Tuesday, October 02, 2007

Yvonne Ridley: From captive to convert

Yvonne Ridley: From captive to convert

Yvonne Ridley at the Medina Mosque, Southampton
Ridley: "The Koran makes it crystal clear that women are equal"
If you were being interrogated by the Taleban as a suspected US spy, it might be hard to imagine a happy ending.

But for journalist Yvonne Ridley, the ordeal in Afghanistan led her to convert to a religion she says is "the biggest and best family in the world".

The formerly hard-drinking Sunday school teacher became a Muslim after reading the Koran on her release.

She now describes radical cleric Abu Hamza al-Masri as "quite sweet really" and says the Taleban have suffered an unfair press.

Working as a reporter for the Sunday Express in September 2001, Ridley was smuggled from Pakistan across the Afghan border.

Afghanistan was about to be bombed and all [the Taleban] were concerned about was my big knickers
Yvonne Ridley

But her cover was blown when she fell off her donkey in front of a Taleban soldier near Jalalabad, revealing a banned camera underneath her robes.

Her first thought as the furious young man came running towards her?

"Wow - you're gorgeous," she says.

"He had those amazing green eyes that are peculiar to that region of Afghanistan and a beard with a life of its own.

"But fear quickly took over. I did see him again on my way to Pakistan after my release and he waved at me from his car."

Yvonne Ridley before her conversion to Islam. Portrait by Jeff Overs
Ridley was working for the Sunday Express at the time of her capture

Ridley was interrogated for 10 days without being allowed a phone call, and missed her daughter Daisy's ninth birthday.

Of the Taleban, Ridley says: "I couldn't support what they did or believed in, but they were demonised beyond recognition, because you can't drop bombs on nice people."

It has been suggested the 46-year-old is a victim of Stockholm Syndrome, in which hostages take the side of the hostage-takers.

But she says: "I was horrible to my captors. I spat at them and was rude and refused to eat. It wasn't until I was freed that I became interested in Islam."

'Flappy knickers'

Indeed, the Taleban deputy foreign minister was called in when Ridley refused to take her underwear down from the prison washing line, which was in view of soldier's quarters.

"He said, 'Look, if they see those things they will have impure thoughts'."

"Afghanistan was about to be bombed by the richest country in the world and all they were concerned about was my big, flappy, black knickers.

"I realised the US doesn't have to bomb the Taleban - just fly in a regiment of women waving their underwear and they will all run off."

Once she was back in the UK, Ridley turned to the Koran as part of her attempt to understand her experience.

Abu Hamza
Abu Hamza: warned Ridley risked "hellfire" until she fully converted

"I was absolutely blown away by what I was reading - not one dot or squiggle had been changed in 1,400 years.

"I have joined what I consider to be the biggest and best family in the world. When we stick together we are absolutely invincible."

What do her Church of England parents in County Durham make of her new family?

"Initially the reaction of my family and friends was one of horror, but now they can all see how much happier, healthier and fulfilled I am.

"And my mother is delighted I've stopped drinking."

What does Ridley feel about the place of women in Islam?

"There are oppressed women in Muslim countries, but I can take you up the side streets of Tyneside and show you oppressed women there.

"Oppression is cultural, it is not Islamic. The Koran makes it crystal clear that women are equal."

And her new Muslim dress is empowering, she says.

"How liberating is it to be judged for your mind and not the size of your bust or length of your legs."

Map of Afghanistan
The reporter spent the first night of war in a prison cell in Kabul

A single mother who has been married three times, she says Islam has freed her from worry over her love life.

"I no longer sit and wait by the phone for a man to ring and I haven't been stood up for months.

"I have no man stress. For the first time since my teens I don't have that pressure to have a boyfriend or husband."

But there has been a phone call from at least one male admirer - north London preacher Abu Hamza al-Masri.

"He said, 'Sister Yvonne, welcome to Islam, congratulations'.

"I explained I hadn't yet taken my final vows and he said, 'Don't be pressured or pushed, the whole community is there for you if you need any help, just call one of the sisters.'

