tonight on "nightline," quaketown, usa. earthquakes, dozens a day, shaking small towns where big energy companies are drilling for gas. now, residents are up in arms. are earthquakes the price to pay for drilling in our back yards? plus, lawsuit barbie. she's the most popular doll ever. barbie. hit today with a multimillion dollar judgment, after a playground showdown with competitor bratz. we go behind the scenes of the billion dollar doll wars. and, real lion king. one lioness, one cheetah, two big feline moms raising cubs in

the wild of kenya, in the face of grave danger. these filmmakers get incredibly close. >> announcer: from the global resources of abc news, with terry moran, cynthia mcfadden and bill weir in new york city, this is "nightline," april 21st, 2011. >> good evening. we begin tonight with energy policy. today, a natural gas company halted its use of a controversial mining technique call eed fracking, after a blowt spewed thousands eed fluid int. in arkansas, some geologists think the disposal of waste water from fracking may be leading in an uptick of earthquakes, more than 1100 since september. here's chris bury.

>> reporter: at this arkansas school, anger is in the air. >> you need to start hounding your government. >> reporter: the residents gathered here are worried. >> how would we know? >> reporter: about the gas wells sprouting up around them. >> i just know my house started shaking. >> reporter: and whether drilling is to blame for the earth moving under their feet. >> the house shoot, all the dogs started barking and going off. something happened. >> reporter: what's happening? earthquakes. more than 1100 since september. most of them tiny, two or three on the richter scale. but some around four, california-sized. teachers at this school attest to that. >> there's no foundation. you're just shaking. and you can't go anywhere because every is shaking. >> that scared me the most, was, in the middle of doing a lesson with my students and the earth shaking and realizing it was an earthquake. >> reporter: the shaking here is the newest development in the

raging national argument about drilling for natural gas. >> what's happening, how are they happening, why are they happening, we know that they're happening. >> reporter: josh fox, a filmmaker, is here showing his oscar nominated dock yultry, "gasland." >> i would love to find somebody to interview at halliburton. >> reporter: his film is critical of fracking. fluid is injected into rock, breaking it to release gas. the film focuses on fears about the water supply. >> whoa! jesus christ. >> reporter: "nightline" brought fox to arkansas because of all the new questions here about drilling and earthquakes. the voices here, he says, are like canaries in a coal mine. >> people are your first level of scientific data. you have to trust what people are saying on the ground as your first level of any investigation. >> reporter: in the gentle hills of the arkansas river valley, the treasured serenity has been

shattered. >> the ground just romlls. >> reporter: for dirk and his neighbors, the shaking began last summer. >> and it's like a loud thunder clap and the house shakes at the exact same time. >> this has split and cracked here in the sheet rock. >> reporter: it seems like your house is kind of separating. >> yes, my whole house is kind of -- that's a good way to put it. >> reporter: susan showed us the cracked walls in her home. >> this house was swaying. you felt like you were on a roller coaster, going down a hill or sitting on a row boat in the middle of the ocean with somebody rocking the boat. >> reporter: the shaking got so frequent, he installed a plum line to keep track, posting the results on youtube. >> 4:54 p.m. and we got some really big swaying going on now. >> about 1,050 earthquakes. >> reporter: scott orbrooks is a lead detective on the case.

these dots represent the earthquakes that have occurred since last summer? >> yes, sir. just since, basically, since september. >> reporter: the earthquakes are rattling the countryside in what's known as the fayetteville shale. just since 2005, more than 3,000 gas wells have been drilled here, bringing thousands of jobs and billions in revenue to a dirt poor place. but at what cost? >> it's continuing to produce more and more waste. >> reporter: josh fox is exploring a theory held by many residents that the tremors can be traced to how waste water is handled. >> you see that enormous pit of waste water there? >> reporter: right. >> that's waste water, coming up out of the well and this is what they are injekting back into the ground. >> reporter: the waste water, millions of gallons, is trucked to disposal sites like this. they inject the equivalent of a 30-acre lake, weighing 1 billion

