International Committee on issues of Global Changes of the Geological Environment, “GEOCHANGE”

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GEOCHANGE: Problems of Global Changes of the Geological Environment. Vol.1, London, 2010,  ISSN 2218-5798

Chapter 3.



Sumatra island tsunami of 26 December 2004


Tsunami examples

On December 26, 2004 monstrous tsunami waves struck the coasts of Sumatra island, Bangladesh, India, Malaysia, Myanmar, Thailand, Singapore, Maldives, and other territories bordering the Indian Ocean, affecting 14 countries in total. The tsunami was triggered by a very powerful magnitude 9.1-9.3 earthquake with an epicenter off the west coast of Sumatra, Indonesia. The tsunami and earthquake caused the deaths of 230,000 people. This event was one of the most terrible catastrophes in human history.

Tsunami aftermath on Sumatra Island, 24 December 2004

(Photo by U.S. Department of Defense)

Sumatra island tsunami, 26 December 2004

The Severo-Kurilsk tsunami took place on November 5, 1952 around 5:00 a.m. It caused the destruction of several settlements in the Sakhalin and Kamchatka regions. The tsunami was triggered by a powerful earthquake with a magnitude up to 9, which occurred in the Pacific Ocean an hour earlier, some 130 kilometers off the coast of Kamchatka. Three waves 15-18 meters high (according to different sources) devastated the town of Severo-Kurilsk and damaged a number of other settlements. According to official figures, 2,336 people were killed. The Severo-Kurilsk population before the tragedy was about six thousand people.

 Other very large, tsunami-triggering earthquakes occurred in 1964 (Alaska, M 9.2), 1868 (Peru, Nazca Plate, and South American Plate), 1827 (Colombia, Nazca Plate, and South American Plate), 1812 (Venezuela, Caribbean Basin of La-Plata, and South American Plate), and 1700 (Cascadia Earthquake, western U.S. and Canada, Juan de Fuca Plate, and North American Plate).

 Tsunami is a Japanese word meaning a harbor wave. Tsunamis occur primarily as a result of strong earthquakes or other tectonic processes such as landslides or explosions of volcanic islands. Tsunamis can also be generated by nuclear explosions in the water.

The most tsunami prone areas include: Japan; Kamchatka; Sakhalin; Kuril Islands; Aleutian Islands; Alaska; Hawaii; west coast of South America, U.S. and Canada; east coast of Canada; New Zealand; Australia; French Polynesia; Puerto Rico; Virgin Islands; Dominican Republic; Costa Rica; Azores; Portugal; Italy; Sicily; Aegean, Adriatic and Ionian coasts; Greece; African coast of eastern Mediterranean; Indonesia and Philippines. The scope of damage caused by tsunamis varies for different locations (T. S. Murty, 1981).

According to the general classification, tsunamis are long waves. Their length ranges from a few hundred meters to 600-700 meters, typically with 1 meter amplitude over the deep part of the ocean. The waves propagate in proportion to the square root of water depth. In the ocean, this rate can vary from a few hundred km to 700-800 km per hour. Upon reaching the continental shelf, tsunami wave decelerates and becomes higher. The ebb tide often preceded by short-period low amplitude water level fluctuations called precursors sometimes accompanies tsunamis as they approach the coast.

To ensure reliability of the statistical research, we used two independent catalogues, namely the International Tsunami Information Center (ITIC) catalogue ( and the database directory of the Intergovernmental Oceanographic Commission and the Russian Academy of Sciences (Historical Tsunami Database for World Ocean, HTDB/WLD,

The International Tsunami Information Center (ITIC) data-based statistical analysis of tsunami dynamics has made it possible to investigate the tsunami activity evolution during the last hundred years. The most comprehensive tsunami statistics given in that catalogue is that starting from 1990. The earlier data is incomplete. Therefore, when analyzing ITIC directory data, the research period was divided into two parts: a statistically more reliable period (1990-2009) and a less reliable period (1910-1990).

Fig. 15. Graph showing number of large tsunamis from 1990 to 2009

(by E. Khalilov, 2010, according to International Tsunami Information Center data)

Annual number of tsunami graph is marked in blue;
Straight-line trend is marked in red.

Fig.15 contains a graph for tsunami rate dynamics between 1990 and 2009. Two tsunami activity cycles stand out in the graph, with peaks in 2004 and 2007. Each cycle’s period is three years. The straight-line trend indicates a persistent tendency of significant increase in the number of tsunamis in the last decade.

Fig. 16 provides a graph for tsunami dynamics over the historical period of time between 1900 and 2009, according to the ITIC data. The polynomial trend of the fifth degree indicates the tendency for significant increase in the tsunami activity from 1990, and also the existence of three major cycles of increased activity of large tsunamis: 1920-1940, 1941-1980, 1981-present. At the same time, the straight-line trend displayed in Fig. 17 points to a steady increase in the annual numbers of catastrophic tsunamis.

