Evolution of Spreading Rumors in

Social Media: And Its Implication

to Social Risk Communication

June 27, 2013

IAMCR2013

Hiroshi YAMAGUCHI

Komazawa University

Explosion at Cosmo Oil

• LPG tanks exploded after the 3.11 Earthquake

• No official info provided due to confusion

• Rumor on “black rain” emerged

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Cosmo

Tokyo

Bay

Tokyo

Chiba

City

Ichihara

City

★

Twitter Data

• Great East Japan Earthquake Big Data

Workshop “Project 3.11”

• Obtained tweet data during the period

• Extracted 187,202 tweets quoting “Cosmo”

• Manually identified the rumor tweets

• Sorted as 4 Chains of rumor

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“Cosmo” Tweets

4

“Seed” Tweet (7 RTs)

• First chain of rumor

• Implied the solution

is toxic

• Instructed specific

actions

• Not so much diffused

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2011-03-11 18:00:26

Aqueous solution is floating

in the air due to the fire at

the Cosmo Refinery in

Ichihara. Do not touch the

rain. Put on a flu mask.

Shinkansen express trains will

not run today.

“Original” Tweet (1,700 RTs)

• Added a message to

raise awareness

• Referred to “rain”

• Area expanded to

Chiba

• Instructed more specific

actions

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2011-03-11 18:43:40 [plz RT]

[plz RT] Beware! Poisonous

substance by the explosion at

Cosmo Oil Refinery

contaminates clouds, and

falls with the rain. Those who

live near Chiba City should

bring your umbrella or oilcoat

when you go out. Do not

touch the rain!!!

“Quoting” Tweet (18,600 RTs)

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2011-03-11 20:46:55 RT

@XXXXX: [from mixi] Those

who live near Chiba City!

Poisonous substance by the

explosion at Cosmo Oil

Refinery contaminates clouds,

and falls with the rain. Bring

your umbrella or oilcoat

when you go out. Do not

touch the rain!!! Plz let

people know!!

• Quoting previous rumor

and added comments

• Referring to “mixi,”

the source of info

• Added a message to

expand the rumor

“Modified” Tweet (17,200 RTs)

• Modified to show the

source of information

to add credibility

• Area further expanded

to Tokyo

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2011-03-12 14:57:19

Personnel at Cosmo Oil

notified my acquaintance. For

those who live in Chiba and

other part of Tokyo

metropolitan area: the rain

contaminated with some

chemical substance due to

the explosion at Cosmo may

fall. It is really dangerous. Plz

use umbrella or oilcoat!

“Evolution” of the Rumor

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• 4 Chains of Rumor

– “Seed” Tweet

– “Original” Tweet

– “Quoting” Tweet

– “Modified” Tweet

They knew it might not be true

• People share rumors not

because they believe

– to feel ease

– To recover control on situation

– To contribute to community

10

2011-03-11 21:51:59

Not sure if it's true or

not, but for prevention:

Poisonous substance by

the explosion at Cosmo

Oil Refinery

contaminates clouds,

and falls with the rain.

Those who live near

Chiba City should bring

your umbrella or

oilcoat when you go

out. Do not touch the

rain.

“Vaccines” take time . . .

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• Info from trustworthy

source did not reach

people in the midst of

diffusion

NHK news reports

Lessons Learned

• Let them go and wait

– Do not try to suppress or eliminate

– Faster than mass media

– Let other users do

• Diffusion of rumors depends on architecture

– Power of open networks

– May need assistance for users of closed networks

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Rumor and Action to be Taken

• Trust related to the action

– Trust in info

– Trust in source

– Cost of action

• Tweet instructing

immediate evacuation from

National Diet member was

retweetd 700 times

13

011-03-11 17:20:13

Those who live nearby

should evacuate

immediately RT

@XXXXX : @XXXXX A

big explosion at Cosmo

Oil at Ichihara, Chiba

prefecture. Flame is

turned up!

http://twitpic.com/48e

em8

Activity-Based Trust Formation

• Hierarchy of effect model for social media era

• Information sharing to develop conviction

• Necessary level of conviction relies on the

“cost” of action

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Attention Interest Sharing Conviction Action

Cost of Actions Affect Trust?

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• Survey on 580 twitter users

• Asked how they evaluate info/how they act

based on different sources of info

• High cost action

require high

trustworthiness

Conclusion

• Analysis of a rumor in twitter revealed a

pattern like “evolution” of life

• Info flow in social media is faster than that

from mass media

• Potential of social risk communication

• Activity-Based Trust Formation Model needs

further research

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