Melihat kerusakan Pasca bencana Padang melalui udara

saya sangat berduka atas terjadi sebuah bencana yang menimpa tanah air yang saya cintai dan saya sayangi ini, semoga kepada para korban bencana ini dapat kuat secara batin dan fisik, sehingga dapat menggambil sebuah kemenangan besar di balik bencana ini , kali ini saya akan menyajikan sebuah hasil udara yang mengidentifikasikan kerusakan dari The “Center for Satellite Based Crisis Information” (ZKI) Jerman yaitu gambar di bawah ini


Peta-peta tematik tersebut juga telah menjadi salah satu acuan tim dari Inisiatif RSGISForum untuk bencana Sumatera Barat. Gambar diatas adalah satu produk hasil peta yang dirilis oleh ZKI. Tampak warna kuning adalah adalah bangunan yang berpotensi rusak dilihat dari image satelit, warna merah adalah bangunan yang berpotensi rusak dilihat dari stukturnya, sementara warna hitam adalah bangunan rusak seperti yang dilaporkan oleh Badan Nasional Penanggulangan Bencana (BNPB) (lihat gambar legend dibawah ini).

source : http://inigis.info/blog/peta-kerusakan-kota-padang-setelah-gempa/
www.amiboyz.com

Long Debate Ended Over Cause, Demise Of Ice Ages? Research Into Earth's Wobble

ScienceDaily (Aug. 7, 2009) — Researchers have largely put to rest a long debate on the underlying mechanism that has caused periodic ice ages on Earth for the past 2.5 million years – they are ultimately linked to slight shifts in solar radiation caused by predictable changes in Earth's rotation and axis.
In a publication to be released Friday in the journal Science, researchers from Oregon State University and other institutions conclude that the known wobbles in Earth's rotation caused global ice levels to reach their peak about 26,000 years ago, stabilize for 7,000 years and then begin melting 19,000 years ago, eventually bringing to an end the last ice age.

The melting was first caused by more solar radiation, not changes in carbon dioxide levels or ocean temperatures, as some scientists have suggested in recent years.

"Solar radiation was the trigger that started the ice melting, that's now pretty certain," said Peter Clark, a professor of geosciences at OSU. "There were also changes in atmospheric carbon dioxide levels and ocean circulation, but those happened later and amplified a process that had already begun."

The findings are important, the scientists said, because they will give researchers a more precise understanding of how ice sheets melt in response to radiative forcing mechanisms. And even though the changes that occurred 19,000 years ago were due to increased solar radiation, that amount of heating can be translated into what is expected from current increases in greenhouse gas levels, and help scientists more accurately project how Earth's existing ice sheets will react in the future.

"We now know with much more certainty how ancient ice sheets responded to solar radiation, and that will be very useful in better understanding what the future holds," Clark said. "It's good to get this pinned down."

To make their analysis, the researchers used an analysis of 6,000 dates and locations of ice sheets to define, with a high level of accuracy, when they started to melt. In doing this, they confirmed a theory that was first developed more than 50 years ago that pointed to small but definable changes in Earth's rotation as the trigger for ice ages.

"We can calculate changes in the Earth's axis and rotation that go back 50 million years," Clark said. "These are caused primarily by the gravitational influences of the larger planets, such as Jupiter and Saturn, which pull and tug on the Earth in slightly different ways over periods of thousands of years."

That, in turn, can change the Earth's axis – the way it tilts towards the sun – about two degrees over long periods of time, which changes the way sunlight strikes the planet. And those small shifts in solar radiation were all it took to cause multiple ice ages during about the past 2.5 million years on Earth, which reach their extremes every 100,000 years or so.

Sometime around now, scientists say, the Earth should be changing from a long interglacial period that has lasted the past 10,000 years and shifting back towards conditions that will ultimately lead to another ice age – unless some other forces stop or slow it. But these are processes that literally move with glacial slowness, and due to greenhouse gas emissions the Earth has already warmed as much in about the past 200 years as it ordinarily might in several thousand years, Clark said.

"One of the biggest concerns right now is how the Greenland and Antarctic ice sheets will respond to global warming and contribute to sea level rise," Clark said. "This study will help us better understand that process, and improve the validity of our models."

