On the same date in January one year apart, Earthquakes of almost identical power shook Northridge, California (1994) and Kobe, Japan (1995). NOVA probes why almost 100 times more people died in Japan than in the United States and what scientists have learned from the twin calamities.
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00:00Tonight on NOVA, January 17th, 1994, earthquake, Northridge, California, damage in the billions.
00:08Exactly one year later, Kobe, Japan, same size quake, but this time there are deaths in the thousands.
00:16What happened in Kobe could happen in L.A.
00:18If a quake like that were to strike, we could have conflagrations in the city like that.
00:23Does an earthquake have to be a disaster?
00:27The day the earth shook.
00:30Funding for NOVA is provided by Merck.
00:43Pharmaceutical research, improving health, extending life.
00:48Merck, committed to bringing out the best in medicine.
00:53And by Raytheon.
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01:02Raytheon.
01:03Expect great things.
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01:13On January 17th, 1995, Japan had its worst catastrophe since World War II.
01:29The city of Kobe was ripped apart by an earthquake of magnitude 6.9.
01:35More than 5,000 people died.
01:46One year before, to the day, Los Angeles nearly suffered the same fate.
01:51Good morning.
01:52The time is 4.30 on Monday, January 17th.
01:55The suburb of Northridge was hit by a quake of magnitude 6.7.
01:59We're having an earthquake.
02:10Relax.
02:10Just stay right here.
02:11We're having an earthquake.
02:12Relax.
02:138,9,1,1.
02:14What is going on?
02:15The earthquake.
02:16many people were seriously injured and 57 people died but the city of Los
02:23Angeles itself had a narrow escape what I can say is we've just experienced a
02:27real whopper here
02:30two cities two earthquakes same date same magnitude but casualty figures that are
02:46very different why comparing the two earthquakes scientists have reached
02:52conclusions that are both alarming and hopeful a big city earthquake will happen
02:58again but it need not cause massive loss of life
03:09many scientists believe that it should be possible for no one to die in an
03:14earthquake but only if the lessons of these two earthquakes are learned only if
03:20the stories they tell or heard a young teacher who lived through the Northridge
03:32experience Makiko Yoshihara later returned to Japan
03:40she continues to teach nursery school children near her home in Kobe 500 miles
03:46southwest of Tokyo
03:51in the early morning of January 17 1995 15 miles below the surface and almost
03:59directly under the city of Kobe the earth was preparing to shake again in the
04:06office of a television station a security camera was watching
04:11firstly I was lying in bed and felt violent movements up and down and then sideways I was very frightened my sister was about to go to work and she was up she held at me big sister get a flashlight the crashing went on for a long time
04:40I was very scared
04:42I was very scared my bookshelf fell down I could hear the cupboard rattling and the dishes cracking inside
04:50I watched the TV come crashing down and the VCR and even the piano was moving around in its place
04:58as to Kobe and Northridge it seems really strange to have been in two such big quakes in my lifetime
05:10outside Kobe the first anybody knew about it was from the television network NHK
05:16along with the weather information the morning show from Tokyo carried reports of an earthquake being felt all over Japan
05:28seismometers in central Japan were showing ground shaking at magnitude 4
05:34but the seismometers in Kobe were silent knocked out by the earthquake
05:39nobody outside the city was aware that many parts of Kobe were already on fire
05:51ignited by sparks from fallen power cables broken gas mains blazed
05:56toppled oil stoves recently lit for breakfast added to the fires
06:0820 minutes after the event Tokyo got through by phone to reporter Norio Seki in the Kobe newsroom
06:16he had been asleep waiting for his shift to start
06:26at first I felt a slight movement
06:28it occurred to me that it might be an earthquake
06:31then the violent shaking started in all directions
06:35I curled up inside my futon
06:38the lights went up because of the violence of the shaking
06:42I was so scared
06:46what I remember most is that I was so scared of the darkness
06:5020 seconds later in Osaka
06:5630 miles from Kobe
06:58staff in the NHK studio were also shaken from their desks
07:02but to a much lesser extent
07:04it was a full half hour later that Japan's central seismic computer plotted the epicenter
07:14just southwest of Kobe
07:16just southwest of Kobe
07:18by now entire sections of the city were in flames
07:24small fires became conflagrations
07:42many hundreds of people died in the fires alone
07:48survivors were unable to do anything but watch in stunned silence