'Straight to hellfire'

"I thought, I can't believe it, this is the fire and brimstone cleric from Finsbury Park mosque and he is quite sweet really.

"I was just about to hang up when he said, 'But there is just one thing I want you to remember. Tomorrow, if you have an accident and die, you will go straight to hellfire'.

"I was so scared that I carried a copy of the vows in my purse until my final conversion last June."

And the hardest part of her new life?

"Praying five times a day. And I am still struggling to give up cigarettes."

Posted by the tarakan times at 23:07:40 | Permanent Link | Comments (23) |

Thursday, September 20, 2007

Bin Laden Tape to Declare War on Musharraf

 
Published: September 20, 2007

CAIRO, Egypt (AP) -- Osama bin Laden will release a new message soon declaring war on Pakistani President Gen. Pervez Musharraf, al-Qaida announced Thursday.

The announcement of the upcoming message came as al-Qaida released a new video in which bin Laden's deputy, Ayman al-Zawahri, boasted that the United States was being defeated in Afghanistan, Iraq and other fronts.

Speakers in the video promised more fighting in Afghanistan, North Africa and Sudan's Darfur region.

The messages are part of a stepped-up propaganda campaign by al-Qaida around the anniversary of the Sept. 11, 2001 attacks against the World Trade Center and the Pentagon. Earlier this month, bin Laden released two messages -- including his first new appearance in a video in nearly three years.

A banner posted on an Islamic militant Web site on Thursday advertised that another message would be released, though it did not say whether bin Laden would appear in video or speak in an audiotape.

''Soon, God willing: 'Come to Jihad (holy war)', from sheik Osama bin Laden, God protect him'' the banner read.

''Urgent, al-Qaida declares war on the tyrant Pervez Musharraf and his apostate army, in the words of Osama bin Laden,'' it read.

Such advertisements usually precede the release of the video by one to three days, according to IntelCenter, a U.S. counterterrorism group that monitors militant messages.

The sophisticated 80-minute video released Thursday on the same Web site was in the style of a documentary, intersplicing the speech by al-Zawahri with footage from the Sept. 11 attacks, interviews with experts and officials taken from Western and Arab television stations, and old footage and audiotapes of bin Laden.

Al-Zawahri began by condemning the Pakistani military's July assault on Islamic militants who took over the Red Mosque in Islamabad, and he paid tribute to one of the militants' leaders, Abdul Rashid Ghazi, who was killed in the fighting.

The siege ''revealed the extent of the despicableness, lowliness and treason of Musharraf and his forces, who don't deserve the honor of defending Pakistan, because Pakistan is a Muslim land, whereas the forces of Musharraf are hunting dogs under (President) Bush's crucifix,'' al-Zawahri said.

''Let the Pakistani army know that the killing of Abdul Rashid Ghazi and his male and female students ... has soaked the history of the Pakistan army in shame and despicableness which can only washed away by retaliation,'' he said.

Bin Laden and al-Zawahri are thought to be hiding in the lawless Pakistan-Afghanistan border region, where many analysts believe they have rebuilt al-Qaida's core leadership.

Al-Zawahri called for attacks on French and Spanish interests in North Africa and on U.N. and African peacekeepers expected to deploy in Sudan's wartorn Darfur region.

''What they claim to be the strongest power in the history of mankind is today being defeated in front of the Muslim vanguards of jihad six years after the two raids on New York and Washington,'' al-Zawahri said, speaking in what appeared to be an office, with shelves of religious books and an automatic rifle leaning against them.

''The Crusaders themselves have testified to their defeat in Afghanistan at the hands of the lions of the Taliban,'' he said. ''The Crusaders have testified to their own defeat in Iraq at the hands of the mujahideen, who have taken the battle of Islam to the heart of the Islam world.''

The video included footage of al-Qaida's leader in Afghanistan, Mustafa Abu al-Yazeed, meeting with a senior Taliban commander. In contrast to past videos that showed al-Qaida and Taliban fighters in rough desert terrain, Abu al-Yazeed and the commander were shown sitting in a verdant field surrounded by trees as a jihad anthem played, extolling the virgins that will meet martyrs in paradise.

