May 18, 1980 Mount St. Helens Eruption: Stories from USGS Scientists

i figured that i was going to live my life and go through my career in the u.s as a volcanologist without ever seeing an eruption within our borders and so i pretty much figured that i'd have to go outside the country to visit erupting volcanoes so when mount st helens woke up in the spring of 1980 it was too good to be true i could hardly believe that it was really happening especially because i was very familiar with the volcano and i knew what kinds of things it had done in the past and i knew the geography around the volcano and i so it really had an impact on me one of the things that we'd kicked around is um incessantly from probably 1960 to 1975 is when will one of these erupt which one will erupt first what's the chances of it erupting but by the time we realized that it on it was an order of magnitude more active than the other volcanoes so it was pretty clear it was not it was not a difficult call to say that saint helens in terms of probability would be the next one done and so my hands were shaking so bad i couldn't reload my camera put another roll of film in it the first thing that came in was a report from spirit lake they'd heard two big booms this as i remember it and then very short time later became the reporters transmission from an aircraft that he could see a plume coming up through the clouds i think he could not see the volcano at that time that meant it had really happened and the world was going to turn upside down we had some pretty strong discussions about whether or not we should be in the volcano around the volcano etc for personal safety reasons and the other side taking what we got to get the science while available and i i remember that the hazards team crandall molino hoblit and miller who were living in denver at the time that we received a notification very early on right after march 20th when the first earthquake began and that was the beginning beginning of the most hectic i don't know 10 12 months of my life i guess we watched very closely as the earthquake swarm escalated in march and on the 24th of march i think it was don mulino came out here to vancouver and um i think it was the 27th of march recoblic came out and then at noon on the 27th there was the first explosion and that got me going and so i got in an airplane and showed up at portland airport at two in the morning on the 28th of march i mean i remember two in the morning because i immediately rented a car and raced over to to vancouver to the forest service office and ran down into the basement and looked at the seismic drums to see what was happening and that was the beginning of a you know 18 hour a day seven day a week seven month investment of my time and energy trying to figure out what was about to happen and then dealing with it after it did happen and there was this big press conference with several tv cameras the national media were there and the forest service and the usgs people were were talking and i had to give a spiel about what i'd seen which was essentially nothing but so my first impression otherwise was one of of uh not quite chaos but certainly uh and unmanaged a situation where where we were just uh reacting to what the volcano was doing rather than then knowing exactly what was going on because because of this bad weather and the nighttime observations one of the best comments or the most illustrative comments was by a state forestry man who stood up and said in this room he said do you mean to tell me that we can put a man on the moon and you can't even tell us whether the volcano will erupt or not and i said that's correct we cannot tell people just assumed we should be able to know and then that was the 26th the 27th at noon was the first of about noon was the first pop and then things spun wildly out of control as far as as my part of it went because it was just 20 hours a day of questions tried to explain things to people reporters came in swarms volcanoes don't take the day off so you work seven days a week but rocky and i had been around so much that we knew the details of the geography as what as well as the geology that we were trying to explain to people and that was a great advantage because we had to with many people we had to establish credibility to a skeptical group we were sitting in in in the in this jeep that i had i mean this whatever it was a ford bronco i think um by one of these cans that andre and i had set out to collect ash i wanted to just see what it was like and i looked in it and was sitting in the note in the car after that taking notes and barry i was i was in the driver's seat barry is on the other side this earthquake occurred long long long when you're in a vehicle sitting still with the engine not running it's really in the vehicle itself you know with a higher center really accentuated we just swayed back and forth and it lasted just seemed like it lasted half a minute but it wasn't that long it was quite impressive um that's the certainly the one i felt the most of that of that period and uh about 15 minutes later when we threw we drove down and we stopped in at harry truman who would come out of his lodge and he sort of waved us in so we went in and had a he had a coke or something with him he was drinking his typical coke in a coke glass what looked to be coke but it was coke and whiskey of course and so we had quite a chat with uh harry harry said that that is the earthquake everybody's going to talk about all the chandeliers swayed east-west here not north south as they had before and so it was a highly charged atmosphere it was very exciting it was pretty i guess it was