08:00the lack of seismic information had meant that fire and rescue services were not immediately alerted
08:14then compounding the tragedy
08:20only a few roads were open
08:22most were blocked by earthquake damage
08:26when they got through
08:30the firemen faced a classic dilemma
08:32to help people trapped in burning buildings
08:34or to get the main fires under control
08:36they were well equipped
08:38but not for a battle on so many fronts
08:44they soon began to run out of water
08:50the fires had been so large and unexpected
08:54the emergency tanks underground were just not big enough to cope with such a demand
09:10to cope with such a demand
09:22dawn began to reveal the full extent of the horror
09:24the destruction made a previously peaceful city seem like a war zone
09:30one of the worst hit areas was the district of Nagata
09:44this was the market arcade
09:46surrounded by houses
10:00many died in their homes right here
10:04Kobe shoe factories with stockpiles of rubber and chemicals
10:18had provided extra fuel for the fires
10:20an entire community had been burnt to the ground
10:28over a thousand people died
10:30nothing like it had been seen in Japan since World War II
10:38and the death toll was to mount further
10:42outside the fire torn areas
10:44many lay buried in rubble
10:46across the city
11:04rescue work was carried out by neighbors
11:06and desperate relatives
11:08the man is calling for his mother
11:16buried somewhere below
11:18the man is calling for his mother
11:20buried somewhere below
11:22the man is calling for his mother
11:24buried somewhere below
11:26NHK reporters were shocked
11:28by what they found
11:30I'm in the middle of this area
11:34please look at this
11:36the second floor of this house just fell down
11:38look at it closely
11:40the first floor collapsed
11:42and the second floor fell down
11:44and everything fell out
11:46two people were rescued
11:48and one person died
11:50wood framed buildings had simply been shaken to pieces
11:54the contents either killing or severely injuring the occupants
12:00so now please
12:02look at this over here
12:04on the roofs of these traditional style houses
12:06were heavy tiles
12:08protection against typhoons
12:10but lethal in earthquakes
12:12supported only by timber posts
12:14they were responsible for many deaths
12:16as you can see
12:18the tiles were broken
12:20and this piece of wall
12:22it's made of straw and mud
12:24so many old houses like this were damaged
12:28or collapsed completely
12:30the tiles broke into pieces
12:32and even the symbol of the house fell
12:36on every roof was a heavy stone ornament
12:40symbol of life
12:42the final toll was horrific
12:54more than 5,400 people died
12:58it was far worse than Northridge
13:00where the death toll was 57
13:02ironically
13:14seismologists need earthquakes
13:16in order to work out what is happening underground
13:18now
13:20they understand what caused both of these earthquakes
13:22and why
13:24one or two known faults run under Kobe itself
13:32but there are many fault lines in the Kobe area
13:36the whole of Japan is crisscrossed by fault lines large and small
13:40Japan sits on the junction of no less than four tectonic plates
13:44segments of the earth's crust
13:46the Pacific plate
13:48the Pacific plate and the Philippine sea plate
13:50are in collision with the Eurasian plate
13:52and the North American plate
13:54each plate is forced to slide
13:56under or over the others
13:58all this conflicting motion is responsible for the sudden movements on faults
14:08near plate boundaries
14:10which we feel as earthquakes
14:12northern Japan is sitting on a corner of the North American plate
14:18this huge plate spans much of the Arctic and most of North America
14:22a sliver of California is cut off by the plate boundary
14:28San Francisco is on the edge of the plate
14:30while the coast of Southern California is on the other side
14:34Los Angeles is sitting on the Pacific Ocean plate
14:37and it's being moved to the Northwest compared to North America
14:41at a rate of just under a couple of inches a year
14:44it's about the same rate that your fingernails grow
14:46and in five to ten million years
14:49we're going to have Los Angeles as a suburb of San Francisco
14:52or San Francisco as a suburb of Los Angeles
14:54depending on your point of view
14:55and in 50 million years or so
14:57we'll be actually heading up into Alaska
14:59giving up on our palm trees
15:03the plate junction is not straight
15:06there's a bend near Los Angeles
15:08where the plates grind together
15:10as in Japan this produces cracks in the plates
15:14just like broken crockery
15:16some of the fragments rise up over others
15:20and this gradually builds mountains
15:22both in Japan and in California
15:28one very small part of this process
15:30was the earthquake at Northridge
15:32as with Kobe
15:36the seismologists had trouble locating the epicenter
