Geological surveys to meet the needs of society

The first Japanese construction boom occurred 50 years ago, prior to the 1964 Olympics. Today, many buildings are in need of maintenance and upkeep. Since the Great Hanshin earthquake of 1995, many buildings have been retrofitted to reduce the impact of seismic activity. What is your take on the current state and demands of the Japanese construction market, and what is the importance of geological surveys in meeting those demands?

Following the reconstruction period after World War II, Japan experienced a high economic growth period until the early 1970s, during which a large number of civil engineering structures were built. Subsequently, economic growth began to decline, and the period of zero growth has continued until the present since the bursting of the bubble economy in the early 1990s. The civil engineering structures developed during the high economic growth period had been aged more than 50 years since their construction, and their deterioration had progressed. The Sasago Tunnel collapse in 2012 triggered a shift in emphasis on maintenance and management. Development of infrastructure has changed from new construction to maintenance and management of aging civil engineering structures.

In response to these changes in the social environment, the number of surveys, inspections, diagnostics, and designs for maintenance and management has increased compared to civil geological surveys of new construction projects, and the renewable energy field has also become active, therefore the content of our business has diversified. The aging of civil engineering structures is inevitable, but the policy has shifted from "corrective maintenance" in which repairs are conducted after the infrastructure is damaged, to "preventive maintenance" in which measures are taken to extend the life span of the infrastructure before it breaks down. In preventive maintenance, it is important to assess accurately the topographical and geological conditions at the time of construction and the maintenance management. On the other hand, Japan is located on a plate boundary, and its topography and geology are characterized by complexity and variety. For preventive maintenance, precise consideration for complex topographical and geological conditions is required, and our high-quality geological surveys are expected to satisfy such needs.

Japan has a rapidly aging and shrinking population, with a smaller pool of talented young graduates coming through universities and making it more difficult for companies to replace their older workers and pass on their knowledge to the next generation of engineers and workers. What impact has Japan’s demographic shift had on your business?

This is a major challenge not only for our company, but for the industry as a whole. It has made it very difficult to hand over our technology and knowledge to the next generation. If we take an overview of the industry, we can automate where possible. High-quality geological surveys and precise consideration are expected for complex and various topographical and geological conditions in Japan. Even if we take the alternative of introducing AI, it is essential to pass on the technology to the next generation. Natural conditions do not change with time, therefore it is a critical issue to maintain and pass on advanced technical skills based on an understanding and experience of the laws of nature. 

Your firm conducts geological surveys which can be divided into five main areas. The first is mountains, where you work with highways and tunnels. The second is plains and flatlands, where you work with river embankments and skyscrapers. The third is coastal regions, where you work on projects such as power plants and seawalls. You also work in seas, lakes, and marshes, as well as other areas. How are you able to cater to the needs of a diverse number of environments?

Our company’s biggest strength is that we can conduct investigations on both land and sea. Of course, there are some differences between the land and ocean investigations, however, we need to evaluate both seamlessly, and I think that we can provide that solution.  

For ocean construction, evaluating the characteristics of the seabed is extremely critical to ensure safe construction methods and Kawasaki Geological has been at the forefront of marine geotechnical investigations. For example, you have been conducting marine boring surveys and even developed autonomous underwater vehicles for highly accurate seafloor surveys. What are some of the challenges for marine geological surveys and how do your technologies overcome them?

Compared to land, marine investigations are not easy. There can be some complications in the operation of the investigation, and the weather also proves challenging. We started working on the marine survey business during a high economic growth period to respond to the needs of marine resource development in Japan. With our extensive experience in the field, we are safely able to conduct complex marine surveys.

Marine surveys include seismic profiling and AUV (Autonomous Underwater Vehicle) seabed surveys. In seismic profiling, artificially generated vibrations are reflected and diffracted from the seabed and strata boundaries below the seabed, and oscillatory waveforms are recorded by a receiver attached to a cable towing from the vessel at regular intervals. By analyzing the data, the topography of the seabed and the geology under the seabed are identified. Although this technology is not unique to our company, we specialize in interpreting acquired waveform recordings and analyzing the velocity layer structure with high precision.

As an example, we applied this technology to the delineation of Japan's continental shelf with a survey and analysis of the topography and geology of the seabed under the UN Convention on the Law of the Sea. A continental shelf is topographically defined as a relatively gentle slope of the seabed continuing from land, generally up to 200 nautical miles, and is known as an Exclusive Economic Zone (EZZ). The continental shelf is rich in biological and natural mineral resources, which coastal countries are entitled to extract or exploit on a preferential basis. On the other hand, if the continental shelf is recognized as being topographically and geologically connected to the land, it can be extended over 200 nautical miles, which is known as the extended continental shelf. In obtaining recognition, we must precisely show the distribution of topography and geology satisfying the conditions given as the criteria. The results of our technical expertise were approved by the United Nations, and as a consequence, we successfully expanded Japanese land by 310,000m2, increasing it by 80%. Recently, requests to our company for the survey of new energy resources instead of oil and other fossil fuels have been increasing. The marine survey technology that our predecessors have built up with challenges is making a significant contribution to society.