Abu al-Yazeed said al-Qaida's ties with the Taliban were strengthening. The Taliban commander, Dadullah Mansoor, said: ''We shall target the infidels in Afghanistan and outside Afghanistan: inside all the infidel countries oppressing the Muslims. And we shall focus our attacks, Allah willing, on the coalition forces in Afghanistan.''

Another clip in the video showed Abu Musab Abdulwadood, the leader of Algeria's main Islamic insurgency movement, addressing bin Laden and vowing that ''our swords are unsheathed.''

Al-Zawahri called on supporters in North Africa to ''cleanse the Maghrib (western region) of Islam of the children of France and Spain ... Stand with your sons the mujahideen against the Crusaders and their children.''

The video also included what IntelCenter said appeared to be old, but previously unreleased footage of bin Laden. The images show the terror leader, with a beard streaked with gray and a a white cloth draped over his head, in front of a map showing the Middle East and South and Central Asia. He points to the map with a stick and addresses an unseen audience.

He condemns Arab Gulf governments that have allied themselves with the United States, saying they have ''sold the Islamic nation, colluded with the enemies of Islam and backed the infidels. And this is the greater form of being an infidel ... But Allah permitting, they shall leave the Gulf under the blows of the mujahideen,'' bin Laden said.

Posted by the tarakan times at 19:34:31 | Permanent Link | Comments (0) |

Wednesday, September 19, 2007

Why Am I Not Allowed To Use My Cell Phone In Airplanes?

I've noticed that I am not allowed to use my cell phone in airplanes or in hospitals. Why are these prohibitions in place?

Most of us experience electromagnetic interference on a fairly regular basis. For example:

  • If I put my cell phone down on my desk near the computer, I can hear loud static in my computer's speakers every time the phone and the tower handshake. In the same way, my car's tape player produces loud static whenever I make a call on my cell phone.
  • When I dial a number on my home's wireless phone, I can hear the number being dialed through the baby monitor.
  • It is not uncommon for a truck to go by and have its CB radio overwhelm the FM station I am listening to.
  • Most of us have come across motors that cause radio or TV static.
None of these things, technically, should be happening. For example, a truck's CB radio is not transmitting on the FM radio bands, so my radio should never hear CB signals. However, all transmitters have some tendency to transmit at lower power on harmonic side bands, and this is how the FM radio picks up the CB. The same thing holds true for the wireless phone crossing over to the baby monitor. In the case of the cell phone affecting the computer's speakers, the wire to each speaker is acting like an antenna, and it picks up side bands in the audible range.

These are not dire problems -- they are just a nuisance. But notice how common they are. In an airplane, the same phenomena can cause big trouble.

An airplane contains a number of radios for a variety of tasks. There is a radio that the pilots use to talk to ground control and air traffic control (ATC). There is another radio that the plane uses to disclose its position to ATC computers. There are radar units used for guidance and weather detection, and so on. All of these radios are transmitting and receiving information at specific frequencies. If someone were to turn on a cell phone, the cell phone would transmit with a great deal of power (up to 3 watts). If it happens to create interference that overlaps with radio frequencies the plane is using, then messages between people or computers may be garbled. If one of the wires in the plane has damaged shielding, there is some possibility of the wire picking up the phone's signals just like my computer's speakers do. That could create faulty messages between pieces of equipment within the plane.

Many hospitals have installed wireless networks for equipment networking. For example, look at the picture of the heart monitor in How Emergency Rooms Work. The black antenna sticking out of the top of the monitor connects it back to the nursing station via a wireless network. If you use your cell phone and it creates interference, it can disrupt the transmissions between different pieces of equipment. That is true even if you simply have the cell phone turned on -- the cell phone and tower handshake with each other every couple of minutes, and your phone sends a burst of data during each handshake.

The prohibition on laptops and CD players during takeoff and landing is addressing the same issue, but the concerns here might fall into the category of "better safe than sorry." A poorly shielded laptop could transmit a fair amount of radio energy at its operating frequency, and this could, theoretically, create a problem.