pounds, deep into the earth. but the gas companies insist, no scientific evidence links the injection womens to earthquakes. and that some quakes were recorded in the region before the wells were drilled. >> i never been so scared in my life. >> reporter: but nothing like this. >> it just rattled the foundation. >> reporter: in february, a 4.7 shook the earth all the way to memphis, the biggest quake here in 35 years. >> all of a sudden, the whole bed just was like that, the whole house, you could just feel everything. everything going. >> reporter: geologists hunting clues to the history are installing seismic monitors across the region. >> kind of like earthquake chasing. >> reporter: now they're getting real-time data from state parks to backyards. the quakes are taking place along a newly discovered fault line, 7 1/2 miles long. >> if that was to rupture at one people, we could generate up to a magnitude 5.7 to a 6.0.

>> reporter: which is a really big -- >> which is a damaging -- could be a very damaging earthquake. >> reporter: in march, only days after that 4.7 earthquake, energy companies under pressure from state regulators shut down two injection wells closest to the fault line, including this one, then owned by chesapeake energy. >> we do not agree with the conclusions. we believe there's a lot of natural size misty in this area. and there's a lot more sub-surface data and facts and science that needs to be brought to bear. >> we have to to side with the public safety concern and address that in a way that maybe science does not totally supp t support. >> reporter: if there is a tie, you have to come down on the side of the residents? >> yes, we think public safety has to rule the day. >> reporter: since the two injection womens have shut down, the earthquakes have not stopped, but they have tapered

much that mdramatically. >> 50% reduction. >> reporter: pretty dramatic. arkansas has now put a temporary halt on any new disposal wells, and for some here, the evidence is piling up. are you convinced that this drilling is leading to the earthquakes? >> yes, i am. i am 100% totally convinced. >> reporter: kwincoincidence or, arkansas legislators may decide soon if they let the wells operate again, leaving residents to think if peace will ever return to their valley. i'm chris bury for "nightline" in guy, arkansas. >> our thanks to chris for that important report. many questions still to be answered. just ahead, from the dollhouse to the courthouse. how did barbie fare in a legal battle against the new doll on the block? we have the story.

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>> announcer: "nightline" continues from new york city with cynthia mcfadden. >> and now, to the law, well, she's been around since 1959. so, she's officially middle aged, but there's no sign that her popularity is waning. in fact, sales of barbie dolls are up 14% this year. that, despite the fact that barbie has stiff competition for the hearts of little girls the world over, including from a plucky young lass called bratz, who scored a big win in court today. here's david wright in los angeles. >> reporter: she's the sassy new kid who took on the popular girl. in a toy story courtroom saga that's dragged on seven years. >> barbie and her pay master matel, between the two of them,

are verily tigss. bratz would have been happy to just go about its business, but matel, the toy giant, came along and, you know, had other ideas. >> reporter: but today, bratz got her payday, at barbie's expense. i think it's a huge deal. it looked like an easy victory for mattel, but the case has taken a bunch of twists and turns. >> reporter: mattel has long maintained that the creator of bratz stole the idea from them. the doll's designer used to work for them. >> i think any industry that has invention and innovation at its core is going to be incredibly protective and secretive. >> reporter: in 2008, a california jury ruled in mattel's favor, awarding barbie $100 million. >> it was a giant court battle over a little girl's doll but about a big business. >> reporter: last summer, the 9th circuit court of appeals stood up for the girls with a passion for fashion, ruling that

the queen of the doll market could not just chop off the heads of any pretenders to the throne. the judge ordered that barbie is relatively demure where as bratz are urban, multiethnic and trendy. dolls with attitude. in other words, the two products are plenty different. he ruled, quote, america thrives on competition. barbie, the all-american girl, will, too. >> reporte so, bratz got a retry. this time, a jury of her peers cited with her. now barbie has to pay bratz nearly $89 million in damages and there could be punitive damages, too. >> all the way for the money, i think was the principle of it. >> reporter: what is the principle? >> the principle is that, being multinational company in this country cannot come and basically bully and steal small entrepreneurs and get away with this. if we lost this, our whole company would have been lost out.