frightening to be on the volcano we were having earthquakes of quite regularly 3 magnitude 3 sometimes over 4. we couldn't believe the results because the results showed absolutely no change between 1972 and 1980. even though visually we could see the north side of the mountain changing that meant that the east side was not changing at all and so this this coupled with the fact that the spirit lake tilting didn't show anything told us that all the deformation on the mountain was was local to the mountain and even more local than that was on the north side of the mountain only so we were really able then to focus in on that part of the of the volcano rather than frittering away our resources uh by looking at the entire edifice by the time i got here the bulge uh was obvious and we were measuring the rate of of of northward movement of the the bulge at about six feet a day and we knew that wasn't so good um in the nearly two month period before may 18 what was essentially happening at mount st helens was that magma or molten material was moving up from some deep reservoir beneath the mountain up into the volcano itself and what basically happened is that this viscous magma moved up into the volcano and it began to grow or form what we call a dome or a cryptodome inside the volcano and that inflating body of magma or molten material actually broke the north side of the volcano and began to cause the north side of the volcano to expand out toward the north this was what was happening for the two months before may 18. there was a growing wave as this thing went and i'd been through several that size before so i knew it was coming so i had to take down both instruments lay them on the ground because they would have been knocked over and and then i sat there and tried to ride it for a while and it just threw me on the ground it was just it was that much of a of a rolling uh earthquake and it seemed to go on forever the morning of of may 17th a german visiting graduate student and i uh went out to re-measure uh the stations and we started at butte camp we had we had uh three different instrument stations that we occupied butte camp uh toodle which was above the south fork toodle uh on the divide between the south fork and north fork two and then timberline parking lot so we started started at butte camp and the day before or a couple days before i had heard from jim moore who was in in menlo park that it looked as if on the basis of the photogrammetry it was being done that maybe the south side was starting starting to move a little bit too so i decided to put in a new reflector station for the geometer in the theater light uh on on the summit of the of the mountain but south of the main crater and so we flew up to the two of that area mid-morning on on may 17th and i i put the i established the reflector and the the german graduate student was on a butte camp and said he could see a signal and so forth it was a beautiful day up on top warm and sunny so the pilot shut down the helicopter and the two of us um walked over to the lip of the crater and peered down into the crater and and spent spent some time there and then walked back through really really almost slushy snow you know more than 9000 feet but it was just really really wet and mushy and and so we got back to the helicopter i guess and flew back down to butte camp between 10 30 a quarter to 11 something like that um dave johnston then who was going to spend the night at coldwater 2 did that's where he died went into the crater even later than that he uh he was flown in in the um sometime in the afternoon on may 17th and actually walked down and collected a sample of water from one of the meltwater lakes down the bottom of the crater and so he was the last person in in the crater so far as i'm aware on the morning of may 18 i was driving up interstate five headed up to the north side of mount st helens with some parts and some batteries for our time-lapse cameras and as i glanced over at mount st helens um it was a beautiful blue sky day and the mountain was sitting out there and suddenly i saw this mushroom cloud go up above the volcano and climb rapidly up into the stratosphere and i had seen a number of the small steam explosions that had been occurring for the two months prior to may 18 but i had never seen anything on this magnitude and i knew that it was a huge eruption compared to what we'd seen so far and so i crossed over the center line and and headed back into vancouver and raced back to our office well on the morning of may 18th we had our normal uh meeting at seven o'clock or thereabouts earlier that morning dave johnston had been able to make a measurement with using the range master that he had uh cold water two for he measured from there over to the goat rocks on the on the uh volcano and found that there'd been no change in in rate of of movement actually a slight decrease in rate of movement since the last time the measurement had been made some some time before so that was that was reported at the meeting and then i was preparing to go up and replace dave that morning but someone was going out to get some supply some groceries and so forth and said hey i'll get some groceries for you too i don't remember who that person was now so i didn't go right away but waited around at the forest service building for the supplies to come and i was down in the in the room where the seismographs were at 8 32 in the morning and i i heard a sound i just looked over my shoulder probably just a split second after the um earthquake the big earthquake had started and saw that this was something very large larger than we'd seen before watch it for a few seconds just