Category Archives: Earthquake

Day_138 : Natural Disasters in Europe (1)

Natural disasters in Europe mainly consist of hydrological, meteorological, climatological, earthquake and volcano eruption disasters.

europe-pic
Figure   The Europe

Earthquake disasters mainly occur in the Aegean Sea, the south-western coast of Balkan Peninsula, and the southern part of Italy. Volcanoes are active in the central and southern parts of Italy, the southern Aegean Sea, and Iceland area.

Concerning hydrological, meteorological, and climatological disasters, heavy rain and storm disasters are caused by low  pressure in the Icelandic area developed in the winter season. A cold atmospheric current coming from Arctic gains a warmer vapor stream from the Gulf Stream and develops a strong atmospheric depression in the area. This causes the strong winds and high tidal waves along the coastal areas of the North Sea.

Netherlands and England can be highlighted. The Netherlands had storm surges in 1530 and 1570. The death tolls were approximately 400,000 (1530) and 70,000 (1570) for each. The 1953 depression took an 1800-person death toll. This disaster also reached England. England’s disasters were the 1703 Thames river flood and the 2003 Heatwave. The temperature was 8–10 over the average year in August 2003.

With regard to earthquake disasters, Italy, Greece, and Portugal are the main countries to be affected.

The following past article explains the recent earthquake cases in Italy.

To be continued…

Day_76 : 1995 Kobe Earthquake victims

The 1995 Kobe earthquake taught us a lot of lessons. Today I am going to give you the following two questions:.
1) Why were there so many early 20s victims?
2) Which floor is more dangerous, 1st or 2nd?

1) Please look at the following picture. You can see the victims’ age distribution. Females and elderlies are more likely to be victimized because of their lack of physical strength. However, why did so many people in their early 20s die? Yes, they were university students. There are many universities in Kobe. Students tended to be less rich. They tended to stay on the 1st floor in cheaper wooden apartments.

kobe victims age distributions

2) You already know the answer. Of course, the first floor is more dangerous, especially in a wooden house. 1981 is the year in which the Japanese government set the building code. So the buildings, apartments, etc. built after the year tended not to be destroyed by the earthquake, including the Kobe earthquake.

1stfloorKobe

Photo: Dr.Takashi Inokuchi

We should learn the lessons from the disaster; this is the best thing we can do for the victims.

 

Day_112 : The 1923 Great Kanto Earthquake and Disaster Prevention Day(Tentative)

September 1 is Disaster Prevention Day in Japan. This is because of the 1923 Great Kanto Earthquake. This quake caused over 105,000 casualties and had huge impacts on Japanese society. The Great Kanto Earthquake is the worst disaster in Japanese history. Here, some points are picked up. First, the quake directly attacks the capital city, Tokyo. Second, the disaster killed so many people mainly by fire, not objects falling. Third, rumors made the disaster worse. Fourth, Tokyo has recovered first and strongly.
With regard to the devastated areas, Tokyo and Kanagawa (Yokohama) populated areas were severely affected by the quake. The epicenter was located near Oshima Island in Sagami Bay, south of Tokyo. In Yokohama, 90 percent of all homes were damaged or destroyed. 60 percent of the city’s population became homeless (Brown University).
Concerning the fire, the time at which the earthquake hit was 11:58, so the families had prepared for their lunches. Many families’ cooking stoves were overturned by the quake, causing fires. The fire spread out with strong winds.
In respect of the rumors, the rumors, especially about Koreans, such as “Koreans do criminal activities and cause social confusion,” make the disaster more political. The Home Ministry declared martial law and ordered all sectional police chiefs to make maintenance of order and security top priorities. After the disaster, the radio became popular all over Japan. This is because of the disaster’s lessons.
Concerning the recovery, Shinpei Goto, Mayor of Tokyo, created and proceeded with a reconstruction plan for Tokyo to rebuild better. The basic infrastructure of today’s Tokyo was built during that time. 

*Death numbers were revised after the recent research from over 140,000 to 105,000 because there were several double countings.