15:39communication with some of the seismic stations was lost
15:43and others went off scale
15:46the traces had square tops showing no peaks
15:50it took nearly an hour to pinpoint the epicenter on Northridge
15:55the waves from it came up
15:57and hit a lot of our stations at almost the same time
16:00and it fit the pattern for microwave noise
16:02basically the computer said
16:03the ground is moving in so many places all at once
16:06this can't be real
16:07this must be a glitch in the microwave system
16:09and threw it out
16:11so when we got in there
16:13instead of coming up with a location like we would hope to do
16:15we often get a location within two minutes
16:17instead we had the system saying
16:19oh nothing's happened
16:20well yes there was a bit of noise in the system
16:22nothing's happened
16:23and we had to retrieve it
16:25when they went to retrieve the seismic record from the ruins of Kobe
16:29they found they had similar problems
16:31the seismometers had successfully survived the earthquake
16:35but there was no communications link back to base
16:41the traces showed that once again
16:43the instruments had gone off scale
16:45the peaks had square tops as in Northridge
16:48the seismometers were just not sophisticated enough to cope with a massive earthquake
16:53as many as twenty or thirty small and medium sized earthquakes occur everyday in Japan and in California
17:06much time and effort has been spent on searching seismic records for patterns which might help predict the big ones
17:13no patterns have appeared
17:16many methods have been tried but except by chance not a single earthquake has yet been successfully predicted
17:23Kobe and Northridge both lie in earthquake prone regions but neither is on a major fault
17:31both earthquakes were rather unlikely earthquakes which is an important point to stress
17:35that they're not the earthquakes that most people would have said would affect either Los Angeles or Kobe
17:40so it's important that we recognize that earthquakes will occur in unexpected places and at unexpected times
17:50both earthquakes had several unexpected elements
17:55on Awaji Island south of the Kobe epicenter
17:58cracks in the surface of the ground could clearly be seen
18:04but in Kobe itself in among the rubble no fractures in the ground were apparent
18:09the fault line was invisible
18:12without an array of seismometers it is hard to tell how the ground has actually moved
18:19at Yokohama University Professor Kikuchi had a bright idea to get around the lack of information
18:26he realized that security cameras in convenience stores would have recorded the movements of items of furniture
18:32especially anything on wheels
18:34this is a film from a convenience store which is located on the southern side of the fault line
18:41first this person noticed a vertical shake from the earthquake
18:46then the big horizontal movements came
18:49and then the movements in other directions
18:52these third movements reflect the movement of the fault
18:56the two men notice something is wrong
18:58that's the first small shock wave
19:02then this trolley on wheels tries to stay where it is while all else around it moves
19:08the place it goes to shows the direction of ground motion
19:12the professor applied the analysis to moving objects in other stores
19:30then he studied the contents of the NHK studio
19:33here's a person sleeping
19:35he wakes up when the vertical movement hits
19:37now look at the movement of this chair
19:40then there is the cabinet which moves out into the room
19:52I thought they might show the way the fault had moved
19:56plotting all this information on a map revealed the position of the fault
20:01it was not the same as the one already known to geologists
20:08another similarity with Northridge
20:12the morning of the earthquake
20:14we went up in a helicopter to try to find surface rupture
20:17which helps us greatly in understanding which fault broke in the earthquake
20:21which we were trying to determine the day of the earthquake
20:23they spent several hours flying around the epicentral area
20:26looking for the surface rupture
20:27they couldn't find it
20:30it's one of those unfortunate instances where we had to have an earthquake
20:34to find out where the fault that broke in the earthquake was
20:37we didn't know that the fault that broke in the Northridge earthquake existed before the earthquake
20:42later computer analysis from seismometers showed how the crack in the rock had migrated upward
20:47then it just faded out before it got to the surface making it invisible to geologists
20:55they have recently calculated that there are blind faults like this all over the Los Angeles basin
21:04guessing which one will produce the next earthquake is virtually impossible
21:08oh my gosh
21:10the only certainty about a big earthquake is that smaller quakes will follow
21:16okay, come on back, come on back, come on