to confirm that and then i ran upstairs to the next floor up to the radio uh desk of the forest service and uh called uh called dave and i what i wanted to do was to ask him if um if anything was happening at the mountain and we couldn't get through there was there was no there was no answer and ran over to the radio and tried to raise dave johnston and uh gave him a call and and when i didn't uh even i didn't hear from him and i didn't hear the repeater answer me back and our repeater was located up on coldwater peak which was quite a ways north of johnston ridge and way up high and so i suddenly realized well something really serious has happened if if coldwater peak has been blown away and the repeater is is destroyed then i figured there was something awful had happened at coldwater too as well so i guess i had the realization right away that um this was some kind of a tragedy and on the one hand it was this huge exciting and interesting magmatic eruption and on the other hand it was i was pretty certain that something terrible had happened to dave so it was a it was a strange day for me the forest service got phone calls saying that some people were seeing an eruption column starting from the from the volcano and so uh uh i i drove to pearson air park uh immediately and i don't remember if if i was ordered to do so by bob christensen or if it was just decided that i would go uh the forest service had a spotter plane ready to go dave gibney the their normal pilot was there remember this was early on a sunday morning it was amazing and we were off the ground probably at uh 905 or something like that i mean it was really really rapid and got up to the to the point where we could really see the mountain well i suppose between 9 20 and 9 25 something like that by that time um the blast had been completed um of course we we could never get around to the north side of the mountain so i couldn't see what had happened there but we we were able to see the south side very well the flank was scored by mud flows it come come down it there was this terrific very vigorous vertical eruption column uh there was the stem of the mushroom or the toadstool it then blossomed out at greater height and we could see during the course of the morning small pyroclastic flows starting down at various places down the south flank never getting very far but and uh for most of the morning we saw this tremendous whenever we could get around toward the west side of the mountain saw this tremendous ash cloud roiling out toward the toward the northwest and i can only assume that that was uh coming off of the big pyroclastic flows that were going off in that direction that later built the pumice plane it was a very eventful morning but it was sobering because i remember thinking up in the airplane that dave just couldn't have survived this especially when we got around to the west side and saw all this ash headed in his direction um it was totally quiet to us in the airplane because of the drone of the airplane engine i guess just just we could all we could hear was that and the conversation in the cockpit and radio people were radioing in telling us that there were mud flows uh in various river drainages we could see those uh in all the drainages except for the main fork of the toodle um but it was it was a almost a surreal uh experience because it was so quiet we could see so much happening and we were in this this kind of cocoon in the airplane that we that we couldn't escape from uh i was out there on the plane uh in the plane until it had to come back to refuel i think around one o'clock or so that day you had to see it to believe it to get that total impression so that when people through the summer came said they wanted to see what happened i would suggest to all of them that they first go down to pearson field and buy a ride on the plane and go up and and make a loop around the mountain because i thought only then could you really understand how the part you could see from the ground fit in with the overall eruption and it was it was stunning to see those small increments that you could see on the ground and realizing that that is such a small part of the overall devastated area or the affected area on the morning of may 18 what actually happened was that a magnitude 5.1 earthquake caused this weakened north flank of the volcano to break loose and to slide under the influence of of gravity down into the north fork of the tudol river this was a gigantic landslide that was the first event in the series of events that occurred on may 18 the landslide basically uncorked this pressurized body of magma and allowed it to explode or expand out towards the north very rapidly this is what we call the lateral blast it was a horizontally directed explosion of incredible magnitude it caused this expanding cloud of ash rocks and gases to move out across the countryside to the north at speeds of several hundred miles an hour the directed blast was really the most destructive event that occurred on the morning of may 18. it completely destroyed an area of 230 square miles in the matter of somewhere between five and nine minutes it essentially killed every living thing um within an area of 230 square miles and it destroyed hundreds of acres of virgin forest and was an incredibly spectacular event there were places uh north of the volcano which was left pristine there was old growth in there because it was a major play land for the portland area and just huge huge trees and you could walk in there and not hear sound because of the vegetation that and it was just a gorgeous wonderful wilderness there and to know that in your mind i actually haven't