welcome to the science for the public lecture series the science for the public is an organization committed to bringing science information and issues to the general public this is our website for our program  chair department of earth and environmental sciences at boston college and also director of boston colleges weston observatory dr abel received his ph d in jail physics from california institute of technology in one nine hundred eighty one enjoying the faculty of the boston college in the same year since that time he's been charge of the new england seismic network of western observatory at boston college network of seismic stations for the six new england states dr evil's research focuses primarily earthquake patterns in new england and vicinity although he's also published papers on earthquake activity in other parts of the united states and other nations he's also conducted extensive research on methods for earthquake hazard computation and earthquake forecasting he's been a consultant on seismic hazard and nuclear test ban treaty monitoring issues for the government agencies including arc on national laboratory the u s nuclear regulatory commission and lawrence livermore national laboratory he's been a consultant on seismic hazard for over twenty major engineering projects in the u s and other countries and he served on national research council panels on studies concerning seismic hazard and low level radioactive waste siting he's received distinguished a wards for his research service for additional information please check tonight's event page on  website and now we're very pleased to welcome dr john evolve welcome dr evil thank you very much and i'll ask to start with if you could please give us a little background on tectonic plates the seem to be the basis of everything what i say the earth is a solid body but the interior of the earth the rock moves just a little but it flows very very slowly except for the very very outer shell about sixty miles from the surface and down into the earth is quite rigid and so the outermost part moves as a rigid set of rigid blocks and blocks move some move away from each other as we have spreading at the middle of the atlantic ridge mid atlantic ridge and other spreading centers there are places where one plate comes against another plate slides back into the earth and then there are places where one plate slides against another instance happens at the san andreas fault i see so it's not all the same kind of movement it's all dynamic but it's some of them are sort of overlapping and some of their sliding against each other  are different plate interactions in different places and that gives slight differences in the way the earthquake was evidently it's a little different in the pacific for example than in the city growing a fire area as opposed to the atlantic ridge is that the case where we don't seem to have these huge wings iceland for example has spreading earthquake or as sumatra has subduction zone great point so very different very different in terms of the sizes  somewhat different in terms of the effects all i see i see ok when you have an earthquake what's happening to a seismologist like myself there are actually two different aspects ok to an earthquake all right earthquake is caused because the rock is being squeezed much more strongly in one direction than another it's kind of like putting a clay brick in a vise crank the vise crank the vise increase the pressure increase the pressure crease the pressure rock is like brick it won't withstand the pressure forever at some point the rock cracks yeah and it slides to release they have pressure to equalize the pressure ok so when it cracks that crack has a name we call it a fault and when it slides the sliding creates vibrational waves just as if you were to slide a heavy piece of furniture across the floor ok you feel vibrational waves those waves spread out just as for instance if you were to have a clear lake on a very still yeah running right across a pebble in right you could see those waves go for hundreds and hundreds and hundreds of yards if you watch same thing happens in an earthquake so if you're near an earthquake epicenter yeah the shaking is very strong if you will be farther away the shaking is weaker if you're farther we still the shaking is weaker ok that's good to go then and then a lot of earthquakes occur in the oceans right is tsunami earthquakes as i said cause or cause the rock to crack the rock slides on the fault and cracks now if you have a water body above where the earthquake takes place and the ocean floor is either shifted up or shifted down yeah it will like if you think you think of a children's plastic swimming pool put your hand underneath this one pool suddenly push up the bottom high the water has to readjust yeah it's a wave moves away from where your was exactly the same thing happened when you have the fall thing that moves the ocean floor up or down there then cause the water to readjust it sounds a wave out and that wave causes water to for instance push up to the it's really like this flood that just keeps coming and coming and coming and coming and it takes about fifteen or twenty minutes for the the tsunami phenomenon itself to come on shore it's put someplace that can be as much as thirty minute ride on the grounds on shore well then the way once it's reached its maximum extent then it drains away but tsunamis oftentimes have multiple waves have one wave come and then a half hour later another wave come an hour and a half later on a very much time and you can have these oscillations yes for four six eight ten twelve hours depending upon how the waters dispersed across the ocean basin i see usually the first wave or two is the worst but you know once you have area yeah you know if you have buildings and they're getting hit by wave after wave after wave maybe an earlier wave damages the building and  later wave than takes the building the tsunami has some peculiar features right so in terms of kind of comparing it with wave waves ordinary waves in the ocean or r that are huge that spring up out of nowhere there are some features about the tsunami that is that are quite