Posted by the tarakan times at 20:00:09 | Permanent Link | Comments (0) |

Tuesday, September 18, 2007

The Abortion Wars Hit Illinois

The Abortion Wars Hit Illinois

Abortion Protest
Anti-abortion protesters
Brendan Hoffman / WPN

In Illinois today, a federal judge is expected to hear an intriguing argument in the abortion debate. At issue: Is Aurora, Ill., a city of nearly 175,000 about an hour's drive west of Chicago, trying to stop Tuesday's scheduled opening of the nation's largest Planned Parenthood clinic because of political pressure from anti-abortion activists? Or was the clinic's true nature — that is, its Planned Parenthood genesis — not readily apparent to city officials when they originally approved permits for the building? Or is it a bit of both? The case is already one of the most heated in the nation's grassroots abortion wars, and protests in Aurora this past weekend drew hundreds of anti-abortion demonstrators.

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The Grassroots Abortion War

Crisis pregnancy centers are fielding an anti-abortion guerrilla army to win over one woman at a time. Are they playing fair?

The story began last winter, when Gemini Office Development LLC applied to build a 22,000-square-foot clinic on land zoned for medical use. The design's details included surgical rooms and various security features, such as bullet-proof glass. Construction proceeded. In July, however, local newspapers reported that Gemini is, in fact, a subsidiary of Planned Parenthood's local branch. Still, in August, the city routinely issued a temporary permit allowing the $7.5 million clinic to open on Sept. 18 with just two relatively minor provisions: install more exit signs, as well as glass at service counters. There seemed to be little legal questions about it at the time: It is normal for commercial concerns to use subsidiaries to conduct business and set up offices.

Of course, Planned Parenthood is not just a company. And abortion opponents in this historically conservative suburb abutting cornfields were outraged. An assortment of groups, including churches, organized around-the-clock protests outside the clinic, which is tucked between a supermarket, a Blockbuster Video, and a cluster of upscale homes. The debate embroiled this city as has few other issues: City council meetings began drawing hundreds of abortion opponents.

And so, amid the outcry over alleged inconsistencies in the application and testimony of Planned Parenthood's executives, Aurora city officials announced on Aug. 30 that the clinic's opening would depend on a fresh review of its building permit. "These concerns were raised once this became high-profile, and people began looking back at the process," says Carie Anne Ergo, the city's spokeswoman. Last Wednesday, the city told Planned Parenthood it "had no intention of allowing you to open for business," according to court documents. On Thursday Sept 13, Planned Parenthood responded with a lawsuit in U.S. District Court attempting to block the city's efforts to stop the clinic's opening, saying it was rooted in discrimination because the clinic would perform abortions.

Shortly after dawn on Saturday, hundreds of abortion opponents arrived at the clinic, which many people on all sides of the debate have started calling "Ground Zero." Some simply prayed on the sidewalk behind the clinic. Many carried signs reading, KEEP ABORTIONS OUT OF AURORA. Cheryl Hartnett, a 52-year-old Aurora retiree, said her "heart broke" when she learned the clinic is owned by Planned Parenthood. "There will be political consequences" for city officials, she warned Saturday, surrounded by a clutch of protesters. Meanwhile, people who live in the homes near the clinic are fearful of potential violence. For much of the weekend, police officers stood guard in front of the entrance to a subdivision behind the clinic.

In an interview, Steve Trombley, CEO of Planned Parenthood's Chicago branch, said his group initially used Gemini to shield the building's contractors and employees from harassment. "I was surprised our opponents didn't figure us out sooner — they monitor our every move," he said Saturday, standing in the clinic's spare, manila-colored lobby. "We answered every question the city asked. This is about political pressure form anti-abortion group," he said of efforts to block the clinic's opening. Abortion opponents say they could recall few cases in which Planned Parenthood used subsidiaries to open clinics. A Planned Parenthood spokeswoman said the use of subsidiaries to open clinics isn't part of a new national strategy, and that "affiliates use different approaches to meet the health care needs of communities."