seen it four days beforehand and come back and see it all gone that was quite a shock it took me about two weeks of flying across the the boundary of the the blast zone before i i stopped having that physical emotional hit the first two weeks after may 18th are kind of a blur to me because uh so much was happening so uh so quickly in general though i'll tell you that that i along with jim moore and pete littman spent the the a full day on may 19th uh flying around trying to figure out what had happened on may 18th and we got the general picture uh yeah in order then although of course the very important details were done by others later on but we wanted them to us to re-establish as much as we could of the older geodetic network that we've been used prior to may 18th and so over the next few days as time permitted we would revisit some of the old reflector stations and they were all damaged beyond repair but we would we tried to recover a couple of them and got approximate uh changes over the or the eruption we put out new stations uh and we quickly started to uh re-monitor the volcano again because we had no idea what was going to happen down the road and we we thought it likely that there would be more eruptions during the summer and indeed that that took place later i wondered if harry truman had maybe painted himself into a corner by being so firmly saying i'm never going to leave so even if he had at some time become convinced that it was too dangerous because it it didn't take an eruption to wipe out harry just a landslide failure of that expanding bulge would have taken him out i think so this avalanche came down the north fork toodle and just pushed all the trees in the valley out of the valley down at the head of this avalanche so the front end of the avalanche was this big giant pile of trees and fence posts and and bushes and shrubs that had been just scraped off the valley floor and were all down at the end of the of the avalanche the uh when i when i was flying in the airplane on the morning of may 18th i was using an old bell and howell uh 16 millimeter camera with the spring wind-up thing so you could only take a scene for 10 seconds or whatever 15 seconds something like that and run out um i had seven or eight uh 100 foot rolls of film with me that i i exposed seven of them this is the old camera that uh i used the old movie camera that we used uh for uh filming the may 18th eruption column it winds up here um i've got it all the way wound up here uh look through a site here and just push down and i'm filming you all right so this episode at mountain helens which began on may 18 actually culminated in october of 1986 when the last magma came out of the ground um obviously for volcanologists in the united states the the mount st helens eruption was a spectacular learning opportunity and before the dust had literally settled in the summer of 1980 there were usgs scientists swarming all over the area out in the blast zone studying the pyroclastic flows studying the debris avalanche deposit studying the directed blast deposit and basically looking at all of the different faces of the may 18 event so then we'd have a meeting with everyone who would either bring in their data and discuss it and what they thought about what the volcano was going to do so there were some crews that were looking at what the volcano did during that eruption so there were there were months spent investigating the may 18th deposits and then there were people who were out measuring deformation and the the real-time situation at the volcano so to try to to discern when the volcano what the volcano's gonna do next trying to trying to recognize patterns that the volcano was going to do so these discussions would last an hour an hour and a half of reporting what had happened that day jimmy carter came on a certain time and the day after that people throwing helicopters at us so from that point on we had no nobody had any trouble getting into the field who wanted to and uh i teamed up with dan zurich and we had this beautiful a star french a star brand new helicopter that cascades helicopters got and the president of the company is flying it's very proud of it i don't know why he'd bring such a thing into such an ashy environment but it was it was in the wake of something exciting local it's called cascades helicopter i mean how can you not have that name how can you have that name and not fly now st helens so we had this beautiful ship um we that was when i started doing the enclosed stratigraphy and i already had a you know a handle from outside so i was bringing the same stuff in you know systematically and we flew in around you know spirit lake and put in stops there and you know graduates getting into thicker stuff and there were other things besides airfall deposit of stuff that fell out of the sky to work on it and it just was part of the same stratigraphy so that's what led me eventually into other things anyway it was really clear that there was nothing left at cold water too and the car was gone the trailer was gone and there was no indication of anything there but we landed just down blast from cold water too at the bottom of the south cold water drainage on these new hot deposits and i tell you it i mean it was like walking on the moon i will never forget the feeling we had we asked the pilot to keep the engine running first of all he had he had to shut touch down very gently and try to move it around and find some solid place because the blast deposit was very soft and very um irregular in places and quite inflated and there was smoke coming out of their steam and coming out of the ground in hundreds of thousands