different the speed to the wave itself of course it moves with a certain speed but the up speed depends upon the depth of the ocean water or the wave is so where the ocean is very deep the water in the wave spreads out so the way if only has a very small what we call amplitude only has a very small height i say you know so in it when the japan earthquake occurred there was a big tsunami associated with it yes in the open ocean the tsunami was only about six to nine inches and go right over here but it was spread over hundreds of miles yes i say and it was moving very fast it was moving at several hundred miles per hour yes as the where water comes up the shore the water depth becomes shallower yeah the wave slows down so instead of having a small amplitude spread over a wide area what you have is now a slower moving wave where the wave is spread over a smaller area and it has a higher amplitude so you know this this six inch is in the open ocean right now piles up to thirty feet by the time it gets to the shoreline and that's what inundates ok so it's very fast is it true that it's as fast as a jet water's coming in a twenty five to thirty miles per hour and that's one of the reasons why you have so much loss of life ok exactly now is the trick here is that it just keeps rolling because it's all backed up this is this is this huge it's not a single wave right it's multiple it's a group of way where you have one large wave the way and then as it goes out the next wave is  in now you know the time between waves can be at half or an hour and in fact sometimes tsunamis and this is a real problem in some areas that tsunami actually starts with a withdrawal it starts with a likes to pull of the ocean so you'll have the ocean pull out over ten or fifteen minutes and that movement is fast enough that it can for instance strand fish on a beach is that that something and so you have some places where there have been deaths because the water withdraws right people say hey there's that's no good you know they're looking good there they go running out the water comes back and it comes in faster than that and run and then they get inundated so that's that's that's it's quite amazing that you'd have that kind of a phenomena which is a little different from i guess normal kinds of waves is that something that we normally don't associate with you know the way water wave exactly so now normal waves are also surface correct they're not coming from the bottom of the ocean up is that correct the the tsunami waves yeah are travelling horizontally i mean if you were right if you had the right above the earthquake yeah there would actually be a component there would be going up yeah but as soon as you get a few miles away from here it's just a way that i like it but it's fast it's fast and it's travelling horizontal and then could before we believe that can you distinguish that from a rogue wave that these are terrifying to ships in the sea apparently it didn't is there anything there's no relationship between the earthquake and that i'm sure but but right rogue waves are very high are all tsunamis are not necessarily high when they get into the beach right especially after the first that's right yeah if you're out in deeper water you barely notice it's right you know the ships are safe they don't have a problem there i have a problem if they're close to shore and the water pushes the onto the shore ok rogue waves that happen in storms for example are happen when the ocean is choppy and you happen to get just a proper constructive interference of different planes they give me very very tall column of water but you know out of the blue if you're you know if you were in a ship and a roadway were to hit you you would have been going up and down like this as if you were in a ship let's say a mile off shore of a tsunami you barely notice the then the earthquakes that cause tsunamis are in the ocean right there they're land earthquakes that can cause a tsunami if you have an earthquake the land almost all of the displacement is on the land itself so any movement in the water is so minor if it's never damaging you know with very sensitive instruments we might sense a very slight water vibration a change but for all practical purposes it it doesn't mean anything ok how about these huge there was say landslides or whatever like we were talking about the canary island situation what about that they say that you couldn't cause make a tsunami is that possible there were there was what is that there were some calculations that some scientists had done that said if you had a major volcano i mean you have to be moving literally cubic miles of rock and that were to happen all at once yes they did a calculation that suggested that there could be a big wave that would move across the ocean it could be damaging far away it's more recent calculations have actually disputed they're good good good to know that on the other hand there we do know that locally in  there have been landslides for instance in one nine hundred fifty seven there was a large earthquake in alaska it caused a landslide in an enclosed a bay there were two ships that were anchored in the bay the night of the earthquake and they got report of the people on the ship they were holding up to the side of the ship they were looking down in the water they could see the tops of the trees isn't that something in the water under the boat and they end up being deposited out in the ocean million lives were lost hundreds of thousands of rai they didn't seem to expect that at all why is that a region not associated with earthquakes or they didn't have equipment  to detect them why would they not have any expectation that this was coming i think it's i think it's a stretch to say that there was no expectation because in fact two years before that earthquake there had been a conference all held all about the possibility of two nominees in the indian ocean and scientists had gone along the shorelines of sumatra and some of the other islands and they and they have met tsunami deposits and knew that there had been so big there the problem was they had never had evidence of a major tsunami that had gone across the ocean