Last year, Planned Parenthood provided birth control to about 2.5 million patients nationwide. The group says abortions accounted for 3% of its services nationally last year. Elsewhere in the country, abortion opponents have opened so-called crisis pregnancy centers, often next to Planned Parenthood clinics, to persuade women headed for abortions to reconsider the procedure.

In Aurora, abortion opponents promise their protests will continue even as Planned Parenthood says at least a dozen patients have made appointments for Tuesday. Across the city, meanwhile, the clinic seems to dominate conversation. "I'm shocked we're involved in the middle of this," Rick Lawrence, a city alderman, says.

Posted by the tarakan times at 06:25:23 | Permanent Link | Comments (0) |

Monday, September 17, 2007

CNN Interview With Ingrid Mattson

Ingrid Mattson: What is Islam?

October 18, 2001 Posted: 4:03 PM EDT (2003 GMT)

Ingrid Mattson is a professor of Islamic Studies at Hartford Seminary. In 1995, she was an adviser to the Afghan delegation to the United Nations Commission on the Status of Women. The vice president of the Islamic Society of North America, Professor Mattson is a contributor to The Muslim World Journal. She joined the CNN.com chat room from Connecticut.

CNN: Dr. Mattson, could you give us a basic explanation of Islam?

MATTSON: Islam is a global religion practiced by approximately 1.2 billion people in the world. Religious scholars consider it one of the Abrahamic religions meaning that, like Judaism and Christianity, it traces its primary beliefs back to the message of monotheism promoted by the prophet Abraham.

CHAT PARTICIPANT: How do you react to criticism that westerners do not understand Islam?

MATTSON: I don't think that's true of all Westerners, any more than it's true that all Muslims have a misunderstanding of western culture or American life. Unfortunately, there are misunderstandings that often are the result of the limited images of each culture that are shown or promoted in the general media.

CHAT PARTICIPANT: How had bin Laden duped so many Islamic people into believing his war of terrorism is in the name of Allah? The Koran, or at least my interpretation, disallows any killing of innocents, yet many Muslims feel the acts of September 11 were warranted.

MATTSON: I think that not many Muslims, only a small number of Muslims throughout the world would support Osama bin Laden's tactics. A larger number share the grievances that he has voiced, but they would share those grievances if they were voiced by any person. One of the reasons why some poor and marginalized people in the Muslim world have turned to Osama bin Laden as a spokesperson for their grievances, is because they feel that no one else, including their own leaders, has spoken for them.

CHAT PARTICIPANT: Can you give us a view of how many people convert to Islam from other religions, as opposed to Christianity?

MATTSON: I really wouldn't be in a position to give precise figures. What I do know is that according to many scholars, Islam is the fastest-growing religion in the United States.

CHAT PARTICIPANT: Does Islam ever promote violence and, if so, under what circumstances? If not, why do so many Muslims take up arms?

MATTSON: Islam allows force to be used by legitimate authorities, to protect people, and to protect Muslim states, just as all nation states in the world permit themselves to use force to protect their security and interests. Again, the problem of individual Muslims taking up arms, becoming vigilantes, in a way, is related to their frustration with the lack of leadership on the part of their own government.

CHAT PARTICIPANT: What legal rights do women have in Islam? The right to vote, work, own businesses?

MATTSON: Muslim women have the same legal rights as Muslim men. The Prophet Mohammed's wife was a businesswoman. In fact, he met her working for her as her agent. The legal rights of women were enshrined in Islamic law. However, cultural practices in many societies have prevented those rights from being enforced.

CHAT PARTICIPANT: What can you tell us about the Wahhabi sect of Islam? Is it true that this is an extremely right wing sect founded and funded by the Saudi royal family, and led by Osama bin Ladin? What is the purpose of the Wahhabi?