21:18scientists swarmed over the area around Northridge and recorded the inevitable aftershocks
21:26clustered around the original epicenter they could be plotted in three dimensions
21:30this is the San Fernando Valley in there and this is the main part of Los Angeles with the Santa Monica Mountains in between
21:41and the earthquake occurred in this area we'll be able to see below the surface of the earth now
21:47tilting up looking from the south and you can see here's the earthquake started here and actually
21:53proceeded up the fault plane from the bottom to the top we'll rotate this around by 90 degrees and look at the fault plane from side on
22:05and you will be able to see the earthquakes lining up on the fault plane so it started at the bottom ruptured up to the top
22:14and this area up here to the north is the area that received the very strongest shaking
22:20and Los Angeles in this case is off in this direction so it did not receive the strongest shaking
22:27the strongest shaking occurred in the mountains or in the northern part of the San Fernando Valley
22:32but the main part of the city over here was spared from the strongest shaking
22:36however in the case of the Kobe earthquake the fault went right through the city the rupture was directed towards the city
22:45and very heavy shaking occurred right in the city in fact the shaking in Kobe was very comparable to the shaking in the northern part of the San Fernando Valley
22:59so in many instances the earthquakes had very similar ground motions but one very major difference is there were large buildings above the Kobe earthquake that were not above the Northridge earthquake
23:11there is a saying that earthquakes do not kill people buildings do
23:25in Northridge disaster struck one of the few large complexes that had been built there
23:30Northridge Meadows was a three-story apartment complex the first floor collapsed and the second floor pancaked onto the ground
23:43sixteen people died here
23:45but there were survivors
24:00wait wait wait wait wait wait wait hold up hold up
24:02you underneath that?
24:04okay he's right underneath here
24:06and I went to sit up to get up
24:08and I realized the ceiling was on my head
24:11I climbed down the balcony
24:13I grabbed my wife
24:15ran like heck to the center of the complex
24:17and I was wedged between my mattress and the wall
24:20and the mattress was up in the air
24:23and I couldn't figure out what it was doing there
24:26why I couldn't push it back down
24:29I was thrown around on my bed
24:32the lights went out
24:33it was black
24:35it was so dark
24:37I was very frightened
24:39I thought hell had opened up
24:41and came to take me
24:43I was convinced that I was going to die
24:46we got one more spot in the kitchen that we need to cut a couple of boards
24:50we have a chainsaw
24:52this was only one suburban building
24:55and it required a major rescue operation
24:58one of the rescuers also visited Kobe
25:00and was able to make alarming comparisons with Los Angeles
25:06in Kobe and Northridge
25:08earthquakes both
25:10we were very lucky in that the quakes occurred in early morning hours
25:13before people were in the office buildings and schools and commercial buildings
25:16that saved a lot of lives right there
25:18we have to consider that in Los Angeles and United States
25:21what happened in Kobe was they had large commercial buildings
25:25government buildings, high rises, collapse completely into the street
25:28or collapse two or three floors in the midsection
25:32the same thing could happen here in Los Angeles County
25:35a midday earthquake with people in those kind of buildings working
25:38we are going to be faced with many many live people trapped in massive building collapses
25:44this whole building in Kobe made of concrete
25:48collapsed backwards like a house of cards
25:51there are plenty of buildings like this in Los Angeles
25:54as at Northridge Meadows
25:57as at Northridge Meadows
25:59Kobe rescuers found themselves searching under buildings that had simply pancaked
26:02okay
26:03okay
26:04okay
26:05okay
26:06okay
26:07okay
26:08okay
26:09okay
26:10okay
26:11okay
26:12okay
26:14usually it was caused by the failure of the first floor
26:18buildings just knelt on the ground
26:21the problem was open spaces
26:23hotel lobbies restaurants shop fronts with wide space for displays
26:27and especially buildings with garages underneath
26:31often there would be a soft story halfway up the building
26:35in this one the third story has pancaked
26:39a whole building has a natural frequency
26:44and if that is matched by the frequency of shaking in an earthquake
26:47it can crack like a wine glass and collapse
26:57in such collapses there are few survivors
27:04in Kobe people live and work close together
27:07it is densely populated
27:09unlike Northridge but not so different from cities like Los Angeles
27:13we are looking at a map of the Los Angeles region