basin to for instance india or for instance to the african coast and people had because there was no record of their scientists had looked for tsunami deposits in those areas and it's kind of the way we human beings do think oh you know if if never happened we don't think it can happen yeah and you know a scientist like myself can might come and say well it might be possible and people say well if we've never seen it we're not going to go look for something we have ever seen right and so now we know that it can happen now there is a tsunami warning system for the for the indian ocean as well as for the atlantic now there's actually one for the pacific for i'm sorry there's a warning for the indian ocean in the pacific but we also saw up a warning system for the atlantic because there have been tsunamis for instance in in puerto rico and the virgin islands and places like there and there's a consideration could we have a tsunami along the atlantic coast even here in new england that yeah  your idea that's your my opinion is yes we could could you go into that because i thought we never had anything you know on the northeast atlantic but your work has indicated crime any we get these little earthquakes nine there was a an earthquake of magnitude seven point three that was centered just south of newfoundland the grand banks you have that you kind of have the land in one area and then the landslips of it's covered with water and you have the continental shelf so the water's now very deep it might be fifty one hundred feet deep but it's not deep ocean and then the ocean floor drops off to the deep ocean and that's where you get then the what we call the  and it caused strong shaking in newfoundland in nova scotia it was felt in boston it was felt in new york city not very strongly but well that night eight  tsunami with waterways higher than ten came onshore in southern newfoundland and actually devastated some villages they had people literally killed in this tsunami now there are one hundred twenty nine we already had telephone between north america and europe and there were a number of telephone cables that went along the ocean floor well the earthquake apparently triggered a submarine slump so sediments there were on the bottom of the ocean on the slo down to the deep ocean actually slumped down and broke these telephone cable oh my goodness and then probably contributed to helping cause the tsunami but they had ten to twenty foot waves come on shore in southern newfoundland with smaller waves detected for instance along the nova scotia coast ok so so that's up in newfoundland so you save canet half the here for instance in the along the new england coast man chooses rhode island  connecticut city you hear well in two thousand and twelve we detected an earthquake offshore east of boston right again at the edge of where the continental period ironically two days later there was an earthquake up at the grand banks of newfoundland also same kind of setting so i in the students study that particular earthquake swarm and except for the fact that the earthquake so much smaller it looks very similar to what happened up at the grand banks i see so what i tell people is any place we have smaller earthquakes we have the potential for a larger earthquake so in my opinion we the shelf is not that far off shore is it no you're talking about oh maybe one hundred miles to where these are of course occurred right and that's a sharp drop isn't it or is relative ok i mean down but you know it it would be comparable to write a very good slope in any case there would be that possibility that you could have a very strong earthquake in fact and that you know you could even have  talking about an hour a few hours later yeah ok you know even even in the case of japan you had the bigger earthquake yeah it took the water fifteen or twenty minutes to go from where the earthquake was  and well that's nice them cheer us right up ahead so today you have spectacular equipment i think and could you tell us what  do how you evaluate these signals and your the western observatory and so on can you give us some background absolutely so today even though we still run at western observatory the drum that go along yes see the pen and watch the line right in fact the way we really want to record is on a computer because then we can do sophisticated computer and alice's of the i say and then the other thing that's wonderful is the internet because it allows us to transmit seismic data from anyplace to anyplace else so western observatory receives seismic data from seismic stations scattered throughout new england we now cooperate with our colleagues in canada they send us seismic data from their seismic stations we can see seismic data from other parts of the world for instance if i wanted to i could get a  seismogram from bermuda of our local earthquakes so all of those data now are being sent by the internet to western observatories being received costly twenty four hours a day seven days a week and we have several computers that are receiving the data and then we have computer programs that are constantly analyzing the data and looking to see you know what it recorded is there something that could be an earthquake and now we have computer programs that if it thinks that there is an earthquake signal on one make station a chick's the other side and if it gets a signal on several seismic stations as all this looks like an earthquake then it says ok well let's put all of those data together and though it's tried to get an automated location and estimate automatically of the magnitude and so within five minutes of an earthquake happening and our region then the computer says ok i have a location i have a magnitude it's pass all of our tests for being real we're going to send out a text page so i get a text page i get e mail my colleagues at western observatory get this information so within say five or seven minutes may i say when the earthquake i have an idea that an done here i'm going to go you're going to go do that right exactly like how long have you had that kind of capability where it seems instantaneous there are two themes of having really good quickly and