MATTSON: No it's not true to characterized 'Wahhabism' that way. This is not a sect. It is the name of a reform movement that began 200 years ago to rid Islamic societies of cultural practices and rigid interpretation that had acquired over the centuries. It really was analogous to the European protestant reformation. Because the Wahhabi scholars became intergreated into the Saudi state, there has been some difficulty keeping that particular interpretation of religion from being enforced too broadly on the population as a whole. However, the Saudi scholars who are Wahhabi have denounced terrorism and denounced in particular the acts of September 11. Those statements are available publicly.

This quesiton has arisen because last week there were a number of newspaper reports that were dealing with this. They raised the issue of the role of Saudi Arabia and the ideaology there. Frankly, I think in a way it was a reaction to the attempts of many people to look for the roots of terrorism in misguided foreign policy. It's not helpful, I believe, to create another broad category that that becomes the scape goat for terrorism.

CHAT PARTICIPANT: Is there a general feeling among the Muslims that the western world does not take them seriously?

MATTSON: I think that sometimes Muslims feel that their lives, their security, and their right to self-determination are not given very much weight by Western governments. Although, most Muslims would express appreciation for the ability of the average American to react empathetically to their causes.

CNN: Tell us about traditional Islamic dress. Why is it so varied, and so controversial to people of other cultures?

MATTSON: Traditional Islamic dress is modest dress, for men and women. It is considered appropriate public dress, so in the home, Muslims dress much more casually. The controversy arises when governments attempt to enforce a particular religious interpretation of proper Islamic dress on the population at large.

CHAT PARTICIPANT: At what point in history, if known, did the Islamic nation turn from a philosophical and educated state comparable to the Greeks to the now third world state it is in?

MATTSON: Well, the decline began with the colonization of the Muslim world by European powers. One of the first things the colonialists did was to dismantle the institutions of what we could call civil society. The Muslim world has until now not recovered from that dismemberment of its society.

CHAT PARTICIPANT: Jesus said: I am the way, the truth and the Life; no one comes to the Father but by me. What does Islam think of Christ?

MATTSON: It's a principle of faith for Muslims to believe that Jesus was sent by God as a righteous prophet. The Koran states that Jesus was born miraculously of the Virgin Mary, but the Koran states that none of the prophets were divine, including Jesus.

CHAT PARTICIPANT: Does the Taliban place blame upon women for the weakness of men in their society? Is that why they place such restriction upon them?

MATTSON: The Taliban place restrictions on everyone in their society, men and women. They've extended their authority over individuals far beyond traditional government in Afghanistan. In their minds, they are protecting women from other men by placing these restrictions on them.

CHAT PARTICIPANT: What possible justification can there be for the wholesale massacre of civilians in Islam?

MATTSON: There is no justification. It is prohibited in Islamic law. It is a great sin in Islamic theology. This has been stated before and after September 11 by leading Muslim scholars throughout the world. Osama bin Laden and his group are not considered scholars or legitimate interpreters of religion by the vast majority of Muslims in the world.

CHAT PARTICIPANT: Osama bin Laden made a reference that Muslims have been living in humiliation for 80 years. Did he refer to the Treaty of Sevres in 1920 that dismantled caliphates and sultanates?

MATTSON: Yes, he is referring to that, to the overthrowing of the caliphate, which was a plan of European powers for many years. This deprived the Muslim world of a stable and centralized authority, and much of the chaos that we're living in today is the result of that.

CHAT PARTICIPANT: What do you consider to be the best reference work on Islam -- apart from the Koran that is?

MATTSON: If someone wants to have access to a mainstream Muslim perspective, there's a really nice book called "Islam, the Natural Way," and the author is Abdulwahid Hamid. Another book is called "God is One," by Marston Speight.

CNN: Do you have any closing comments for us today?

MATTSON: I'd like to thank everyone for taking time to try to learn about Islam and about Muslims. The only way for all of us to find a way out of this crisis we're in is by understanding the world that we live in. Thank you.

CNN: Thank you!

Dr. Ingrid Mattson joined the chat room via telephone from Connecticut and CNN.com provided a typist. The above is an edited transcript of the interview on Thursday, October 18, 2001 at 11:30 a.m. EDT.


