rocks from Antarctica. 77°38′34″S 166°49′24″E  /  77.642825°S 166.823222°E  / -77.642825; 166.823222 . A rock bluff rising to about 600 metres (2,000 ft) high in

9047-406: The southern slopes of the mountain include: 77°32′S 166°53′E  /  77.533°S 166.883°E  / -77.533; 166.883 . An independent cone at an elevation of 1,800 metres (5,900 ft) high on the west slopes of Mount Erebus. From McMurdo Sound it appears as a perfect pyramid of black rock, standing out as a splendid mark against the background of the ice and almost on

9156-409: The southwest slope of the summit crater of Mount Erebus. So named because the ridge is defined by a series of fumarolic ice towers. 77°31′42″S 167°08′47″E  /  77.528236°S 167.146427°E  / -77.528236; 167.146427 . A concave slope, about 3,650 metres (11,980 ft) high, just south of Crystal Slope on the west side of the summit cone of Mount Erebus. The feature

9265-632: The southwest slopes of Mount Erebu. Named by members of the British Antarctic Expedition, 1910-13, under Scott. 77°38′S 166°49′E  /  77.633°S 166.817°E  / -77.633; 166.817 . A mostly ice-covered ridge extending from Turks Head for a few miles up the slopes of Mount Erebus. Mapped by the British Antarctic Expedition, 1910-13, under Scott and so named because of its association with Turks Head. 77°38′20″S 166°54′28″E  /  77.638772°S 166.90775°E  / -77.638772; 166.90775 . A rock bluff rising to about 600 metres (2,000 ft) high on

9374-435: The strongest seismic shaking. Strong motion sensors are used for intensity meter applications. Accelerographs and geophones are often heavy cylindrical magnets with a spring-mounted coil inside. As the case moves, the coil tends to stay stationary, so the magnetic field cuts the wires, inducing current in the output wires. They receive frequencies from several hundred hertz down to 1 Hz. Some have electronic damping,

9483-494: The summit of Mount Erebus on the southwest crater rim. Named for its location on the side of the main summit cone of Mount Erebus. 77°31′56″S 167°07′09″E  /  77.532253°S 167.119251°E  / -77.532253; 167.119251 A small circular crater at 3,561 metres (11,683 ft) high on the western slope of the summit of Mount Erebus. So named for its location. Download coordinates as: Mount Erebus has several named features on its slopes, including

9592-482: The summit of the volcano. So named because many working at the camp suffered from nausea due to high elevation mountain sickness. Features on the northern slopes include: 77°26′S 167°00′E  /  77.433°S 167.000°E  / -77.433; 167.000 . Pyramidal peak on the north side of Mount Erebus, between it and Mount Bird. Charted by the British Antarctic Expedition under Scott, 1910-13, and named for Petty Officer George P. Abbott, Royal Navy,

9701-497: The summit), on March 10, 1908. The ascent was documented in the first chapter of Aurora Australis , the first book to be written and published in Antarctica. Its first known solo ascent and the first winter ascent was accomplished by British mountaineer Roger Mear on 7 June 1985, a member of the "In the Footsteps of Scott" expedition. On 19–20 January 1991, Charles J. Blackmer, an iron-worker for many years at McMurdo Station and

9810-544: The surface brought in by animals (e.g. bats and birds) or ground water. The caves at Erebus are at high altitude, yet accessible for study. Some of the caves can reach temperatures of 25 degrees Celsius (77 degrees Fahrenheit), and with light near the cave mouths, in some caves covered by thin overlying ice the light reach even deeper, is sufficient to sustain an ecosystem of flora and fauna consisting of moss, algae, arthropods and nematodes. They are dynamic systems that collapse and rebuild, but persist over decades. The air inside