secondly that you can communicate all over the place very quickly is this fairly new it's i would say fifteen years old yeah you know as the internet you know the internet started in the one nine hundred ninety s and as it grew up during the turn of the twenty first century you know the internet became faster and we started pumping more data to the internet we started writing computer programs that did these automated locations and and to get an automated magnitudes and they became more sophisticated with time but it's really been since about the year two thousand that this capability has been pretty widespread and hey it gets better all the time  not only do i get eve mails from my system but the canadian send me e mails as you would ask what i mean your day sunny pastels and so you know i within ten minutes only yeah there is an earthquake it's over there ok right but i imagine that it's very enough here i will get text pages from the u s geological survey with the magnitude and the location and i will i will get locations from my local seismic stations because that when they get the waves they'll also do a location and they will send it is it's amazing let me ask you if it in the remember in that horrible thing in the indian ocean there are monitoring devices in the oceans are so so what they do is places where they know that tsunamis are frequent and can be triggered they have booties that have basically pressure sensors and the height of the water for the water gets high it's a little excess pressure and it sends that to a satellite but those are put in a few strategically say so that after the earthquake they will know when the tsunami is and they'll have some idea about how big it you have done work for on a train a nuclear activity as well tell us about that what's the difference between that kind of seismic activity and earthquakes can you distinguish it easily  we can distinguish it but i wouldn't necessarily say easily when nuclear testing went underground in one thousand nine hundred sixty two it was realized that the primary way we were going to be able to monitor the nuclear test ban treaty was by using sensors that would detect seismic waves because an underground nuclear explosion would send out seismic waves think and we had some idea about what differences there should be but we needed to document that so starting in the one nine hundred sixty s there there was a very large field of nuclear test ban treaty research and i think and studying earthquake signals studying explosion signals from nuclear tests studying explosions signals from not nuclear tests because you know just because you see an explosion doesn't mean that it's a nuclear explosion so we've been working and when i say we i'm talking about the entire seismology communities but working for many years to distinguish these we now have a good idea about when we have an explosion as opposed to when we have an earthquake my system at west observatory is one that if it thinks it's got a core a blast or some sort of miami to get closure and it doesn't send me a text pa i think this is an explosion not an earthquake sometimes it's wrong but most of the thai right now then the next question is when there's an explosion is it a chemical explosion earth is it a nuclear explosion and that's cutting to finer details and that's a harder problem and it's not completely solved even though the politicians want to be able to say with one hundred percent certainty this is a nuclear explosion this is another nuclear that lotion and i would say we're probably ninety five or ninety seven percent there i would have thought a nuclear would be substantially greater then let's say something from the mines or an underground explosion of some sort i guess volcanoes would be large explosion might be a lot cheaper than it is to drill one little pull the right so you have that and then what countries have become more sophisticated and over tie is reducing the size of their nuclear explosive because they're not trying to test the whole bomb they're actually just trying to test little pieces of the bomb they want to know will the trigger words will they start the ignition of the nuclear  the nuclear reaction because once they start they know they can keep it going i say so so they so they're oftentimes just checking the triggers they're testing to see does this start the process the way we want and that's not a large explosion so so you could have a lot of overlap between the size i see i see i didn't realize that i thought they had to drop the well or put them you would deep in the ground or something will that is quite interesting but now you've got this pretty refined i guess great deal of of research that's done on that and of course some of the research is classified so i i'm not i don't have privy to it and if i did i could tell you about iraq in terms of your work you do a number of these things you're busy man but in terms of this work was there a reason to settle on the east coast though that the east at last test in particular that was there in we're not aware of having so much activity but now the two wake of dust up we can all be more alert but it is well what happened was you know i finished my ph d in california i had studied earthquakes in cairo and which was a earthquakes in their histories well we now appreciate that california is more dangerous than boston and the reason is because the earthquakes are much more frequent and you know for them in boston but we do have a history of damaging earthquakes so so for me it was interesting to come to a place where there was relatively little known about the earthquake activity and relatively little research that had been done after california where you have you know dozens of schools that are doing interesting and that because we do have a like all the earthquakes happen on the west coast we're perfectly safe here but what you're saying is no were right but it's a matter of activity that is a relative activity it's not like the east coast or the left to kick is a little more peaceful  miria and you put out seismic stations and do the same kind of monitoring you have to wait about one hundred years one hundred for years to