 

Posted by the tarakan times at 07:03:39 | Permanent Link | Comments (0) |

Saturday, September 15, 2007

How Earthquakes Work

How Earthquakes Work 

Inside This Article
An earthquake is one of the most terrifying phenomena that nature can dish up. We generally think of the ground we stand on as "rock-solid" and completely stable. An earthquake can shatter that perception instantly, and often with extreme violence.  Up until relatively recently, scientists only had unsubstantiated guesses as to what actually caused earthquakes. Even today there is still a certain amount of mystery surrounding them, but scientists have a much clearer understanding.

Earthquake Image Gallery

 

A section of Interstate 880 in Oakland, Calif., damaged by a magnitude 7.1 earthquake
Photo courtesy USGS
A section of Interstate 880 in Oakland, California, damaged by the magnitude 7.1 earthquake that shook the
San Francisco area in 1989. See more earthquake pictures.

There has been enormous progress in the past century: Scientists have identified the forces that cause earthquakes, and developed technology that can tell us an earthquake's magnitude and origin. The next hurdle is to find a way of predicting earthquakes, so they don't catch people by surprise.  In this article, we'll find out what causes earthquakes, and we'll also find out why they can have such a devastating effect on us.

 

 

 

­

Shaking Ground
An earthquake is a vibration that travels through the earth's crust. Technically, a large truck that rumbles down the street is causing a mini-earthquake, if you feel your house shaking as it goes by, but we tend to think of earthquakes as events that affect a fairly large area, such as an entire city. All kinds of things can cause earthquakes:
  • volcanic eruptions
  • meteor impacts
  • underground explosions (an underground nuclear test, for example)
  • collapsing structures (such as a collapsing mine)
But the majority of naturally-occurring earthquakes are caused by movements of the earth's plates, as we'll see in the next section.

We only hear about earthquakes in the news every once in a while, but they are actually an everyday occurrence on our planet. According to the United States Geological Survey, more than three million earthquakes occur every year. That's about 8,000 a day, or one every 11 seconds!

 

 

residential damage caused by an earthquake
Photo courtesy FEMA
Residential damage caused by the 1994 earthquake in Northridge, California.

The vast majority of these 3 million quakes are extremely weak. The law of probability also causes a good number of stronger quakes to happen in uninhabited places where no one feels them. It is the big quakes that occur in highly populated areas that get our attention.

Earthquakes have caused a great deal of property damage over the years, and they have claimed many lives. In the last hundred years alone, there have been more than 1.5 million earthquake-related fatalities. Usually, it's not the shaking ground itself that claims lives -- it's the associated destruction of manmade structures and the instigation of other natural disasters, such as tsunamis, avalanches and landslides.

 

residential earthquake damage in Prince William Sound, Alaska
Photo courtesy NGDC
Residential damage in Prince William Sound, Alaska, due to liquefaction caused by a 1964 9.2-magnitude earthquake.

In the next section, we'll examine the powerful forces that cause this intense trembling and find out why earthquakes occur much more often in certain regions.

Sliding Plates

the San Andreas fault
Photo courtesy USGS
One of the best known faults is the San Andreas fault in California. The fault, which marks the plate boundary between the Pacific oceanic plate and the North American continental plate, extends over 650 miles (1,050 km) of land.
The biggest scientific breakthrough in the history of seismology -- the study of earthquakes -- came in the middle of the 20th century, with the development of the theory of plate tectonics. Scientists proposed the idea of plate tectonics to explain a number of peculiar phenomenon on earth, such as the apparent movement of continents over time, the clustering of volcanic activity in certain areas and the presence of huge ridges at the bottom of the ocean.

The basic theory is that the surface layer of the earth -- the lithosphere -- is comprised of many plates that slide over the lubricating athenosphere layer. At the boundaries between these huge plates of soil and rock, three different things can happen:

  • Plates can move apart - If two plates are moving apart from each other, hot, molten rock flows up from the layers of mantle below the lithosphere. This magma comes out on the surface (mostly at the bottom of the ocean), where it is called lava. As the lava cools, it hardens to form new lithosphere material, filling in the gap. This is called a divergent plate boundary.