The research was done in collaboration with scientists from the Geological Survey of Canada, University of Wisconsin, Stockholm University, Harvard University, the U.S. Geological Survey and University of Ulster. It was supported by the National Science Foundation and other agencies.

Pergerakan Gunung

Dalam sebuah ayat, kita diberitahu bahwa gunung-gunung tidaklah diam sebagaimana yang tampak, akan tetapi mereka terus-menerus bergerak.
"Dan kamu lihat gunung-gunung itu, kamu sangka dia tetap di tempatnya, padahal dia berjalan sebagai jalannya awan. (Begitulah) perbuatan Allah yang membuat dengan kokoh tiap-tiap sesuatu; sesungguhnya Allah Maha Mengetahui apa yang kamu kerjakan." (Al Qur'an, 27:88)
Gerakan gunung-gunung ini disebabkan oleh gerakan kerak bumi tempat mereka berada. Kerak bumi ini seperti mengapung di atas lapisan magma yang lebih rapat. Pada awal abad ke-20, untuk pertama kalinya dalam sejarah, seorang ilmuwan Jerman bernama Alfred Wegener mengemukakan bahwa benua-benua pada permukaan bumi menyatu pada masa-masa awal bumi, namun kemudian bergeser ke arah yang berbeda-beda sehingga terpisah ketika mereka bergerak saling menjauhi.

Para ahli geologi memahami kebenaran pernyataan Wegener baru pada tahun 1980, yakni 50 tahun setelah kematiannya. Sebagaimana pernah dikemukakan oleh Wegener dalam sebuah tulisan yang terbit tahun 1915, sekitar 500 juta tahun lalu seluruh tanah daratan yang ada di permukaan bumi awalnya adalah satu kesatuan yang dinamakan Pangaea. Daratan ini terletak di kutub selatan.
Sekitar 180 juta tahun lalu, Pangaea terbelah menjadi dua bagian yang masing-masingnya bergerak ke arah yang berbeda. Salah satu daratan atau benua raksasa ini adalah Gondwana, yang meliputi Afrika, Australia, Antartika dan India. Benua raksasa kedua adalah Laurasia, yang terdiri dari Eropa, Amerika Utara dan Asia, kecuali India. Selama 150 tahun setelah pemisahan ini, Gondwana dan Laurasia terbagi menjadi daratan-daratan yang lebih kecil.
Benua-benua yang terbentuk menyusul terbelahnya Pangaea telah bergerak pada permukaan Bumi secara terus-menerus sejauh beberapa sentimeter per tahun. Peristiwa ini juga menyebabkan perubahan perbandingan luas antara wilayah daratan dan lautan di Bumi.
Pergerakan kerak Bumi ini diketemukan setelah penelitian geologi yang dilakukan di awal abad ke-20. Para ilmuwan menjelaskan peristiwa ini sebagaimana berikut:
Kerak dan bagian terluar dari magma, dengan ketebalan sekitar 100 km, terbagi atas lapisan-lapisan yang disebut lempengan. Terdapat enam lempengan utama, dan beberapa lempengan kecil. Menurut teori yang disebut lempeng tektonik, lempengan-lempengan ini bergerak pada permukaan bumi, membawa benua dan dasar lautan bersamanya. Pergerakan benua telah diukur dan berkecepatan 1 hingga 5 cm per tahun. Lempengan-lempengan tersebut terus-menerus bergerak, dan menghasilkan perubahan pada geografi bumi secara perlahan. Setiap tahun, misalnya, Samudera Atlantic menjadi sedikit lebih lebar. (Carolyn Sheets, Robert Gardner, Samuel F. Howe; General Science, Allyn and Bacon Inc. Newton, Massachusetts, 1985, s. 30)
Ada hal sangat penting yang perlu dikemukakan di sini: dalam ayat tersebut Allah telah menyebut tentang gerakan gunung sebagaimana mengapungnya perjalanan awan. (Kini, Ilmuwan modern juga menggunakan istilah "continental drift" atau "gerakan mengapung dari benua" untuk gerakan ini. (National Geographic Society, Powers of Nature, Washington D.C., 1978, s.12-13)
Tidak dipertanyakan lagi, adalah salah satu kejaiban Al Qur’an bahwa fakta ilmiah ini, yang baru-baru saja ditemukan oleh para ilmuwan, telah dinyatakan dalam Al Qur’an.
Sumber : www.keajaibanalquran.com

Sumatra Earthquake Three Times Larger Than Originally Thought

ScienceDaily (Feb. 12, 2005) — EVANSTON, Ill. --- Northwestern University seismologists have determined that the Dec. 26 Sumatra earthquake that set off a deadly tsunami throughout the Indian Ocean was three times larger than originally thought, making it the second largest earthquake ever instrumentally recorded and explaining why the tsunami was so destructive.