Fig. 16. Graph and polynomial trend for numbers of large tsunamis from 1900 to 2009

(by E. Khalilov, 2010, according to International Tsunami Information Center data)

Annual number of tsunami graph is marked in blue;
Polynomial trend of sixth degree is marked in red.

Fig. 17. Graph and straight-line trend for numbers of large tsunamis from 1900 to 2009
(by E. Khalilov, 2010, according to International Tsunami Information Center data)
Annual number of tsunami graph is marked in blue;
Straight-line trend is marked in red.

Despite the fact that the tsunami statistics for the period from 1900 to 1990 may be incomplete, it nevertheless represents information about the most significant tsunamis that has survived in historical and scientific sources.

 The most complete tsunami data can be found in the databases of the Intergovernmental Oceanographic Commission and the Russian Academy of Sciences (Historical Tsunami Database for World Ocean; the HTDB/WLD is maintained by the Novosibirsk Tsunami Laboratory (NTL), which is part of the Institute of Computational Mathematics and Mathematical Geophysics of the Siberian Division of the Russian Academy of Sciences, This catalogue contains data pertaining not only to catastrophic tsunamis, but also to medium-sized and weak tsunamis ever documented in various national and international scientific and historical sources.

 The extremely large number of tsunamis is explained by the fact that a tsunami wave triggered by a strong earthquake can be registered in different countries with each entry taken for an individual tsunami. This is an absolutely correct attitude since the concept of tsunami wave implies emergence of coastal waves in specific areas. At the same time, there are occasions when a wave caused even by a strong earthquake takes the form of tsunami in one country only. In other cases, a strong earthquake-triggered wave can cause tsunamis in several countries as it happened during the powerful Indonesian earthquake of December 26, 2004, when the tsunami caused by the earthquake-triggered wave struck the coasts of dozens of countries, resulting in a huge death toll in 14 countries.

 Of great interest are the results of a statistical data analysis of dynamics of all documented tsunamis (strong, medium-sized, and weak) from 1800 to 2007. Such a long time span is selected in order to study possible cyclicity of tsunami manifestations.

To process the data correctly, we examined various time intervals with different scopes of tsunami-related information. It is clear that the more ancient the period we deal with, the more devastating are the tsunamis mentioned within it. Since, for the earlier period of history, only information about very large-scale events described in historical chronicles and recorded in various documents could have managed to reach us, graphs were drawn for the periods from 1800 to 2007 and from 1900 to 2007. Fig.18 contains a graph for the number of all tsunamis including medium-sized and weak tsunamis from 1800 to 2007, with a straight-line trend indicating a steady increase in the annual numbers of medium-sized and weak tsunamis. Fig.19 shows the same graph with a polynomial trend of the fifth degree. The polynomial trend allows identification of three cycles in tsunami manifestations: 1830 – 1890, 1900 – 1985, and 1986 to the present.

Comparing the graph for the dynamics of annual numbers of catastrophic tsunamis with the similar graph for all tsunamis including medium-sized and weak tsunamis allows a certain correlation between them to be established, Fig.20. The weak correlation refers to the period of high activity of medium-sized and weak tsunamis (1941-1970), whereas the high level of correlation covers the last tsunami activity cycle from 1995 to the present.

Fig. 18. Graph and straight-line trend for all tsunami numbers between 1800 and 2007
(by E. Khalilov, 2010, according to Historical Tsunami Database
for World Ocean HTDB/WLD data,
Annual tsunami numbers graph is marked in blue;
Straight-line trend is marked in red.

Fig. 19. Graph and polynomial trend for all tsunami numbers between 1800 and 2007

(by E. Khalilov, 2010, according to Historical Tsunami Database
for World Ocean HTDB/WLD data,
Annual tsunami numbers graph is marked in blue;
Polynomial trend of sixth degree is marked in red.

Fig. 20. Comparison of graphs for numbers of large tsunamis and of all tsunamis
from 1900 to 2007
(by E. Khalilov, 2010)
Annual numbers of large tsunamis graph is marked in yellow;

Annual numbers of all tsunamis graph is marked in azure;
High tsunami activity areas are marked in dark blue;

New Zealand tsunami, 15 July 2009

Thus, statistical study of the tsunami dynamics from ancient times to the present based on two independent databases enables us to conclude that there has been a substantial increase in the number of tsunamis in the last two decades. This tendency persists today as well.



Flooding in New Orleans after Hurricane Katrina, August 2005

Flooding in Nashville, Tennessee, U.S., 02 May 2010

Floods are one of the most severe natural disasters, usually affecting large areas. Unlike earthquakes, volcanic eruptions, and tsunamis, floods are not so instantaneous and have a longer period of manifestation.