of places out there so it was like it was like walking on the moon there was nothing living as far as you could see in any direction there was no sound except the helicopter running and no insects no animals nothing green just gray it was just i was out of this world sort of experience and every step you took was the place that nobody had ever actually had stepped before it was sort of it made an impression of course most of the time we were working our tails off and we were all exhausted we were working 20 hour days seven days a week so there wasn't too much philosophical introspection at the time although it hit you once in a while and so we were out in the field on the on july 22nd in a helicopter and we were down looking at some mud and and on the north fork toodle and we were out of radio contact and so when we got it back in the helicopter took off flew back to the volcano and came up from underneath the clouds and here was this 20 thousand foot ash column rising up and the radio going it's still at 30 000 feet and climbing and where we were in the helicopter you couldn't look up to the top of the of the we were so close you couldn't see up to the top of the of the column of ash and so that whole next several hours were full of we were running out of film because we didn't have enough film it was like a battle with not enough bullets you know more ammo and had to count all our rolls of film and see how many we had so we could make sure everyone had a couple of rolls of film um we had landed on the ground and and one of the geologists was taking a temperature measurement of the ash flow and he had his back turned to us the people in vancouver were telling us to get off the ground because they didn't know what the volcano was going to do and we were right next to an ash flow another asphalt coming down would be right where we were and we couldn't nobody wanted to get out of the helicopter and go get this go get the other guy and pull him into the helicopter and there's no siren or anything to tell him to come back so it wasn't until he had finished and finally turned around we were all get back in the helicopter so rick and i got out and we ran around and wandered around in this hot stuff trying to keep from sinking in and burning ourselves and there were these weird little volcanoes that were produced where these fumorals were coming out of the ground and material had piled up to form these little miniature volcanoes and the whole area had this incredibly strange organic stench to it because of all the cooking vegetation and the distillation of vegetation that was taking place under the under the surface i remember rick and i dug some holes and there had been a light rain on the top of the blast deposit and so the upper part was wet but when you dug down a few more than a few centimeters or so it was gray and white and hot and it was just like hot ashes and when you tried to dig a hole in it with your shovel these stuff would just flow back and forth like hot fireplace ashes i guess what amazed me is some of the some of the events one of them one of them really amazed me is what happened at spirit lake and we still haven't told that story it's a sort of hidden story but it's very clear um probably this maybe the third day of his helicoptering with zaryan we landed over at harmony falls and you can see the whole shores of the lake have been stripped of trees the trees were down and that they weren't really stripped by the blast but they were all laid down but then below a level is like a line below that and every tree was gone from that and the log was full of i mean excuse me the lake itself was full of logs and so it seemed to have been a big slosh of water around there and it rinsed off the lower slopes and it put the timber in the lake that's why it was there so i mean the timber all the terminal leg didn't make sense there's no way for it to be thrown in but you could see if it's washed in you started working on that a little bit you realize jesus when you get up it was hundreds of feet i don't remember now maybe 600 feet or so above the lake um that this water had clearly washed to might have even pushed it higher 650 feet little later and i realized that this was hot it was a piece of the kryptodome and it was so hot it dried out the ash and kept it dry even though there had been some rain and so i bought out a big plastic sample bag and i picked up this rock and put it in this carefully quickly and put it in the sample bag and then when i turned around to look somewhere it melted its way right through the bottom of the bag anyway it was incredible hoblit and i were were blown away by what we saw we stayed there maybe half an hour or so while the helicopter was running and we just couldn't get enough of it i mean we were taking pictures running around digging holes it was um it was incredibly exciting and very interesting and all new and intriguing and then we got in the helicopter and we flew around there was it was still very dusty um and there were friatic explosions rootless free attic explosions taking place above the north fork of the tudol river out in the pumice plain and some of those were going to 18 or 20 000 feet so um it was a pretty hard place to get around in a helicopter because there were a lot of ashy places that we really couldn't visit um safely without getting into the ash we got to uh the forest service kept a airplane around the mountain 24 hours a day for six months or more um and so the opportunity to go on that airplane and fly for three hours around them watching the volcano and looking at things was was available for us so i used to go out at three o'clock in the morning