Day_195 : Scientists and Disaster Management Controversy issues with a L’Aquila Earthquake Case

The L’Aquila earthquake, which struck the Abruzzo region of Italy on April 6, 2009, was a significant case study for both scientists and disaster risk management professionals for several reasons. With a magnitude of 6.3, this earthquake caused extensive damage to the medieval city of L’Aquila, resulting in the deaths of more than 300 people, injuring over a thousand, and leaving tens of thousands of people homeless. Beyond the immediate physical damage and tragic loss of life, the L’Aquila earthquake raised important issues related to earthquake prediction, risk communication, and the responsibilities of scientists and authorities in disaster risk management.

Scientific Aspects and Controversies

The occurrence of earthquakes sparked a controversial debate over the ability to predict earthquakes and the communication of seismic risks to the public. Before the earthquake, a series of tremors were felt in the region, leading to heightened public concern. A week before the major earthquake, a meeting of the Major Risks Committee, which included government officials and scientists, was held to assess the situation. The committee concluded that it was not possible to predict whether a stronger earthquake would occur but reassured the public, suggesting a low likelihood of a major event. Unfortunately, the devastating earthquake struck shortly thereafter.

This situation has led to significant controversy, particularly regarding the role and communication strategies of scientists and government officials in disaster risk management. Critics argued that reassurances were misleading and contributed to a false sense of security among the population.

Legal and Ethical Issues

In a highly controversial decision, six Italian scientists and one government official were initially found guilty of manslaughter in 2012 for underestimating the risks and failing to adequately warn the population. This verdict was widely criticized by the international scientific community, which argued that it was unreasonable to expect scientists to accurately predict earthquakes. The verdict was largely overturned in 2014, with the convictions of scientists being annulled and the sentence of the government official being reduced.

Disaster Risk Management Implications

The L’Aquila earthquake underscored the importance of effective disaster-risk management and communication strategies. Key lessons include:

  1. Communication of Uncertainty: It highlighted the need for clear communication of scientific uncertainty to the public. Conveying the inherent uncertainties in earthquake prediction is crucial for helping individuals and communities make informed decisions about risk reduction and preparedness.
  2. Public Education and Preparedness: The tragedy reinforced the need for ongoing public education on disaster preparedness and the importance of building earthquake-resilient communities.
  3. Building Codes and Urban Planning: Ensuring strict adherence to earthquake-resistant building codes and urban planning practices is vital in reducing the vulnerability of buildings and infrastructure.
  4. Multi-disciplinary Approach: The event demonstrated the importance of a multi-disciplinary approach that includes not only seismologists but also engineers, urban planners, emergency management professionals, and policymakers in disaster risk management planning and response.
  5. Ethical Responsibilities: The aftermath raised questions about the ethical responsibilities of scientists and the balance between preventing public panic and ensuring preparedness.

The L’Aquila earthquake remains a case study of the complex interplay among science, policy, ethics, and public communication in the context of natural disaster risk management.

Day_193 : Plates and Earthquakes

Earthquakes are caused by the cracking of the plates of rock (bedrock) that lie beneath the earth. Over time, forces build up on these rock plates and eventually they break. The force produced at that time is felt as an earthquake. The main reason for the plates to break is the movement of several large plates that cover the earth. These plates cover the surface of the earth and come in various sizes and shapes. When these plates collide or pass each other, earthquakes are likely to occur.

The Pacific Rim Seismic Zone, which encircles the Pacific Ocean, and the Himalayan-Alpine Seismic Zone, which extends from Indonesia through the Himalayas to the Mediterranean Sea. Japan is in the Pacific Rim seismic zone, and earthquakes occur frequently because of the movement of multiple plates beneath the ground. Depending on how these plates move, large and small earthquakes occur. Large earthquakes are especially likely to occur near deep ocean bottoms (ocean trenches). As the plates move, forces build up on land, which can also cause earthquakes.

 

Day_153 : Reported Death Numbers

I will update a column of the NIED e-mail magazine which I wrote a long time ago because the content is not faded with time. (I will do this step by step in Japanese and English.) I will also add comments to update the situation.

Published February 4, 2010
NIED-DIL e-mail magazine: Reported fatalities due to disasters

January 12 There was a big earthquake in Haiti. The consequences are still a major social issue, but at an early stage, the President declared that the number of casualties reached 200,000.

