DigitSeis 1.5: Advances in Conversion of Paper
Seismograms to Digital Time Series
1112,3

Thomas Lee *, Miaki Ishii , Hiromi Ishii , & Toshihiro Morinaga*Thomasandrewlee@g.harvard.edu

Introduction

1Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA
2School Innovation Forum, 3Graduate School of Education, Kyoto University

1a. Eras of Analog and Digital Recording

Deployment of 1.4β
2a: Kyoto Tsukuba Kaisei High School
Red bars represent the seismic moment of major earthquakes

A large amount of seismic data was recorded during
the analog era (1a) and is still stored around the worldin the form of paper records (1b,c). However as aresult of their analog format, these records are often
inaccessible to modern analyses. To address thisissue, there have been several softwares developed
to convert scanned images of paper seismograms into
digital traces. DigitSeis1, a software developed by theHarvard Seismology Group, is one of the most flexible
and versatile of these, and one of the few allowing
assignment of timing.

12b: Miyazaki Prefectural Nobeoka High School

1cParticipating schools were given
materials about seismology andearthquakes. Special focus was put
upon the ways in which the analog
seismog

1b. HVO Historical Record Collection
1d: Time Assignment in DigitSeis
12:15

12:30

12:45

13:00

1e: Operation Crossroads

Converting scanned images into
digital time series via DigitSeis ispartially automated but still requires
human inputs for complications suchas crossed traces (1c) and assigningreference times (1d).

1h: Climate Change

seismograms could be used in the 2c Analysis with
Correcti
ons Neefuture to solve big problems indedscience (e.g., finding new events,
environmental monitoring, etc.).
Students were also given andenjoyed multiple opportunities tointeract with seismologists in theDigitized 1937
2eform of Q & A's, along with inEarthquake
writing and by video call.

No Activity Status After 6 Months
Installation

Analysis of New Image

Training

18%

Other

Problems Encountered
Globus (File Transfer)

None

14%
23%

10%
43%

1f: Wave-Action on Shore

1g: Hurricane Isabel

Photo: NASA

Viewing
Feedback

3aDigitSeis main window with red arrows indicating crossing traces

Changes for 1.5 include:● Cleaner UI - Less complicated menus and main-screen layout (3a)● Feedback and Note Tools - Tags can be added in areas with issues (2c,d)● Language Options - Japanese & English (others can be easily added)● More efficient memory and space usage (32-bit Windows compatible)● Parallelization - Intense calculations are sped up● Flexibility - Ability for users to control more options
For version 1.5, more focus was given to under-the-hood changes that would improve efficiency
and serve as a step in the direction of automation. One of the most work-intensive parts ofthe digitization process is the treatment of crossed traces. In previous releases of DigitSeis, thiswas a process done in a completely manual sense. One of the most exciting aspects of 1.5
is the ability to address most crossing-trace scenarios automatically.
This is achieved by first improving generation of thebinary image (where the only two things defined are"background" and "not background"), from which theobject classification is computed. With objects defined
better, trace crossings (red circles) can be detected as
areas in-between points where "background" areas
are pinched out by crossings (yellow arrows) (3b).

3bDigitized by: Manato Sano of Ritsumeikan Keisho Junior & Senior High School

2f: Exit Survey Results

Applications for digitized 1i: 1974 Mauna Ulu Eruption
analog seismograms are widespread and far-reaching. The
greatest merit of analog
records are the long time spanthey cover, allowing forquantitative analysis of long
Photo: USGS
time scale or rare phenomenon. Examples of possible analyses
quantitativeUSGS
include yields and behavior of nuclear tests (1e), behavior of past
volcanic eruptions (1i), storm strength from wave-generated
seismic noise (1f,g), and generally long time-scale problems not
typically associated with seismology such as climate change (1h).

2dOver the last two years,
improvements have been
made for better usabilitiy,efficacy,accuracy,andefficiency of the DigitSeis
software, culminating inversion 1.5 (3a). Some ofthese updates, especiallythose related to ease of use
were rolled out in the 1.4β
version used in the Japanesehigh school deployment.

Digitized by: Karen Karashima of Kyoto Tsubaka Kaisei High School

Era of Analog Recording

Photo: Nuclear Weapon Archive

Over the past six months, DigitSeis
was deployed in Japanese highschools as a research experience
where students provided the humanoversight needed for digitization.
This is the first large deployment ofDigitSeis, and in total, 142 students
from 13 high schools participated in
the program as an extracurricular
activity (2a,b). Of the 13 participating schools, 9 are interested incontinuing for another year, andthere are three schools joining forthe 2019-2020 academic year.

Advances in 1.5

45%

25%

Test Image
Digitization

Test Image
Corrections

HardwareNext Time I Want To...

Weekly Time Spent By Students> 2 HoursAlmostNothing

11%
16%

Do HarderImages

2 HoursAnalyze
New Images

Quit

17%

7%
11%

24%
45%

32%

< 30 Minutes

15%

Deployment
Students were given video-walkthroughs
and a previously digitized test analysis toDigitSeis
learn to use the DigitSeis software.
Feedback was given on this analysis(2c,d)
until
itwascompleted
satisfactorily, at which point students
were asked to progress to otherInternet
previously undigitized images (2e).

1 HourUnderstand Better

KeepAnalyzing

9%27%

Results
Most students moving beyond the test
image provided high-quality time series.
The results of an exit survey (2f)conducted at the end of March 2019show an interest in continuing from many
students, with a significant fraction
wanting to understand where things did
not work out ("Understand Better", 2f).

By applying this technique, areas of crossing are detected, and the single region of crossing canbe attributed to two separate traces along with their uncrossed portions in the classification step(i.e., overlapping is allowed). This is alsodone in an automated sense, and ishighlighted below overlapping object pixels
shown in pink (3c), and individual traces
including overlapping region shown inyellow (3d-3f). Currently, if an overlapping
region cannot be automatically separated,
it is classified as noise (orange box) (3c).

3c

3d3e

Anticipated Release Date for DigitSeis.v.1.5: Summer 2019

References: 1) Bogiatzis, P., and M. Ishii (2016). DigitSeis: A New Digitization Software for Analog Seismograms. Seismological Research Letters, 87(3), 726-736. Links: DigitSeis Main Page: http://www.seismology.harvard.edu/research/DigitSeis.html, DigitSeis Citizen Science (English): http://www.seismology.harvard.edu/research/DigitSeisJapan/index_en.html, DigitSeis Citizen Science (Japanese): http://www.seismology.harvard.edu/research/DigitSeisJapan/index.html
Acknowledgements: We thank Moeko Kobayashi of Kyoto University for assistance with translation.

3f