Plane Table Survey

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Theodolite Survey

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Surveying

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Chain Survey

Chain Survey
Chain survey is the simplest method of surveying. In this survey only measurements are taken in the field, and the rest work, such as plotting calculation etc. are done in the office. This is most suitable adapted to small plane areas with very few details. If carefully done, it gives quite accurate results. The necessary requirements for field work are chain, tape, ranging rod, arrows and some time cross staff.
Survey Station:
Survey stations are of two kinds
  1. Main Stations
  2. Subsidiary or tie
Main Stations:
Main stations are the end of the lines, which command the boundaries of the survey, and the lines joining the main stations re called the main survey line or the chain lines.
Subsidiary or the tie stations:
Subsidiary or the tie stations are the point selected on the main survey lines, where it is necessary to locate the interior detail such as fences, hedges, building etc.
Tie or subsidiary lines:
A tie line joints two fixed points on the main survey lines. It helps to checking the accuracy of surveying and to locate the interior details. The position of each tie line should be close to some features, such as paths, building etc.
Base Lines:
It is main and longest line, which passes approximately through the centre of the field. All the other measurements to show the details of the work are taken with respect of this line.
Check Line:
A check line also termed as a proof line is a line joining the apex of a triangle to some fixed points on any two sides of a triangle. A check line is measured to check the accuracy of the framework. The length of a check line, as measured on the ground should agree with its length on the plan.
Offsets:
These are the lateral measurements from the base line to fix the positions of the different objects of the work with respect to base line. These are generally set at right angle offsets. It can also be drawn with the help of a tape. There are two kinds of offsets:
1) Perpendicular offsets, and
2) Oblique offsets.

The measurements are taken at right angle to the survey line called perpendicular or right angled offsets.
The measurements which are not made at right angles to the survey line are called oblique offsets or tie line offsets.
Procedure in chain survey:
1. Reconnaissance:
The preliminary inspection of the area to be surveyed is called reconnaissance. The surveyor inspects the area to be surveyed, survey or prepares index sketch or key plan.
2. Marking Station:
Surveyor fixes up the required no stations at places from where maximum possible stations are possible.
3. Then he selects the way for passing the main line, which should be horizontal and clean as possible and should pass approximately through the centre of work.
4. Then ranging roads are fixed on the stations.
5. After fixing the stations, chaining could be started.
6. Make ranging wherever necessary.
7. Measure the change and offset.
8. Enter in the field the book.



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Deadliest Earthquakes on Record



(50,000 deaths or more)


The following table lists the deadliest earthquakes on record according to date, location, number of deaths, and magnitude. On Jan. 23, 1556, an 8.0 magnitude earthquake struck Shansi, China killing 830,000 people.
Date
Location
Deaths
Magnitude
Jan. 23, 1556
Shansi, China
830,000
~8
July 27, 1976
Tangshan, China
255,0001
7.5
Aug. 9, 1138
Aleppo, Syria
230,000
n.a.
Dec. 26, 2004
off west coast of northern Sumatra
225,000+
9.0
Jan. 12, 2010
Haiti
222,570
7.0
Dec. 22, 8562
Damghan, Iran
200,000
n.a.
May 22, 1927
near Xining, Tsinghai, China
200,000
7.9
Dec. 16, 1920
Gansu, China
200,000
7.8
March 23, 8932
Ardabil, Iran
150,000
n.a.
Sept. 1, 1923
Kwanto, Japan
143,000
7.9
Oct. 5, 1948
Ashgabat, Turkmenistan, USSR
110,000
7.3
Dec. 28, 1908
Messina, Italy
70,000–
100,000
3
7.2
Sept. 1290
Chihli, China
100,000
n.a.
May 12, 2008
Eastern Sichuan, China
87,587
7.9
Oct. 8, 2005
Pakistan
 80,361
7.6
Nov. 1667
Shemakha, Caucasia
 80,000
n.a.
Nov. 18, 1727
Tabriz, Iran
 77,000
n.a.
Dec. 25, 1932
Gansu, China
 70,000
7.6
Nov. 1, 1755
Lisbon, Portugal
 70,000
8.7
May 31, 1970
Peru
 66,000
7.9
May 30, 1935
Quetta, Pakistan
 30,000–
 60,000
7.5
Jan. 11, 1693
Sicily, Italy
 60,000
n.a.
12684
Silicia, Asia Minor
 60,000
n.a.
June 20, 1990
Iran
 50,000
7.7
Feb. 4, 1783
Calabria, Italy
 50,000
n.a.
1. Official. Estimated death toll as high as 655,000.
2. Note that these dates are prior to A.D. 1000. No digit is missing.
3. Estimated.
4. No date available.
Source: National Earthquake Information Center, U.S. Geological Survey. Data compiled from several sources.