At the time of the Hurricane Katrina disaster at the end of August 2005, the first report was 10,000 casualties. But, in the end, there were about 1,300. I felt that nationality, culture, and so on became apparent compared to Japan.

A typical case in Japan is the Great Hanshin-Awaji Earthquake. I was living in Kyoto and worked in Kyoto City at that time. I remember that around 7 a.m., it was reported on TV that there were only a few deaths. As time went by, it increased to hundreds and thousands.

The U.S. tends to have a top-down and strategic approach; on the other hand, Japan seeks bottom-up and accurate process to disclose the number. In the 2004 Indian Ocean tsunami, reported death tolls in affected countries fluctuated, but taking this into account is a way to understand the disasters that reflect the country’s situations, including social backgrounds, cultures, economies, and so on.

Regarding Haiti, the number of reported deaths increases with time. I pray that the number will not be so huge.

P.S.
For example, the following World Vision website considers the current estimated death to be 250,000. In short, the first report ended up gaining some meaning.

https://www.worldvision.org/disaster-relief-news-stories/2010-haiti-earthquake-facts

Day_123 : 1995 Kobe Earthquake victims (2)- Golden 72 hours

Day_76 gave you the following two inquiries on the 1995 Kobe earthquake:.
1) Why were so many early 20’s victims victimized?
2) Which floor is more dangerous, 1st or 2nd?

Day_76 : 1995 Kobe Earthquake victims

 

The next question is: what can you say about the following Figure 1?

rescue
Figure 1: Search & Rescue Operation Statistics

You can see the survival rate dramatically dropped after 3 days and 72 hours. The experts say this 72 hours after the disaster, especially earthquake, is golden 72 hours. This is a well-known phrase even before the Kobe earthquake.

Day_107 : Italy-Recent earthquake and past earthquake disasters

Below is the outline of the earthquake disaster in Italy from ADRC.
“A magnitude 6.2 quake hit at 03:36 (01:36 GMT) on April 24, 2016, 100km (65 miles) north-east of Rome, in central Italy. More than 70 people were killed in the earthquake.”

However, Reuters mentioned, “The death toll from a devastating earthquake in central Italy climbed to 250 on Thursday as rescue teams scoured mounds of rubble for a second day in towns and villages flattened by the natural disaster.” on Friday, two days after the quake.

In addition, the source also added, “Almost 200 of the victims died in Amatrice, which is famed for a local pasta dish and was full of holiday makers ahead of its 50th annual food festival, set for this weekend.”

Historically speaking, Italy has had a lot of earthquake disasters that have caused huge numbers casualties. Italy has had 44 earthquakes that have caused over 1,000 deaths since 1600. The interval is approximately . 25 years. They happened mostly in the central and southern part of Italy around the Apennine mountains and caused huge casualties. One of the reasons they had a large number of casualties was the stone-built houses.

Table 1 and Table 2 show the 1900–2016 top 10 deadliest and costliest disasters in Italy (EM-DAT).

Table 1: Total deaths
Italy deadliest

Table 2: Total damage
Italy costliest disasters

Southern Italy had an earthquake (M6.9) in Campania (1980 Irpinia earthquake), the dead number is approximately . 4700, damage is 20 billion USD. The 2009 L’Aquila earthquake (M6.3) occurred and caused approximately death and 2.5 billion USD damage. This earthquake became controversial because the scientists and government officers were sentenced to six years in prison for their false announcement. The quality of construction also became an issues “Once again, we are faced with a lack of control over the quality of construction.” “In California, an earthquake like this one would not have killed a single person,” Franco Barberi, who heads a committee assessing earthquake risks at Italy’s Civil Protection agency, told reporters in L’Aquila (Reuters AlertNet) after the quake.

1908 Messina earthquake (M7.1) had caused the highest death number (75,000) in Italian history since 1900.

Reuters said still now (26, 2016), “Italy has a poor record of rebuilding after quakes. About 8,300 people who were forced to leave their houses after a deadly earthquake in L’Aquila in 2009 are still living in temporary accommodation.”