 Floods have a number of features that make it harder for rescue agencies and state bodies to act properly during rescue operations and removal of the consequences. Typically, major floods lead to inundation of huge areas and total inaccessibility of the territory’s infrastructure including power lines, communications, means of conveyance, etc. Conventional ground vehicles cannot be used in affected areas, the fact which complicates the evacuation of people and the providing of disaster victims with emergency aid.

 In addition, the damage in flooded areas cannot be promptly assessed before the water level drops completely. All over the place, movement of people becomes limited and localized within small spaces such as rooftops, small hills, and other elevations. Unlike earthquakes and volcanic eruptions, major fires rarely accompany floods. What really represent a significant danger to people are power lines remaining underwater.

 Statistics for United States flood dynamics for the period between 1980 and 2008 reveals a significant increase in their numbers, with a faster growth of the number of floods from 1999 and from 2005 as shown in Fig. 21.

Fig. 21. 1980-2008 U.S. floods statistics

The general flood number trend points to a steady increase in the statistical values. The number of flood-related deaths depends directly on the scale of flooding.

Statistical analysis of the dynamics of U.S. flood-related deaths from 1913 to 2009 indicates the presence of a certain cyclicity in fatality numbers, which, in its turn, reflects the cyclicity in the number of floods (Fig. 22). The large cycles typically represent one or several catastrophic floods that have killed large numbers of people. Two types of cycles can be identified for the time span being considered: first-order cycles of very high amplitude with peaks in 1913, 1928, 1955, 1973, 2005, and 2009-2010, and second-order cycles with lower amplitude in 1922, 1935, and 1970.

Fig. 22. Diagram showing numbers of deaths during U.S. floods from 1910 to 2010.

(According to data from, with additions by E. Khalilov)
Annual numbers are marked in white;5-year average numbers are marked in green;
straight-line trend is marked in orange.

The largest number of flood-related deaths (about 1200 people) was witnessed in 2005. Note that people killed by the flooding during and after Hurricane Katrina in 2005 account for the majority of fatalities. In total, more than 1800 people died during the hurricane, most of them flood victims. The years of 2009 and early 2010, prior to late May inclusive, are characterized by a large number of major floods and related casualties.

Examples of major floods, 2010

May 2010 Flood in Azerbaijan

Early in May 2010, as a result of the Kura River overflowing its banks and incessant rains, 40 Azerbaijan rayons (administrative units) suffered inundation. The disaster led to the flooding of about 20,000 residences; more than 300 of them were destroyed and 2,000 were in hazardous condition; and 50,000 hectares of cultivated land went under water. 

Flood in Sabirabad Rayon, Azerbaijan, May 2010

The unusually high activity level of natural disasters as a result of heavy rains started to manifest itself across Azerbaijan from as early as the beginning of April 2010. April 5, 2010 saw a massive landslide on the Agsu Pass of the Shamakhy rayon, Azerbaijan. The ground sank along a nearly 30 meter long section of the Baku-Shamakhy-Yevlakh highway, significantly hindering road traffic. On April 10, 2010, large-scale landslides occurred in the mountain villages Urwa and Gulazi of the Gusar rayon of Azerbaijan, resulting in destruction of homes and extensive damage.


A massive landslide triggered by torrential rains took place in the Tovuz rayon of Azerbaijan on 27 April 2010; an entire private house sank underground, leaving five family members dead. Immediately thereafter, information about landslides and land subsidence started to arrive from different regions of Azerbaijan.

A study of the development of landslide processes in Azerbaijan showed that on May 3, 2010 Azerbaijan witnessed one of the world’s unique events, that is, simultaneous occurrence of large-scale landslides in seven rayons of Azerbaijan: the Balakan, Quba, Dashkesan, Goygol, Astara, Ismailly, and Lankaran rayons. These landslides destroyed many private houses and roads, causing great material damage.


The situation’s peculiarity owes to the fact that these areas are situated at the opposite ends of Azerbaijan, that is, in the north, south, west and north-east. Such a simultaneous large-scale manifestation of landslide phenomena within a vast territory that stretches across the whole of Azerbaijan can hardly be explained by only the heavy precipitation that falls there in large amounts every spring. Rather, intense large-scale tectonic processes in the Caucasus triggered the landslides. On 6 May 2010, a very large landslide took place in the Muganli village of the Shamakhy rayon of Azerbaijan (approximately 110 kilometers west of Baku) as a result of the continuing precipitation, leaving 15 of the village’s 180 houses in hazardous condition and forcing residents of five houses to be resettled. The roads leading to the village were blocked, and sown areas and orchards suffered great damage.