9919-664: The team of John Milne , James Alfred Ewing and Thomas Gray , who worked as foreign-government advisors in Japan, from 1880 to 1895. Milne, Ewing and Gray, all having been hired by the Meiji Government in the previous five years to assist Japan's modernization efforts, founded the Seismological Society of Japan in response to an Earthquake that took place on February 22, 1880, at Yokohama (Yokohama earthquake). Two instruments were constructed by Ewing over

10028-489: The temperature inside the volcano and the radioactivity of the materials present in such volcanoes. Dante successfully scaled a significant portion of the crater before technical difficulties emerged with the fibre-optic cable used for communications between the walker and base station. Since Dante had not yet reached the bottom of the crater, no data of volcanic significance was recorded. The expedition proved to be highly successful in terms of robotic and computer science, and

10137-455: The time the patent has expired, the design has been improved. The most successful public domain designs use thin foil hinges in a clamp. Another issue is that the transfer function of a seismograph must be accurately characterized, so that its frequency response is known. This is often the crucial difference between professional and amateur instruments. Most are characterized on a variable frequency shaking table. Another type of seismometer

10246-447: The volcano is also facilitated by its proximity to McMurdo Station (U.S.) and Scott Base (New Zealand), both sited on the same island around 35 km away. Mount Erebus is classified as a polygenetic stratovolcano . The bottom half of the volcano is a shield and the top half is a stratocone. The composition of the current eruptive products of Erebus are anorthoclase - porphyritic tephritic phonolite and phonolite , which are

10355-594: The volcano's emissions that include 80 grams of gold vapor daily. This amount of gold vapor is low compared to other volcanoes, but the condensation from vapor into gold particles is the first ever documented. Researchers spent more than three months during the 2007–08 field season installing an atypically dense array of seismometers around Mount Erebus to listen to waves of energy generated by small, controlled blasts from explosives they buried along its flanks and perimeter, and to record scattered seismic signals generated by lava lake eruptions and local ice quakes. By studying

10464-730: The volcanoes. Hainan Volcanic Field in China, San Pablo Volcanic Field in the Philippines, Ghegham Volcanic Ridge in Armenia, Dieng Volcanic Complex , in Indonesia, and Auckland Volcanic Field in New Zealand all have over 1 million people living within 5 kilometers (3.1 mi) of each volcano. Source: Source: Source: See list of volcanoes in Japan for more information Source: Source: Source: Seismometer A simple seismometer, sensitive to up-down motions of

10573-516: The weight stays unmoving, swinging the "gate" on the hinge. The advantage of a horizontal pendulum is that it achieves very low frequencies of oscillation in a compact instrument. The "gate" is slightly tilted, so the weight tends to slowly return to a central position. The pendulum is adjusted (before the damping is installed) to oscillate once per three seconds, or once per thirty seconds. The general-purpose instruments of small stations or amateurs usually oscillate once per ten seconds. A pan of oil

10682-661: The west slope of Mount Erebus. The feature is 0.6 nautical miles (1.1 km; 0.69 mi) southwest of Hoopers Shoulder. At the suggestion of P.R. Kyle, named by United States Advisory Committee on Antarctic Names (US-ACAN) (2000) after Katherine V. Cashman, United States Antarctic Research Program (USARP) team member on Mount Erebus in 1978-79 while a Fulbright scholar at Victoria University of Wellington; worked again on Mount Erebus, 1988-89; later Professor of Geology, University of Oregon. 77°35′S 166°47′E  /  77.583°S 166.783°E  / -77.583; 166.783 . A prominent rock cliff that stands out from

10791-617: The world, 500 of which have erupted in historical time. Many active volcanoes are located along the Pacific Rim, also known as the Pacific Ring of Fire . An estimated 500 million people live near active volcanoes. Historical time (or recorded history) is another timeframe for active . The span of recorded history differs from region to region. In China and the Mediterranean , it reaches back nearly 3,000 years, but in