27:16which is centered on the San Fernando Valley
27:18this large urbanized area here
27:20in the case of the Northridge earthquake
27:23the earthquake actually broke to the north
27:25so that the strong shaking was directed away from the city
27:28into these relatively lightly populated areas
27:32to the north of Los Angeles
27:34so let's now take a look at the Kobe area
27:37and we are looking at a map that is on the same scale
27:39as the Los Angeles map
27:42one difference you can see immediately
27:44is that the area that is urbanized
27:46is very small by comparison
27:48a million people live in this little corridor
27:50and so the density of housing was much higher
27:53there were many more opportunities for the earthquake
27:55to knock buildings down
28:00but Kobe showed that it is possible to build for earthquake protection
28:04this market was still operating during the day of the quake
28:10feeding the homeless survivors
28:12while all around it was in ruins
28:14it sustained only light damage
28:21we knew the foundation of this area was not firm
28:24so we put many piles underneath to secure the building in the arcade
28:28we made it twice or three times stronger than normal
28:34this earthquake proved our decision was right
28:39now we shop owners and residents are glad of our decision at that time
28:44we know how to build buildings well enough now
28:49we know how to build buildings well enough now
28:51we are beginning to understand how to identify the areas that are
28:54most likely going to be damaged by earthquakes in the future
28:57and if we apply those building standards in the areas where they are needed
29:01we should be able to survive most earthquakes without loss of life
29:05with older buildings reinforcement with steel is enough to withstand most earthquakes
29:13new buildings are already constructed to the latest earthquake codes
29:16the lesson from Kobe is clear
29:20strong or reinforced buildings are less likely to kill
29:28but it was not just buildings that fell down
29:31one of the astonishing television images
29:35was the site of the Hanshin Expressway lying on its side
29:38the collapse took its toll
29:46but some survived
29:50it was much scarier to see the road weaving than to feel the ground shaking
29:57I thought the quake was over
30:00but then I felt as if my body was being pushed into the ground
30:03two or three seconds later I heard a huge bang
30:10then it was all over
30:13luckiest of all were passengers in a ski tour bus returning from the mountains
30:20I was driving the tour bus filled with passengers
30:30I felt I must stop
30:32I shut my eyes after we stopped
30:35when I opened them again
30:37the highway had just fallen away in front of us
30:40and the bus was swinging over the edge
30:42the passengers climbed out of the back of the bus to safety
30:53after Northridge
30:55eleven freeways came down all over Los Angeles
31:00significantly
31:02it was only those that had not been strengthened for earthquakes that fell
31:05in Kobe it was the same
31:09concrete shattered
31:11but only on those pillars that had not been fitted with a full metal jacket
31:16another clear message from both quakes
31:19in the future
31:21no freeway bridge should fall
31:27most of Kobe's modern bridges stood up to the intense shaking
31:32but the docks were almost completely destroyed
31:35Kobe was the biggest port in Japan
31:38with over 200 wharves handling most of Japan's export trade
31:42the earthquake of January 17th left them with just three
31:48the stoppage affected the whole Japanese economy
31:51the stoppage affected the whole Japanese economy
31:53the stoppage affected the whole Japanese economy
31:57as well as the US computer industry and Boeing in Seattle
32:04Japan's lost shipping trade was quickly picked up by Taiwan and Korea
32:15another cause of the damage was the types of soils that the city is built on
32:21they're somewhat softer than those in Northridge
32:23and in particular some of the made land areas
32:27in the port are places where liquefaction happened
32:30the ground was actually shaken so hard that it flowed
32:32and that was the major contributor to the serious economic damage in the port areas
32:37soft soil actually amplifies shock waves
32:42it makes the ground movement larger than it would be on hard soil
32:46tests have shown that soil becomes like a thick liquid when it's vibrated
32:50water which is thinner and lighter rises to the top
32:54anything heavy either sinks immediately
32:57or floats about before sinking more slowly like a waterlogged boat
33:01this liquefaction is exactly what happened to the Kobe docks
33:11as soon as the shaking stopped
33:14the ground re-solidified
33:16but the damage was done
33:18even in these extreme conditions
33:22some dockside high-rises survived remarkably well with only slight damage
33:28the reason is that their foundations were long and deep
33:32reaching down to the bedrock below