>> reporter: barbie must be crest fallen, but shell's a classy girl, and mattel was gracious in defeat. we are disappointed by the veeshgt, the company said in a statement, adding, mattel's first priority is, and always has been, to make and sell the best toys in the world. >> part of what was at stake in this case and through its long history was, what do you make of a situation in which an employee might have gotten an idea and initial inspiration from working with barbie? and then strikes out on his own and does all of the work or nearly all of the work on his own? >> reporter: who are these? >> that's a barbie. that's a bratz. >> reporter: the verdict that matters the most -- do you know that these dolls have been fighting? the people that own these dolls have been having a big fight in court. and now barbie has to pay bratz a lot of money. do you know how much?

guess? >> um -- $25,000. >> reporter: more. >> really? >> reporter: the sisters were sympathetic to barbie. >> i feel bad for barbie, i guess i'd feel bad for her. >> reporter: and what about you? you feel bad for barbie? >> well, sort of, because she has, like, 8,000 million gazillion dollars and she only has to pay -- to her, that's just $5, maybe. >> reporter: right. $84 million is a drop in the bucket for barbie. >> yeah. >> reporter: but they are well aware barbie can afford it. now, crucial question. which one do you like best? >> barbie. >> reporter: you? >> barbie. >> reporter: unanimous. barbie doesn't just have all those careers to fall back on. she has all those girls. win or lose in the rough and tumble valley of the dolls, barbie will be just fine.

i'm david wright for "nightline" in los angeles. >> i had that barbie doll. and you thought dolls were just toys. next up, a pair of big cats caught in a game of survival and captured in one incredible film. [ male announcer ] is zero worth nothing? ♪ imagine zero pollutants in our environment. or zero dependency on foreign oil. ♪ this is why we at nissan built a car inspired by zero. because zero is worth everything. the zero gas, 100% electric nissan leaf. innovation for the planet. innovation for all. i feel like i have to wind myself up to deal with the sadness, the loss of interest, the lack of energy. [ male announcer ] ask your doctor about pristiq®, a prescription medicine proven to treat depression. pristiq is thought to work by affecting the levels of two chemicals in the brain,

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from bambi to dumbo, some of most best loved animal stories follow a mother's love in a hostile world the best tales often rely on real life stories, as captured by an extraordinary new film about two feline moms. vicki mabrey met with the makers of "african cats" for our series "into the wild." >> reporter: a mother's instinct is to protect her babies, and so

it is with this cheetah mother with five newborn cubs. >> she has to get by on her own, come what may and those cubs are completely dependent upon her. >> reporter: and a lioness with a 6-month-old cub. >> she's within a pride. you think that's got to be better. but in a pride, you have politics and you are either in the game or you are out of the game. you see two very different stories. but it's about two months, basically, they've got the same problem. they've got to raise those cubs. >> reporter: they are the stars of disney nature's "african cats," filmed in kenya. two years they followed the big cats, documenting their ferocious love, their life and death struggles. the crew's access, the proximity, was remarkable. >> we were so close.

and they could easily just take a paw and say, have some lunch. but they don't. it's very interesting. if you step out of the vehicle, they would probably go for you straight away. >> reporter: we metal li the tw who admitted they casted the cats with "the lion king" in mind. >> we wanted to make the real "lion king." that's the boy there having a roar. >> i think -- >> amazing sound. >> he's just recognized allistair as a rival. >> reporter: the film is theatrical, with heroes, plot lines and story arcs. filled with drama and comedy and tragedy. >> the oldest lioness was limping. she had a 6-month-old. we knew to bring up that cub was

going to be a real struggle. she does at the end make it and in the end is reunited as a grown-up. it's a disney film. it has to have a happy ending. >> reporter: this is vicki mabrey for "nightline" in new york. >> beautiful. "african cats" opens tomorrow, earth day. disney, our parent company, is contribu trigtributing to the a wildlife foundation. finally tonight, senator john ensign of nevada announced today that he is resigning, elected to the senate as a family values conservative. in 2007, he began an affair with the wife of his best friend and top staffer doug hampton. he gave an exclusive interview to "nightline" two years ago, charging that ensign had broken senate rules and the law when his parents paid the hamptons $96,000. that payment has beennd