     

  • Plates can push together - If the two plates are moving toward each other, one plate typically pushes under the other one. This subducting plate sinks into the lower mantle layers, where it melts. At some boundaries where two plates meet, neither plate is in a position to subduct under the other, so they both push against each other to form mountains. The lines where plates push toward each other are called convergent plate boundaries.

     

  • Plates slide against each other - At other boundaries, plates simply slide by each other -- one moves north and one moves south, for example. While the plates don't drift directly into each other at these transform boundaries, they are pushed tightly together. A great deal of tension builds at the boundary.

Click here for a great plate-boundary diagram.

Where these plates meet, you'll find faults -- breaks in the earth's crust where the blocks of rock on each side are moving in different directions. Earthquakes are much more common along fault lines than they are anywhere else on the planet.

In the next section, we'll look at some different types of faults and see how their movement creates earthquakes.

Faults

Scientists identify four types of faults, characterized by the position of the fault plane, the break in the rock and the movement of the two rock blocks:
  • In a normal fault (see animation below), the fault plane is nearly vertical. The hanging wall, the block of rock positioned above the plane, pushes down across the footwall, which is the block of rock below the plane. The footwall, in turn, pushes up against the hanging wall. These faults occur where the crust is being pulled apart, due to the pull of a divergent plate boundary.

 


Normal fault

 

  • The fault plane in a reverse fault is also nearly vertical, but the hanging wall pushes up and the footwall pushes down. This sort of fault forms where a plate is being compressed.
  • A thrust fault moves the same way as a reverse fault, but the fault line is nearly horizontal. In these faults, which are also caused by compression, the rock of the hanging wall is actually pushed up on top of the footwall. This is the sort of fault that occurs in a converging plate boundary.

 


Reverse fault

 

  • In a strike-slip fault, the blocks of rock move in opposite horizontal directions. These faults form when the crust pieces are sliding against each other, as in a transform plate boundary

 


Strike-slip fault

In all of these types of faults, the different blocks of rock push very tightly together, creating a good deal of friction as they move. If this friction level is high enough, the two blocks become locked -- the friction keeps them from sliding against each other. When this happens, the forces in the plates continue to push the rock, increasing the pressure applied at the fault.

If the pressure increases to a high enough level, then it will overcome the force of the friction, and the blocks will suddenly snap forward. To put it another way, as the tectonic forces push on the "locked" blocks, potential energy builds. When the plates are finally moved, this built-up energy becomes kinetic. Some fault shifts create visible changes at the earth's surface, but other shifts occur in rock well under the surface, and so don't create a surface rupture.

 

offset crop rows due to a lateral strike slip fault earthquake in Guatamala
Photo courtesy USGS
Crop rows offset by a lateral strike slip fault shifting in the 1976 earthquake that shook El Progresso, Guatemala.

The initial break that creates a fault, along with these sudden, intense shifts along already formed faults, are the main sources of earthquakes. Most earthquakes occur around plate boundaries, because this is where the strain from the plate movements is felt most intensely, creating fault zones, groups of interconnected faults. In a fault zone, the release of kinetic energy at one fault may increase the stress -- the potential energy -- in a nearby fault, leading to other earthquakes. This is one of the reasons that several earthquakes may occur in an area in a short period of time.

 

shifted railroad tracks due to the earthquake in Guatamala
Photo courtesy USGS
Railroad tracks shifted by the 1976 Guatemala earthquake

Every now and then, earthquakes do occur in the middle of plates. In fact, one of the most powerful series of earthquakes ever recorded in the United States occurred in the middle of the North American continental plate. These earthquakes, which shook several states in 1811 and 1812, originated in Missouri. In the 1970s, scientists found the likely source of this earthquake: a 600-million-year-old fault zone buried under many layers of rock.

The vibrations of one earthquake in this series were so powerful that they actually rang church bells as far away as Boston! In the next section, we'll examine earthquake vibrations and see how they travel through the ground.

 

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