get the same number of earthquakes as you get in one year in california both places it turns out the distribution of the earthquakes with magnitude is the same so for every one damaging earthquake let's say a magnitude six you get in california you get ten magnitude five earthquakes you get about one hundred magnitude for earthquakes you get about a thousand man and two three earthquakes you get about ten thousand maybe two two earth quakes same thing is true new england for every one damaging earthquake about ten million i see hundred magnetized fours thousand main two threes etc now it's one hundred those play out one hundred times slower yet and it is moving right at your throat still moving the plates are still moving yeah so you know where that is they have a damaging earthquake once every two or hundred fifty five two hundred fifty ronnie biggs right does that make you worried that maybe something could happen soon or well people will come to me and they'll say it's a doctor able they see we're due for an earthquake and the first thing i say is i'm but the second thing i say is i can tell you what the averages are but the problem is averages are not predictive yet i say and so i don't know for do or not so if you have a have and earthquake yeah and you have another strong earthquake a year later yeah and you have another strong earthquake ninety nine years after that the average time between those earthquakes was fifty years but the ask you about your work is there anything in particular that you really enjoy the most what's the most exciting thing i think the most exciting thing is they at as we study earthquakes more and more we're starting to see the patterns where they're current which for instance in this region which might be the faults that are active california which might be the faults that are react i say we can't predict earthquakes about it we're getting a little bit better at assessing when there are times when the earth has a higher probability of having or by sea and particularly strong earthquakes but the patterns are subtle and that makes them interesting from a scientific perspective but challenging also knows i would love to be able to give you the answer today when the next damage earthquake but i can't do it right if the if the parents were obvious people like charles richter would so surprised by earthquakes but every time an earthquake occurs i learn something new yeah yeah that and that's a very exciting thing you know is a research scientist in a laboratory they only learn something new when they go run their experiment in the laboratory where i can be sitting here and if an earthquake occurs i will look at the location i'll look at the magnitude go and collect more sophisticated data and i'll say oh gee i didn't expect there oh gee that's exactly the pattern i've seen before look this piece into the if right but what an exciting time to be doing this it seems to me because so much as global in terms of information and it might be easier to put patterns together i'm sure it's definitely easier computers are helping that we have new mathematical about as i say you do not i was you know with computer clusters and supercomputers and things like that we could do processing that we couldn't even if thought of even fifteen or twenty years ago so it's really exciting because there is so much we're learning now about the earth yeah is there anything that's particularly frustrating in this line of work i think the most frustrating thing is the fact that government funding for general is going down so so here is you know more money would allow us to make faster advances and the governments as well actually there's less money available this year gives last year  you know when you have fewer people working and you have less equipment to do the work the discoveries just don't come i don't know if the audience is aware of this is very widespread across fields that there's this cut back and cut back and if we could have for science what we spend in one week in afghanistan would really be very welcome i think you know because we we could really use the money in many sciences but there's a situation where you have to train people for a long time  and well and my and doing science has become more expensive yet over one hundred years ago people would buy a seismograph and they would set it up and then they would run it and they would look at it and say ok it's running and and there wasn't that much to do now you have you have computers they need to be programmed they go obsolete so you have to have seizures in the equipment constantly needs to be calibrated the equipment because it's very sensitive can very easily go a mess and so then it needs to be it needs to be fixed or it needs to be replaced and so so there is a much larger cost with doing so as well as you then there was let's say one hundred years ago interesting point yes everything becomes obsolete quickly well they becomes obsolete and some people don't like that but on the other hand i love it and the reason is because when i have an obsolete computer and i do get the funds to buy a new computer my computer is not i don't buy the same thing i'm by something that's maybe ten or one hundred or a thousand times better yeah that's a nice that's a that's a nice thing before we close the can i ask about the western observatory  the public visit places like that they just their laboratories or whatever we are set up so that the public can tour the observer her the only thing is we used to have a regular tour guide and boston college the funds have been cut and so boston college took the tour guide away so you there are restricted times when we get to give tours and oftentimes you don't get a seismologist but it is it is possible regulations to tour the observatory so you have to contact the observatory right that's just good it's good to know because the group could go for a class could go possibly said that it is possible to do it right you just have to contact the observatory and see if funding well i appreciate the opportunity because anytime i have a chance to educate the public about earthquakes i think it's a it's and they love to hear it thank you very