33:33Kobe's port is being reconstructed as quickly as possible
33:43Japan cannot afford to have this happen again
33:46the soil is being compacted firmly
33:49and the new foundations are going all the way down to solid rock
33:52further along the harbor
34:06a bridge was being built to the offshore island of Awaji
34:09the epicenter of the quake was directly under the bridge
34:14it didn't fall
34:17but the ground moved so much
34:20that the whole island has shifted slightly
34:23away from the mainland
34:25the bridge will now have to be one meter longer
34:29teacher Makiko Yoshihara lives near the bridge
34:34despite the fact that we live close to Awaji Island where the epicenter was
34:38we didn't suffer as much damage as the Hyogo prefecture or Nagata
34:46it was terrible there
34:49this curious anomaly illustrates an effect that has been puzzling seismologists
34:56when Makiko got to her school she was happy to find it still standing
35:01though considerably damaged
35:03but the area next to it had been devastated
35:06different parts of Kobe suffered different levels of earth shaking
35:13why was one area shaken into ruins and another left standing
35:19a Japanese seismologist Professor Irokura has a theory that would explain the mystery
35:26it concerns the waves that flow out in all directions from the epicenter
35:31a geographical description of Kobe
35:34is that there are mountains on the northern side
35:38and a sedimentary basin to the south
35:41it is rather like this pond
35:44and the banks surrounding it
35:46the basin contains alluvium very soft soil
35:49which is like the water in the pond
35:51when the waves from the earthquake reach the edge of the basin
35:55they ripple back making new waves going in a different direction
35:58we call them Banshi Sesiha or Basin Originated Waves
36:10waves flowing through the sedimentary soil in the basin
36:14are reflected back off the sides
36:17where they intersect with other waves
36:19they increase the surface movements in irregular patterns of peaks and troughs
36:28Kobe lies in a thin strip of land enclosed by the mountains and the sea
36:34earthquake waves bouncing off the mountains
36:38met the incoming waves and created peaks of damage scattered through the city
36:43large modern cities can be struck down in a matter of seconds
36:51this could be Los Angeles, San Francisco, Tokyo, or any city close to a plate boundary
37:07on the night of the quake
37:10300,000 people became homeless
37:13in addition to the 5,400 who died
37:17180,000 buildings were destroyed
37:231 million people were without food and without water
37:26the cost in cash
37:32was 147 billion dollars
37:37the problem cannot be ignored
37:46Tokyo has been preparing for years
37:49this is where the next major urban earthquake was expected
37:52not Kobe
37:5512 million people live in Tokyo compared to Kobe's one and a half
38:00Tokyo Metropolitan Government has a permanent staff on standby
38:07they are trained and equipped to respond rapidly in an earthquake
38:10one lesson learned from Kobe was that emergency supplies cannot be stored centrally
38:24they simply won't get through
38:26from now on emergency rations will be stored in all schools and community centers throughout Japan
38:32and local emergency water supplies are being reorganized
38:36so that they will never run out again
38:40the new philosophy being applied by planners, builders and rescue services
38:46is that an earthquake need not be a disaster
38:49crucial to this effort will be the work of seismologists
38:53in this science museum, Tokyo residents can experience an earthquake themselves
39:01they are put into rooms which are programmed to reflect the seismic waves of earthquakes
39:15they experience the vertical jolting first
39:19this is the primary or P wave
39:23then come the big horizontal secondary or S waves
39:27the shaking lasts as long as Kobe did
39:47knowing what it feels like to go through an earthquake
39:52helps dispel fear
39:53the difference between P and S waves is proving crucial to seismologists
40:00buried in the hills above Berkeley California
40:04are highly sensitive seismometers that might one day save many lives
40:09we want to get away from disturbances other than earthquakes as much as possible
40:15and in particular disturbances such as wind
40:17that pushes on the mountains and simulates earthquake motions
40:23and also from cultural noise, trucks going by and such
40:27these large Swiss made seismometers are expensive
40:31not many have yet been deployed
40:33they pick up the traces of every shock wave in the finest detail
40:38we see a succession of waves that come in and are recorded in these instruments
40:42and from analyzing the arrival times of these waves
40:46their amplitudes, their shapes, whether they are long waves or short waves
40:50we can learn a lot about where the earthquake happened exactly
40:54how big it was and then also how the rupture proceeded