­ In recent years, the number of atmospheric phenomena-related natural cataclysms in Azerbaijan has increased dramatically. Again in 2009, heavy rainfall caused considerable damage to a number of Azerbaijani settlements. September 2009 saw the Dashkesan rayon in the country’s west affected by the disaster. The rainfall lasted for 45 minutes and was followed by hail that, according to witnesses, was as big as a chicken’s egg. On 23 May 2010, a similar phenomenon occurred during 40 minutes in the Goychay rayon of Azerbaijan.

Flooding in the U.S.

April 2010

On April 1, 2010 the U.S. northeast was hit by the largest flood in 200 years. Torrents of water washed away bridges and flooded the streets of many settlements. The state of Rhode Island suffered most of all. Due to the torrential rains that lasted for a whole month, the Pawtucket River overflowed its banks and flooded several districts in the town of Coventry. Many industrial plants were brought to a halt. U.S. President Barack Obama declared a state of emergency in Rhode Island. A section of the U.S. main east coast highway linking multiple states was closed. The Amtrak Company canceled several trains on the North-Eastern Railway.

May 2010

As a result of heavy rains on 01-02 May 2010, the state of Tennessee witnessed one of the largest floods in the region in the past 1000 years. Intense rains led to inundation of large areas in Arkansas, northern Mississippi, and southern Kentucky. Twenty deaths were reported in Tennessee. The flooding killed six people in northern Mississippi and another four in Kentucky

Tennessee floods, U.S., May 2010

On 7 May 2010, 30 Tennessee counties were declared major disaster areas by the federal government, with another 52 awaiting to receive that status. Combined, they cover approximately 31% of Tennessee which was the main disaster area. The damage from the floods is estimated at 1.5 billion dollars.

Flooding in Poland, May 2010

, Poland
, 22 May 2010

In the second half of May, large-scale floods spread all over Eastern Europe including Hungary, Czech Republic, Slovakia, and Poland. The situation in Poland was the most dangerous. An 8 thousand hectare territory was left under water and nearly 5 thousand local residents were evacuated. As of 25 May, 15 people had been killed by floods.

 The Vistula’s level in Warsaw exceeded its critical value by more than a meter. Several thousand residents were evacuated from eastern Czech Republic. According to the local authorities, people were evacuated from settlements located along the banks of the Odra, Olza, Ostravice, and Morava. Karviná, one of the largest cities in the region, was completely cut off from the outside world.

The Vistula’s level in Cracow exceeded the critical point. The authorities used helicopters and boats to relocate people from the natural disaster area. Residents of suburbs of the western Polish city of Wroclaw were hastily evacuated. According to tentative estimates, the Polish floods inflicted a loss of 2.5 billion Euros, as of 25 May 2010.


, 24 May 2010


Flood statistics  

A U.S. National Weather Service information-based analysis of statistical data on the damage inflicted by U.S. floods shows that between 1900 and 2000, there has been a steady increase in flood-caused loss, considering the inflation rate for 2007, Fig.23.

 Of great interest is the study of flood number statistics for the period between 2000 and 2010. It is this past decade that is notable for substantially increased geodynamic activity. One may wonder to what extent this pattern remains true for floods.

Fig.23. Economic damage from U.S. floods from 1900 to 2000

Annual values of damage from flooding are marked in blue;
Straight-line trend of damage from flooding is marked in red.

Fig. 24A contains a graph for the dynamics of numbers of flood notifications received worldwide from 2002 to May 12, 2010, according to the Global Flood Detection System, an experimental system aimed at providing flood disaster alerts ( A flood statistics analysis shows that since 2005, the number of floods has increased steadily, and this tendency has continued up to May 2010. The straight-line trend also indicates that.

Fig. 24B shows a detailed graph for the dynamics of worldwide-received flood alert numbers from 1 January 2010 to 12 May 2010. The graph is very specific about the sharply increased number of floods from February 2010 due to the seasonal growth of flood events. This can be clearly seen on the graph in Fig. 24A as well. Meanwhile, a comparison of numbers of seasonal floods (from February to June) for the same period in previous years reveals some constant dynamics of increase in the number of seasonal floods every year from 2005 to May 2010 inclusive.

Fig. 24. Dynamics of numbers of worldwide-detected flood reports

- is number of received reports between 2002 and 2010;
- is number of received reports between 01.01.2010 and 12.05.2010;




Analysis of the statistical indicators of natural disasters in the hydrosphere, exemplified by tsunamis and floods, proves the existence of a stable tendency for natural disasters in the planet’s aquatic environment to increase in number and scale. The straight-line trends of tsunamis and floods indicate this in particular.

Meanwhile, there is a sharp increase in statistical indicators and scale of manifestation of both tsunamis and floods over the last decade. The polynomial trends indicate a “surge” in the number of tsunamis and floods since 2000. This tendency persists today.

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