get on the airplane view the volcano in the darkness and so you could see the glowing lava from the vent and you could also see all the burning trees that were blown down the trees actually i mean a lot of the forest caught on fire from the blast and the hot rock and this stuff was burned all year until the snow and then the next spring when the snow melted some of the big logs were still on fire and started seeing a couple of those places around the mountain in the next spring in 81 up in the head that would be the north end of the west arm of stuart lake spirit lake is kind of like this two-fingered lake and the head of that is called bear cove up in there there's our chunk of the debris avalanche or landslide i was calling it um that was pretty amazing because you have for it to get there what it meant is the landslide came down off the volcano across the plain went right through where truman's lodge was into the lake they must have ridden the floor of the lake bottom all the way and come up on the other side and there it was a big deposit about up on that upper and the leg is huge hummucks of you know dayside and basalt and stuff stuff that come off the top of mount st helens and this this crazy hummucky pattern that we have begun to recognize is somehow indigenous to that particular slide and this might have been later i think that actually might have been in july when i went up there for the first time i can't remember now um but i just remember being being so impressed but i think it was it was july or even august being so impressed by it so there were the hummocks and behind some of the hammocks that is on the side away from the lake there were gigantic log jams um they they're still there probably but it was really but they were just they're clearly water laid there were rocks in them and uh huge things almost as high as the hummock and and they were on the on the north side of the hummocks so that was a record of water they've been jammed up into that arm and gone way up on the slope which you could see that you could still see this line of course there below and trees laid down trees above it that's a record of that water having been thrown up there and rushing back to this huge flood into the lake again and making these gigantic log jams um on the back side so the on the sides of these hummus a side away from the lake the the pyroclastic flow had floated on some sort of pneumatic cushion and not even dropped things through a lot of that area because it was moving fairly fast down to that area and then so there's this great big pond so you could actually walk on 18th deposits right down to the pond and then there was this pond of this new stuff and so i was in fig 7 for for measuring temperatures there was this huge pond that had actually been deposited oh less than eight hours beforehand so i went down and decided to walk out on it and of course the first step my my foot disappeared up over the boot top and this this fluff it was just very highly inflated uh powder and it was inflated with air hot air basically you had to incorporate it on the way down the mum but i wanted to get out on it so so i realized after a couple attempts that if i did a tentative pat pat to see whether i was going to sink in i sort of formed a snowshoe or an ash shoe and the more i padded the more funerals i would generate and the bigger the the area would get so you could actually pat it enough so you could deflate enough of that deposit to make it sort of a shoe and you could stand on it and then you could do it in the second so you'd walk out doing the petty petty pat and petty petty patent so i got out quite far on this pyroclastic flow and was able to measure a temperature uh profile both vertically and laterally through this thing but if you took one step without doing that of course you just disappear and and it was pretty hot 650 degrees centigrade in about after about two hours of circling over this and not seeing anything suddenly this immense black eruption cloud came pouring up out of the white um layer that the cloud tops and i couldn't believe my eyes i mean i thought this is the most incredible thing i've ever seen in my life but eventually what we did was we we got big boards two by uh two by twelve by twos and put uh uh straps on riveted straps on the top of them and they were you know maybe give you about two square feet of thing and then you could walk on it without doing the pad pad start to smolder yeah oh they burnt yeah you they're all they're really good for they're really good for about two or three days then yeah go get a go down to the lumber yard get a new pair a lot of innovation in those days the things that we did tried to cope with the fact we didn't have the right equipment at the time so the first time the engine the helicopter turns its engines off and it wasn't quite in the crater the crater was full of noise i mean rocks crashing and you could hear you know continuously rocks falling down the crater walls and crashing and there were hissing noises of funerals around the sides of the dome that that we had never never heard of them before because the helicopter was always blanking out this sound and so that was a it was a kind of a realization that there was something else happening in the crater that we hadn't experienced yet but it was truly um only the beginning of an eruptive episode that lasted for a little over six years so the first explosion occurred on may 18 and then there were several sizable explosions in the summer of 1980 and they say it sort of trailed off until october of 1980 and then for the for the next five years or five and a half years there were a series of dome