40:59big as they are, these thoroughbreds are too delicate to catch the peaks of the strongest earthquake motions
41:04without going off scale
41:07so a tougher, cheaper workhorse of a seismometer is placed alongside
41:13this black box comes into its own only when a strong motion strikes
41:18we have an instrument on the floor here, a strong motion instrument
41:22and if we give it a good stamp
41:24then in a couple of seconds the P wave, if you will, will come up on the screen
41:29and there it is
41:31this is the primary wave
41:34it travels fast and it is that first vertical jolt that people feel
41:39so if you know a little bit about seismology
41:42you could create a pretty good looking earthquake
41:44and if I hit it
41:46in an earthquake, the shaking ground always moves the seismometer in a characteristic pattern
41:51and you can see here, this was the P wave
41:55this is the S wave coming in afterward
41:57these secondary waves which do the damage
42:01travel more slowly
42:03in fact, because we can pick up waves that travel faster than others
42:10and the first wave that arrives is not the most destructive one
42:13we hope by being able to catch that wave quickly
42:17broadcast this information even before most of the damage is done
42:21we hope to be able to do this really immediately as the earthquake happens
42:27as opposed to even a few minutes later like we are doing today
42:31it has been recognized for some time that if one has seismometers near where an earthquake begins
42:37that you can send information that the earthquake has started to areas that will eventually be shaken when the waves travel to them
42:43the waves travel to them
42:45the waves travel at about 2 miles per second and the radio waves basically travel instantly
42:50so you have the radio waves out running the seismic waves
42:56an early warning system based on P waves is already in use
43:00the Kobe quake damaged the track of the Shinkansen high-speed bullet trains
43:04had the trains been running they would have risked going straight into the damaged track
43:10it would have meant certain death for the passengers
43:17but Japan Rail has its own network of seismometers placed at some distance from their high-speed track
43:23as soon as the first shock wave from a big earthquake the P wave is detected
43:32all the Shinkansen trains are brought to a stop
43:35the local trains travelling more slowly are brought to a halt when the violent S waves arrive
43:50the Kobe quake struck just before the train started in the morning
44:03half an hour later and the system would have been put to the test
44:11in 1989 a warning system did save lives
44:14the Nimitz freeway in Oakland had collapsed during the Loma create-a-quake
44:24seismologists monitoring expected aftershocks were able to give rescuers 25 seconds warning
44:31before a magnitude 5 shock hit them
44:33they had time to get safely off the damaged structure
44:49different information could be gathered from the S waves
44:52using tiny seismometers from a surprising source
44:55what these are
44:59are little solid state accelerometers
45:02that have been developed for automobile airbag technology
45:05so that when your car suddenly decelerates
45:08they trigger the airbag
45:10these things are not very sensitive at all
45:13they're very inexpensive and so we can put them out
45:16in urban areas in lots of places where there's
45:19trucks rolling by lots of ground noise
45:20and still record the earthquakes
45:23the really big shaking that damages buildings
45:26we're hoping to develop maybe
45:28and deploy maybe 1,500 of them throughout the Bay Area
45:32to measure the ground motions in the places where people actually live and work during earthquakes
45:37they would be cheap enough to install all over California
45:42one of their first uses would be to help prevent fires
45:46in both Northridge and in Kobe
45:51many gas mains and domestic pipelines ignited
45:55Tokyo Gas already has its own network of seismometers
46:03they are closely spaced and cover only the Tokyo district
46:09the engineers know the soil conditions in which their pipelines are buried
46:19when the S waves hit their seismometers
46:22they will be able to calculate rapidly which pipelines have been damaged
46:26they can then prevent or stop roaring street fires
46:32by cutting off the gas from different parts of the city
46:34but that's not enough
46:42there could still be gas in pipelines which could flow into individual homes
46:47and ignite there
46:54so Tokyo households can now be supplied with new gas meters
46:58known as smart meters
47:01they will cut off the gas to the house as soon as the shaking reaches a certain level
47:11in Northridge as in Kobe
47:14the firefighters encountered major difficulties
47:17there is a real fear that in larger cities like Los Angeles or San Francisco
47:22it would be much worse
47:25we know that we're going to have to pay big attention to firefighting
47:30in an earthquake