By analyzing seismograms from the earthquake, Seth Stein and Emile Okal, both professors of geological sciences in Northwestern's Weinberg College of Arts and Sciences, calculated that the earthquake's magnitude measured 9.3, not 9.0, and thus was three times larger. These results have implications for why Sri Lanka suffered such a great impact and also indicate that the chances of similar large tsumanis occurring in the same area are reduced.
By analyzing seismograms from the earthquake, Seth Stein and Emile Okal, both professors of geological sciences in Northwestern's Weinberg College of Arts and Sciences, calculated that the earthquake's magnitude measured 9.3, not 9.0, and thus was three times larger. These results have implications for why Sri Lanka suffered such a great impact and also indicate that the chances of similar large tsumanis occurring in the same area are reduced.

"The rupture zone was much larger than previously thought," said Stein. "The initial calculations that it was a 9.0 earthquake did not take into account what we call slow slip, where the fault, delineated by aftershocks, shifted more slowly. The additional energy released by slow slip along the 1,200-kilometer long fault played a key role in generating the devastating tsunami."

The large tsunami amplitudes that occurred in Sri Lanka and India, said tsunami expert Okal, result from rupture on the northern, north-trending segment of the fault -- the area of slow slip -- because tsunami amplitudes are largest perpendicular to the fault.

Because the entire rupture zone slipped (both fast and slow slip fault areas), strain accumulated from subduction of the Indian plate beneath the Burma microplate has been released, leaving no immediate danger of a comparable ocean-wide tsunami being generated on this segment of the plate boundary. However, the danger of a local tsunami due to a powerful aftershock or a large tsunami resulting from a great earthquake on segments to the south remains.

The analysis technique used by Stein and Okal to extract these data from the earth's longest period vibrations (normal modes) relied on results developed by them and colleague Robert Geller (now at the University of Tokyo) in their graduate studies almost 30 years ago. However, because such gigantic earthquakes are rare, these methods had been essentially unused until records of the Sumatra earthquake on modern seismometers became available.

The largest earthquake ever recorded, which measured 9.5, was in Chile on May 22, 1960.

How Floods Work

by Tom Harris

Air merupakan bagian yang sangat penting dalam kehidupan umat manusia. Dengan air kita dapat minum, mandi atau bahkan untuk masak makanan. Tapi jika dapat kuantitas sangat besar dapat mengulingkan mobil, merobohkan rumah dan bahkan dapat membunuh manusia.




Flooding has claimed millions of lives in the last hundred years alone, more than any other weather phenomenon. Hurricane Katrina in New Orleans and the 2008 cyclone that struck Myanmar are recent examples of the widespread devastation that flooding can incur.

In this article, we'll find out what makes water change character so rapidly and see what happens when it does. We'll explore the negative impact of floods as well as some of the benefits. We'll also examine how human construction can contain flooding or, in some cases, cause it.

Water, Water Everywhere

To understand how floods work, you have to know something about how water behaves on our planet. The total amount of water on Earth has remained fairly constant for millions of years (though its distribution has varied considerably in that time). Every day, a very small amount of water is lost high in the atmosphere, where intense ultraviolent rays can break a water molecule apart, but new water is also emitted from the inner part of the Earth, by volcanic activity. The amount of water that is created and the amount that is lost are pretty much equal.

At any one time, this volume of water is in many different forms. It can be liquid, as in oceans, rivers and rain; solid, as in the glaciers of the North and South Poles; or gaseous, as in the invisible water vapor in the air. Water changes from state to state as it is moved around the planet by wind currents. Wind currents are generated by the heating activity of the sun. The sun shines more on the area around Earth's equator than it does on areas farther north and south, causing a heat discrepancy over the surface of the globe. In warmer regions, hot air rises up into the atmosphere, pulling cooler air into the vacated space. In cooler regions, cold air sinks, pulling warmer air into the vacated space. The rotation of the Earth breaks this cycle up, so there are several, smaller air-current cycles all along the globe.