building eruptions um in which molten material came out very viscous pasty lava came out on the floor of the crater and piled up to form a dome or a mound in the middle of the crater floor a feature that's now about 900 feet high sitting on the floor of the crater so this episode at mountain helens which began on may 18 actually culminated in october of 1986 when the last magma came out of the ground and we've noticed that there were cracks developing on the crater floor that radiated out from the dome more or less like spokes radiating out from the hub of a bicycle wheel we didn't know if that cracking represented cooling of the hot crater fill that had been in place on may 18th or if it represented swelling uh and extension of the of the of the crater floor so we just we decided to start monitoring those cracks just to see what we could learn about them and we brought out pieces of rebar a footer too long and drove them into the ground and got out our trusty tape measure and simply tape measured the distance between these rebars what we found is that leading up to the explosion and dome growth in late october that the cracks we were measuring were opening and they seemed to be opening at an ever increasing rate leading up to the last period of measurement before the dome growth so that was kind of interesting but just just just one of a kind and so uh uh after the the the dome had been enlarged uh in october uh and things had quieted down we went back in there again uh found some of our old stations and put in new crack measuring stations and measure them through november and through december and uh there was the cracks were widening again and had an ever increasing rate which led up to the dome growth at the end of december it doesn't take a rocket scientist to recognize that that there were uh two periods that looked pretty much the same so maybe this is predictive so in uh in january we started doing the same thing we also started climbing on the dome at about that same time but we were continuing our measurements of the of the cracks and this the opening started to accelerate again and so at some evening meeting we head over to forest service building i told don peterson who was the scientist in charge here then don i i think that uh we're going to have another dome growth a period of dome growth within x days from from now based on the cracks and he was intrigued and we decided not to say anything publicly because we only had these two examples to go on lo and behold we saw we saw the same pattern before the next growth which i think was late january or early february and so therefore we we felt pretty good about that so so the next time around leading up to the uh late march uh event we again saw this this pattern of increasing rate of opening and so we then started going public and started making predictions with uh whether with a time window within which we thought the eruption would occur on the basis of the rate of of of opening and and it worked and we all felt very very good about that very simple obviously simple technique basic just making a measurement with a tape measure uh but this this this worked remarkably well and was very useful uh to us and to the forest service in anticipating when the next period of of crisis would would be there was one time when i i knew i smelled bacon and eggs in the crater and there were one of the crews was cooking they come up with in the morning with breakfast and you could cook it over the hot cracks fried eggs and bacon and stuff we we learned a lot about how you interact with the civil defense with the public with the press and that was transferred by the press to the world and as a result i think volcanology took a a multi-giga quantum leap in in science as well as applicability to to society's needs and i think it was probably the most important corruption in the history of volcanology i think all of us were a little numbed by having [Music] lost dave johnston i knew two other people who were killed in the eruption as well and um so we were um uh both more wary of the crater than we might otherwise have been because that was the the source of the problem uh and also i speaking for myself i was also um motivated by those deaths to try to do better than i was doing before two down the road try to save lives that uh to kind of make up for what for for the loss of our colleagues so i think we were we were both uh cautious and and moved to do to do better as a result of what happened on may 18th the subsequent eruptions were actually most of them were forecast fairly accurately by the usgs team of scientists so when it looked like another explosion was about to take place our helicopter crews would pick us up and we'd move out to the outskirts of the of the blast zone we'd watched and photograph the next eruption as soon as the eruption stopped we'd race out there and study the deposits while they were still hot while they were just after they'd settled onto the ground so it turned out that the eight years that mount st helens was erupting in the early 1980s was an opportunity an unprecedented opportunity for usgs scientists to study hot fresh young and exciting deposits from explosive volcanism and we basically we learned incredibly new and important bits of information about how volcanoes like mount helens work what kinds of deposits are produced during these explosive eruptions and how to anticipate and mitigate the consequences of explosions you

Channel: USGS

Views: 31,017

Keywords: usgs, science, Mount St. Helens, eruption, ash, earthquake, landslide, hazard, field work

Id: p5RohaQ3wfk

Length: 45min 20sec (2720 seconds)

Published: Mon May 17 2021