 

Day_201 : Ground conditions are a fundamental factor in determining the amplification of seismic motions at the ground surface and the magnitude of earthquake damage

The condition of the ground is an important factor in determining how strongly an earthquake will be felt. For example, in the 1891 Nobi earthquake (Japan), the 1923 Kanto earthquake (Japan), and the 1985 Mexico earthquake (Mexico), the softer the ground, the stronger the earthquake shaking. Especially in softer strata, seismic waves are slower, so the shaking is greater. This shaking is further intensified when the period of the strata coincides with the period of the earthquake or building. This is called resonance and is the cause of many building failures.

For example, in the 1891 Nobi Earthquake in Japan, most houses near the epicenter were destroyed, but the number of houses destroyed decreased as one moved farther away from the epicenter. At a distance of 50 km from the epicenter, few houses were broken in areas with hard ground, while many were broken in areas with soft ground; in the 1923 Kanto earthquake in Japan, few houses were broken on the Yamanote plateau in Tokyo, while many were broken in the Arakawa lowlands; in the 1985 Mexico earthquake, the collapse of tall buildings in particular was observed, but this was also caused by soft ground.

The destruction of homes by earthquakes has a major impact on human casualties, fires, and even society as a whole. Therefore, when considering earthquake countermeasures, it is very important to carefully examine the condition of the ground.

Source URL:https://dil.bosai.go.jp/workshop/2006workshop/gakusyukai19.html

Day_184: Thorough Comprehension of Earthquakes

Analyzing the Origins of Earthquakes

Tectonic plate motion is the predominant catalyst for seismic activity on a global scale. The lithosphere, which comprises the outermost layer of the Earth, consists of numerous sizable tectonic plates that undergo gradual movement over extended periods. When these tectonic plates converge, they can cause immense levels of compression, resulting in seismic activity known as earthquakes. Volcanic eruptions can induce seismic events, just as human activities like drilling and mining can trigger earthquakes. The geographical coordinates and magnitude of an earthquake can also be affected by the composition and structure of the soil and rock in the vicinity.

Earthquake Classifications

Earthquakes can be classified into various categories, such as tectonic, volcanic, and human-induced earthquakes. Tectonic earthquakes result from the displacement of tectonic plates, whereas volcanic earthquakes arise from volcanic processes. Anthropogenic earthquakes are triggered by human activities such as mining and drilling. Earthquakes can exhibit varying levels of severity, ranging from minor shakes to extensive devastation.

Seismic Magnitude Scales

The seismic intensity of an earthquake is quantified using the Richter scale, which spans from 1 to 10. The Richter scale quantifies the magnitude of the seismic waves produced by an earthquake. As the magnitude increases, the amount of energy produced by the earthquake also increases. The Modified Mercalli Intensity Scale is an alternative scale employed for quantifying the intensity of an earthquake. The purpose of this scale is to assess the impact of an earthquake on individuals, structures, and the surrounding ecosystem.

Impacts of Earthquakes

Earthquakes can cause various impacts, which vary based on their magnitude and location. Minor seismic events may result in just minimal vibrations; however, more powerful seismic events can lead to extensive devastation, encompassing structural impairment to buildings, roads, and other essential infrastructure. Earthquakes have the potential to induce landslides, tsunamis, and other consequential phenomena, which can result in further destruction and casualties.

Earthquake Forecasting and Early Warning Systems

Notwithstanding the numerous technological improvements, earthquakes remain unpredictable and might occur at any given moment. Scientists have devised many techniques to forecast earthquakes, such as monitoring seismic activity and detecting alterations in the earth’s crust. Early warning systems can additionally offer crucial time for individuals to proactively respond prior to the occurrence of an earthquake, such as vacating structures and finding refuge.

Earthquakes of the past

Throughout the course of history, seismic activities have resulted in extensive devastation and significant loss of human lives. Notable earthquakes throughout history include the 1906 San Francisco earthquake, the 1960 Chile earthquake, and the 2011 Japan earthquake. These seismic events serve as a poignant reminder of the formidable potency of this natural occurrence and the significance of being well-prepared.