Sonic exploration using a ship

Maritime boring

Vehicle-towed ground penetrating radar exploration vehicle

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The reason for the high precision of the evaluation of velocity layer structure is the technique we used. In general, seismic exploration focuses on the initial motion captured by the receiver. In this case, tomographic analysis using the initial motion analysis as an initial model can provide mathematically reasonable results, but the results are often not consistent with the actual geological structure. To solve this problem, we applied the forward modeling method, which can read and interpret the data of subsequent waves recorded in the vibration waveform together with the initial motion and utilize such information by repeatedly modifying the model and processing calculations from the initial model building stage to obtain precise results. Many university researchers have studied the analysis of the subsequent waves; however, it has not been well commercialized in the industry yet. Only our company has commercialized this technology.

You have developed advanced technology utilizing muon particles which can conduct surveys at significant depths under the ground and they can also elucidate underground structures. Can you tell us more about your R&D strategy, and are there any particular products that you are working on that you would like to showcase to our international readers?

Our company has grown as a geological survey expert and we have developed our technologies to coincide with the needs of society. We also contribute other technologies besides marine survey technology to the society such as underground radar investigations which can detect underground cavities. This is a technology for estimating the underground cavities based on images of reflected waves from underground obtained by transmitting and receiving electromagnetic waves. There are various pipes buried under the road, and soil movement occurs due to groundwater flow caused by the aging of these pipes. Then, cavities are formed around the buried pipes. The cavities grow upward over time, and one day, all of a sudden, a road cave-in occurs. Pulse Radar exploration is generally used to detect cavities directly under the road  (within 50 cm to 100 cm), where these extremely hazardous conditions exist. On the other hand, the cause of the cavitation is often an aging buried pipe (sewage pipe) at a deep location. the CHIRP(Compressed High-Intensity Radiated Pulse) exploration which we owned is a technology capable of detecting deeper (3 to 5 m), and which concept is based on the preventive maintenance to find the deeper deformations that could lead to cave-ins. It is said that there are more than several thousand road cave-ins per year in Japan. Therefore, preventive maintenance is very important, and early detection of potential cavity growth allows for systematic repair of sewage pipes. We can also conduct continuous-wave laser exploration that allows probing to even greater depths (about 10 meters). Pulse and CHIRP radars are vehicle-mounted device types that can detect without restricting traffic on the road. Continuous-wave radar (step type) requires a step-change in the frequency of the signal to obtain information at depth and is not towed by a vehicle but is fixed to the road for a certain period to make measurements.

Is this CHIRP radar only being used domestically or are you using it in overseas markets too?

This technology has been used in the Middle Eastern region. This technology was shared in international academic meetings, and we were assigned to work. It was originally military technology, but there is a regulation to ban the export of military technology or technology that could be used by the military, so we cannot export that technology.

Given the technological success of this endeavor, are you looking for any new opportunities for such partnerships overseas?

There are two types of methodologies for marine investigations. one is using a drillship, and the other is setting up a scaffold in the sea to conduct borings. We do not own a drillship, so we collaborate with other companies to conduct surveys on each occasion. Since overseas suppliers have their drillships, I believe there are some opportunities to form partnerships with them in surveys using vessels. The same applies to offshore wind power generation.

We know that in 2014, you established your Hanoi office in Vietnam. You have also been providing geological surveys and technical support to infrastructure projects in developing countries like Vietnam and Mongolia. Moving forward, which countries or regions have you identified for further expansion, and what strategies will you employ?

Originally, our overseas surveys began with a pyramid archaeological project in Egypt. Later, we expanded our business to Mongolia and Vietnam, but we are open to any country or region as long as we can utilize our survey techniques, such as marine surveys. From the perspective of future economic development and infrastructure improvement,  Southeast Asia has the most potential.

Imagine we came back in six years for the 85^th anniversary of your company and have this interview all over again: what would you like to tell us? What are your dreams for this company, and what goals would you have accomplished by then?

Let me explain our motto and logo. We aim to be earth doctors. In this symbol, green represents the land and blue represents the sky. The heart in the middle represents the humans. Together with these three represents "TEN CHI JIN". The "TEN(heaven)", "CHI(earth)" and "JIN(man)" are the basic elements that form the world and represent the worldview of all creation (all things). Also, the curved shape represents the human eye. Overall, our logo shows we are earth doctors for all geographical and geological features such as oceans and lands. In the medical field, a doctor uses a variety of techniques to examine people's bodies, such as medical interviews, simple diagnostics, precision examinations, etc. We aim to examine and diagnose accurately the internal structures and conditions of a site by using specialized and advanced techniques. To understand or predict phenomena in nature, it is important to understand the phenomena occurring in the site correctly, which we call the "GENBASHUGI (hands-on approach)," and we call it our motto.

Although Japan is a small country, its topography and geology are complex and diverse, and its climatic conditions are also highly variable. It differs from continental geology, in which horizontal strata are spread out. Therefore, we conduct a geological survey at each site and interpretation based on the geology to lead an engineering evaluation. Moreover, we emphasize training personnel who can do such a survey.

Technologies have evolved, for example, 3D technologies have been available, and it is good to analyze data in 3D. It looks good, but the key is the certainty of the geologic model. In general, underground geology is estimated from the information obtained by limited points. The precision is very rough compared to the structures on the ground. Our mission is to conduct cost-effective geological surveys, analyze the obtained data precisely, and interpret and evaluate them in a geologically correct way following the rules of nature.