10900-546: Was an earthquake, one of the dragons' mouths would open and drop its ball into a bronze toad at the base, making a sound and supposedly showing the direction of the earthquake. On at least one occasion, probably at the time of a large earthquake in Gansu in AD 143, the seismoscope indicated an earthquake even though one was not felt. The available text says that inside the vessel was a central column that could move along eight tracks; this

11009-420: Was an inverted pendulum seismometer constructed by James David Forbes , first presented in a report by David Milne-Home in 1842, which recorded the measurements of seismic activity through the use of a pencil placed on paper above the pendulum. The designs provided did not prove effective, according to Milne's reports. It was Milne who coined the word seismometer in 1841, to describe this instrument. In 1843,

11118-528: Was attempted, but his final design did not fulfill his expectations and suffered from the same problems as the Forbes design, being inaccurate and not self-recording. Karl Kreil constructed a seismometer in Prague between 1848 and 1850, which used a point-suspended rigid cylindrical pendulum covered in paper, drawn upon by a fixed pencil. The cylinder was rotated every 24 hours, providing an approximate time for

11227-423: Was constructed in 'Earthquake House' near Comrie, which can be considered the world's first purpose-built seismological observatory. As of 2013, no earthquake has been large enough to cause any of the cylinders to fall in either the original device or replicas. The first seismographs were invented in the 1870s and 1880s. The first seismograph was produced by Filippo Cecchi in around 1875. A seismoscope would trigger

11336-424: Was cook and camp manager at the lower Erebus Hut during the 1992-93 NSF-NASA Dante robot experiment on Mount Erebus. She also managed the food room at McMurdo Station, was the hovercraft pilot, and has also been a helicopter technician. 77°28′41″S 166°53′17″E  /  77.478006°S 166.888183°E  / -77.478006; 166.888183 A nunatak rising to about 1,700 metres (5,600 ft) high on

11445-599: Was created by an explosive VEI -6 eruption that occurred 18,000 ± 7,000 years ago. It is filled with small volume tephritic phonolite and phonolite lava flows. In the center of the summit caldera is a small, steep-sided cone composed primarily of decomposed lava bombs and a large deposit of anorthoclase crystals known as Erebus crystals . The active lava lake in this summit cone undergoes continuous degassing. Microscopic gold particles have been found up to 1000 kilometers from Mount Erebus, ranging in size up to 60 micrometres. A 1991 paper shows that these particles condense from

11554-629: Was made in China during the 2nd century. It was invented by Zhang Heng , a Chinese mathematician and astronomer. The first Western description of the device comes from the French physicist and priest Jean de Hautefeuille in 1703. The modern seismometer was developed in the 19th century. Seismometers were placed on the Moon starting in 1969 as part of the Apollo Lunar Surface Experiments Package . In December 2018,

11663-709: Was possibly the first expedition by a robotic platform to Antarctica. Air New Zealand Flight 901 was a scheduled sightseeing service from Auckland Airport in New Zealand to Antarctica and return with a scheduled stop at Christchurch Airport to refuel before returning to Auckland. The Air New Zealand flyover service, for the purposes of Antarctic sightseeing, was operated with McDonnell Douglas DC-10-30 aircraft and began in February 1977. The flight crashed into Mount Erebus on November 28, 1979, killing all 257 people on board. Passenger photographs taken seconds before

11772-649: Was the young Joseph Hooker , future president of the Royal Society and close friend of Charles Darwin . Erebus is a dark region in Hades in Greek mythology , personified as the Ancient Greek primordial deity of darkness, the son of Chaos . The mountain was surveyed in December 1912 by a science party from Robert Falcon Scott 's Terra Nova expedition , who also collected geological samples. Two of

11881-414: Was used as the access route from a NASA robot called Dante that was carried to the crater rim, Jan. 1, 1993. 77°31′32″S 167°09′01″E  /  77.52563°S 167.150153°E  / -77.52563; 167.150153 . A western slope, 3,700 metres (12,100 ft) high, between Camp Slope and Robot Gully, leading down from the summit crater rim of Mount Erebus. So named because the slope includes

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