47:32it's going to be a fight between going after people trapped in buildings
47:35and trying to put the fires out
47:37as you saw in Kobe even with cool damp weather
47:40they had massive fire spread
47:42massive firestorms
47:44and with Southern California's weather patterns
47:46if a quake like that were to strike during hot dry Santa Ana winds that are blowing 60 or 70 miles per hour
47:54the kind of conditions that cause our wildland conflagrations
47:58we could potentially have conflagrations in the city like that
48:02so we need to start looking at how we're going to dump firefighting resources into the city
48:07how we're going to get water when our water mains are broken
48:10possible big time use of firefighting water dropping helicopters in the city
48:16so for the emergency services
48:20rapid information about ground motion is crucial
48:23the lack of seismic information in Northridge
48:26meant they did not know exactly where to go
48:29one of the most difficult things to do
48:33is to know where to begin to look for the most likely damage
48:36we weren't quite there on the morning of January 17th, 1994
48:41we could tell that we should be looking in the Santa Monica area
48:46or in the San Fernando Valley area
48:49but we think it's a very small step given the capabilities we now have
48:53to actually being able to begin to assign emergency resources
48:57essentially on the basis of computer simulations
49:01and modeling of what we think will happen
49:03this is the power and natural gas
49:07a team of software engineers is designing a new computer system
49:10to take instant seismic data and superimpose it onto existing maps
49:15roads, gas pipelines, housing, population densities, even language groupings
49:22the system will then estimate where the damage will be in a matter of seconds
49:27we'll probably make it to the airport in about 20 minutes
49:30this information can be taken out into the field by search and rescue teams
49:35in their laptop computers
49:41their maps could show them not only which street to go to
49:44and which buildings are likely to have collapsed
49:47but could include current helicopter pictures of the damaged area
49:50in some circumstances they could be told which desk a person was sitting at
49:58when the earthquake started
50:04special urban search and rescue teams have been formed in California
50:08as a result of experience gained in the recent earthquakes
50:11they can bypass the telephone network and transmit the seismologist's information
50:19directly into their computers on site
50:22the speed of the response is absolutely essential
50:32if you don't perform well in the first few hours of a major earthquake
50:36it will be extremely difficult
50:408, 12, 24 hours down line
50:43to make up for what you didn't do during those first few hours
50:46so what will happen in those first few hours of the next earthquake?
50:52what should happen if the knowledge we already have were applied?
50:58some of the future is already here
51:01control rooms are being set up as if ready for a space flight
51:07or a war
51:09a P-wave is recorded and instantly broadcast
51:15size, location and direction of the quake is calculated within 5 seconds
51:20an early warning is put out on all radio stations
51:23and sirens are sounded
51:24there is time to take cover
51:30remember
51:32there is time for utility companies to stand by
51:35then the s-waves hit
51:37urban search and rescue teams have been alerted
51:51this time they know exactly where to go
51:55operations rooms are staffed and information is beginning to flow
52:00begin the operational briefing now
52:02logistics, this health service is going to need some support in transporting patients
52:06are you going to be able to handle that?
52:08we think we can probably deploy up to 3-4
52:10gas and power lines have been cut off
52:12we need to coordinate as quickly as we can because those numbers may be much larger than what we've got right now
52:20inevitably, some fires do break out
52:25none of the freeway bridges are down, but some older buildings have collapsed
52:35rescue teams arrive within minutes
52:38rescue teams arrive within minutes
52:44ok, let's go ahead and pull off, let's get the dog team in
52:48ok, canines
52:54ok, go ahead and get them
52:55ok, let's get them
53:16hello, is there anyone there?
53:18can you hear me?
53:20hello, can you hear me?
53:21he's alive
53:30rapid information can save lives
53:36from new seismometers to the latest rescue equipment
53:40the means are available to prevent even a major earthquake
53:44from becoming a disaster
53:46but the systems are not yet in place
53:49either in California or Japan
53:51a catastrophe like Kobe is waiting to happen again
53:56it could be avoided
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56:00Next time on Nova, James Randi, magician and investigator of psychic phenomena.
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