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Recent Volcanic Activity


The following table shows the recent and ongoing volcanic history around the world by year of activity and volcano name.
(Bold indicates activity in 2008, 2009, and 2010)


VolcanoYear of last
eruption
or activity
Adatara, Honshu, Japan1997
Akan, Hokkaido, Japan2006
Akutan, Alaska1996
Ambrym Island, Vanuatu2007
Amukta, Alaska1996
Anatahan, Mariana Islands2007
Aoba, Ambae Island, Vanuatu2006
Arenal, Costa Ricaongoing
Asama, Honshu, Japan2003
Aso, Kyushu, Japan2004
Atka, Aleutian Islands, United States2006
Augustine, Cook Inlet, Alaska, United States2006
Axial Seamount1998
Bamus, New Britain Island, Papua New Guinea2006
Bandai, Honshu, Japan2000
Bagana, Bougainville, Papua New Guineaongoing
Barren Island, Indian Ocean2008
Batu Tara, Lesser Sunda Islands, Indonesia2007
Bezymianny, Kamchatka, Russia2009
Bromo, Java, Indonesia2000
Bulusan, Philippines2007
Mount Cameroon, Cameroon2000
Canlaon, Philippines2006
Cerro Azul, Galápagos Islands, Ecuador1998
Cerro Negro, Nicaragua1999
Chaitén, Chile2008
Chikurachki, Kurile Islands, Russia2005
Chiginagak, Alaska1997
Chuginadak, Alaska2005
Cleveland, Chuginadak Island, Alaska2008
Colima, Mexicoongoing
Conception, Island of Ometepe, Nicaragua2010
Copahue, Argentina and Chile2000
Dempo, Sumatra Indonesia2006
Dukono, Indonesiaongoing
East Epi, Vanuatu2004
Eastern Gemini Seamount, Vanuatu1996
Ebeko, Kuril Islands, Russia2007
Egoni, Indonesia2004
Erta Ale, Ethiopia2003
Etna, Sicily, Italy2007
Eyjafjallajokull, Iceland2010
Fernandina, Galápagos1995
Fogo, Cape Verde1995
Piton de la Fournaise, France2010
Fourpeaked, Alaska Peninsula, United States2006
Fuego, Guatemalaongoing
Fukutoku-Okanoba, Japan2010
Galeras, Colombia2008
Gamalama, Indonesia2003
Gaua, Vanuatu2009
Grimsvotn, Iceland1998
Guagua Pichincha, Ecuador2006
Hachijo-Jima, Izu Islands, Japan2002
Hakkoda, Japan1997
Heard Island, Southern Indian Ocean, Australia2006
Hekla, Iceland2000
Mount Hili Aludo, Indonesia1997
Hokkaido, Japan2006
Home Reef, Tonga Islands, Tonga2006
Hosho, Kyushu, Japan1995
Ijen, Java, Indonesia2001
Iwate-san, Honshu, Japan1998
Jackson Segment, N. Gorda Ridge (nr. Oregon)2001
Kaba, Sumatra, Indonesia2000
Mount Karangetang, Indonesia2007
Karthala, Comoros Islands, Indian Ocean2007
Karymsky, Kamchatka, Russiaongoing
Kavachi Seamount, Solomon Islands2004
Kelut, Java, Indonesia2006
Kick-'em-Jenny (nr. Grenada)2003
Kikai, Japan2004
Kilauea, Hawaiiongoing
Kirishima, Japan2010
Kliuchevskoi, Kamchatka, Russia2009
Komagatake, Hokkaido, Japan2000