Driven by these air-current cycles, Earth's water supply moves in a cycle of its own. When the sun heats the oceans, liquid water from the ocean's surface evaporates into water vapor in the air. The sun heats this air (water vapor and all) so that it rises through the atmosphere and is carried along by wind currents. As this water vapor rises, it cools down again, condensing into droplets of liquid water (or crystals of solid ice). Collections of these droplets are called clouds. If a cloud moves into a cooler environment, more water may condense onto these droplets. If enough water accumulates in this way, the droplets become heavy enough that they fall through the air as precipitation (rain, snow, sleet or hail). Some of this water collects in large, underground reservoirs, but most of it forms rivers and streams that flow into the oceans, bringing the water back to its starting point.

Overall, wind currents in the atmosphere are fairly consistent. At any particular time of year, currents tend to move in a certain way across the globe. Consequently, specific locations generally experience the same sort of weather conditions year to year. But on a day-to-day basis, the weather is not so predictable. Wind currents and precipitation are affected by many factors, chiefly geography and neighboring weather conditions. A huge number of factors combine in an infinite variety of ways, producing all sorts of weather. Occasionally, these factors interact in such a way that an atypical volume of liquid water collects in one area. For example, conditions occasionally cause the formation of a hurricane, which dumps a large quantity of rain wherever it goes. If a hurricane lingers over a region, or multiple hurricanes happen to move through the area, the land receives much more precipitation than normal.

Since waterways are formed slowly over time, their size is proportionate to the amount of water that normally accumulates in that area. When there is suddenly a much greater volume of water, the normal waterways overflow, and the water spreads out over the surrounding land. At its most basic level, this is what a flood is -- an anomalous accumulation of water in an area of land.

A series of storms bringing massive amounts of rain is the most common cause of flooding, but there are others. In the next section, we'll look at some of the ways floods start, as well as some of the factors that determine their magnitude.

World's Most Unusual Volcano: Origin Of Carbon-based Lavas Revealed

ScienceDaily (May 7, 2009) — Scientists studying the world's most unusual volcano have discovered the reason behind its unique carbon-based lavas. The new geochemical analyses reveals that an extremely small degree of partial melting of typical minerals in the earth's upper mantle is the source of the rare carbon-derived lava erupting from Tanzania's Oldoinyo Lengai volcano.
Although carbon-based lavas, known as carbonatites, are found throughout history, the Oldoinyo Lengai volcano, located in the East African Rift in northern Tanzania, is the only place on Earth where they are actively erupting. The lava expelled from the volcano is highly unusual in that it contains almost no silica and greater than 50 percent carbonate minerals. Typically lavas contain high levels of silica, which increases their melting point to above 900°C (1652°F). The lavas of Oldoinyo Lengai volcano erupt as a liquid at approximately 540°C (1004°F). This low silica content gives rise to the extremely fluid lavas, which resembles motor oil when they flow.

A team of scientists from University of New Mexico, Scripps Institution of Oceanography at UC San Diego and Centre de Recherches Petrographiques et Geochimiques in Nancy, France, report new findings of volcanic gas emissions in a paper published in the May 7 issue of the journal Nature.

"The chemistry and isotopic composition of the gases reveal that the CO2 is directly sourced from the upper mantle below the East African Rift," said David Hilton, professor of geochemistry at Scripps Institution of Oceanography at UC San Diego and coauthor of the paper. "These mantle gases allow us to infer the carbon content of the upper mantle that is producing the carbonatites to be around 300 parts per million, a concentration that is virtually identical to that measured below mid-ocean ridges."

Mid-ocean ridges are underwater mountain ranges where the seafloor is spreading due to tectonic plates moving away from one another. Rift valleys, such as the one where Oldoinyo Lengai volcano is located, and mid-ocean ridges are considered to be distinct tectonic regions. However, this study has shown that their chemistries are identical, which led the scientists to suggest that the carbon contents of their mantle sources were not different but due to partial melting of typical minerals located in the earth's mantle.