Korovin, Alaska1998
Krakatau, Indonesia2001
Langila, New Britain, P.N.G.2007
Lamongan, Indonesia2003
Lascar, Chile2007
Leroboleng, Indonesia2003
Mount Lewotobi, Indonesia2003
Llaima, Chile2008
Loihi Seamount, Hawaii1996
Lokon, Sulawesi, Indonesia2003
Long Valley caldera, California1996
Lopevi, Central Islands, Vanuatu2007
La Madera, Nicaragua1996
Manam, Papua New Guineaongoing
Maroa, New Zealand2001
Masaya, Nicaraguaongoing
Mauna Loa, Hawaii2003
Mayon, Philippines2009
McDonald Island, Australia1996
Merapi, Indonesia2007
Metis Shoal, Tonga1995
Momotombo, Nicaragua1996
Monowai Seamount, Kermadec Islands1997
Nevado Del Huila, Colombia2007
Nyamuragira, Congo (Dem. Rep.)2010
Nyiragongo, Congo (Dem. Rep.)2003
Okmok, Alaska1997
Ol Doinya Lengai, Tanzania, Africa2006
Oyama, Miyake-jima, Izu Islands, Japan2006
Pacaya, Guatemala2007
Pagan, Mariana Islands, central Pacific Ocean2006
Pago, Papua New Guinea2004
Papandayan, Java, Indonesia2002
Pavlof, Alaska1997
Peuet Sague, Indonesia1998
Piparo, Trinidad1997
Piton de la Fournaise, Réunion2007
Poas, Costa Rica2006
Popocatepetl, Mexico2007
Rabaul, Papua New Guinea2008
Raoul Island, New Zealand2006
Redoubt, Alaska2009
Reventador, Ecuador2007
Rincon de la Vieja, Costa Rica1998
Ritter Island, Papua New Guinea2006
Rotorua, New Zealand2001
Ruapehu, New Zealand2006
Ruby Seamount, Mariana Islands1995
Mount St. Helens, Washingtonongoing
Sakura-Jima, Japanongoing
San Cristobal, Nicaragua2006
San Miguel, El Salvador2006
Sangay, Ecuadorongoing
Santa Ana, El Salvador2006
Santa Maria, Guatemalaongoing
Semeru, Java, Indonesiaongoing
Shiveluch, Kamchatka, Russiaongoing
Shin-dake, Kuchinoerabujima Island, Japan1999
Shishaldin, Unimak Island, Alaska2000
Simbo, Solomon Islands2006
Slamet, Java Indonesia2007
Soputan, Indonesia2006
Soufriere Hills, Montserrat, West Indiesongoing
South Sister, Oregon2001
Stromboli, Italyongoing
Sulu Range, New Britain Island, Papua New Guinea2006
Suwanose-Jima Ryukyu Islands, Japanongoing
Tavurvur, Papua New Guinea2000
Taal, Philippines2006
Talang, Indonesia2007
Telica, Nicaragua2007
Tengger Caldera, Java, Indonesia2006
Terceira, Azores1999
Tonga (unnamed volcano)1999
Tongariro Volcanic Centre, New Zealand2006
Tungurahua, Ecuadorongoing
Turrialba, Costa Rica2010
Ubinas, Peru2007
Ulawun, Papua New Guinea2007
Usu, Japan2000
Veniaminof, Alaska2006
Villarrica, Chile2009
White Island, New Zealand2007
Yasur, Tanna Island, Vanuatu2004
Yellowstone, Wyoming1998
Zacatecas, Mexico1997
Source: Global Volcanism Program. Web: volcano.und.edu/vw.html .


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