"Since the volcano was under magma pressure during the eruption, we were able to collect pristine samples of the volcanic gases, with minimal air contamination," said Tobias Fischer, volcanologist at the University of New Mexico. The pristine samples collected during a 2005 eruption offered the scientists a deeper look at the processes taking place in the earth's upper mantle.

The geochemical analyses, some of which were conducted at Hilton's geochemical lab at Scripps Oceanography, revealed that magma from the upper mantle below both the oceans and continents is a uniform and well-mixed reservoir of "typical" volcanic gases such as carbon dioxide, nitrogen, argon and helium.

The lava expelled from the volcano is highly unusual in that it contains almost no silica and greater than 50 percent carbonate minerals. Typically lavas contain high levels of silica, which increases their melting point to above 900°C (1652°F). The lavas of Oldoinyo Lengai volcano are comprised of carbonatites, which erupts as a liquid at approximately 540°C (1004°F). This low silica content gives rise to the extremely fluid lavas, which resembles motor oil when they flow.

"These finding are significant because it shows that these extremely bizarre lavas and their parent magmas, nephelinites, were produced by melting of a typical upper mantle mineral assemblage without an extreme carbon content in the magma source," said geochemist Bernard Marty at the Centre de Recherches Petrographiques et Geochimiques in Nancy, France. "Rather, in order to make carbonatite lavas, all you need is a very low melt fraction of 0.3 percent or less."

Oldoinyo Lengai, like all volcanoes, emits carbon dioxide into the atmosphere as a gas. However, Lengai's magma is unusual in that it also contains high sodium contents. About one percent of the mantle-derived carbon emitted from Lengai goes into the carbonatite melt with the remainder being emitted into the atmosphere as CO2 gas. The CO2 released into the atmosphere by volcanoes worldwide is a small fraction when compared to man-made emissions.

Ilmu Geologi

Geologi (berasal dari Yunani γη- (ge-, "bumi") dan λογος (logos, "kata", "alasan")) adalah Ilmu (sains yang mempelajari bumi, komposisinya, struktur, sifat-sifat fisik, sejarah, dah proses yang membentuknya.

Geologiwan telah membantu dalam menentukan umur Bumi yang diperkirakan sekitar 4.5 milyar (4.5x109) tahun, dan menentukan bahwa kulit bumi terpecah menjadi lempeng tektonik yang bergerak di atas mantel yang setengah cair (astenosfir) melalui proses yang sering disebut tektonik lempeng. Geologiwan membantu menemukan dan mengatur sumber daya alam yang ada di bumi, seperti minyak bumi, batu bara, dan juga metal seperti besi, tembaga, dan uranium serta mineral lainnya yang memiliki nilai ekonomi, seperti asbestos, perlit, mika, fosfat, zeolit, tanah liat, pumis, kuarsa, dan silika, dan juga elemen lainnya seperti belerang, klorin, dan helium.



Astrogeologi adalah aplikasi ilmu geologi tentang planet lainnya dalam tata surya (solar sistem). Namun istilah khusus lainnya seperti selenology (pelajaran tentang bulan), areologi (pelajaran tentang planet Mars), dll, juga dipakai.

Kata "geologi" pertama kali digunakan oleh Jean-André Deluc dalam tahun 1778 dan diperkenalkan sebagai istilah yang baku oleh Horace-Bénédict de Saussure pada tahun 1779.

Sejarah pembentukan Bumi

pemikiran manusia untuk memikirkan pembentukan bumi atau dalam skala besar itu pembentukan alam semesta adalah anugerah yang diberikan ALLAH SWT kepada umat manusia.
Seperti guru kita berkata pertanyaan yang terbaik dalam diri kita adalah

Darimana kita berasal ?
Apa tujuan kita sekarang ?
Akan kemanakah kita setelah sekarang ?

Berikut adalah penjelasan secara singkat dari pembentukan bumi.
yang diilhami dari pertanyaan dariman kita berasal?

Saya rangkum dalam bentuk pptx (microsoft office 2007) sebagai berikut:

Sejarah pembentukan bumi

atau dalam bentuk pdf

sejarah pembentukan bumi

Dan tolong komentarnya dari teman-teman.